Modernizes your
Objective-C
Massimo Oliviero!
Software Developer

@maxoly
About
Massimo Oliviero

Freelance Software Developer & Trainer

#pragma mark founder
!
www.massimooliviero.net

massimo.ol...
#pragma mark
iOS & OSX Developers Community
We organize the #PragmaConference, an event
dedicated to iOS and OS X developm...
Agenda
Agenda
‣ Syntax
Agenda
‣ Syntax
‣ Conventions
Agenda
‣ Syntax
‣ Conventions
‣ Coding
Agenda
‣ Syntax
‣ Conventions
‣ Coding
‣ Framework
Syntax
use new literal syntax
you can create NSArray, NSDictionary, NSNumber with a simple @
Literals
NSArray *names = [NSArray
arrayWithObjects:@"Marco", @"Paolo", @"Flavio", nil];
NSDictionary *jobs = [NSDictionar...
Literals
NSArray *names = [NSArray
arrayWithObjects:@"Marco", @"Paolo", @"Flavio", nil];
NSDictionary *jobs = [NSDictionar...
Literals
Literals
‣ The new object literals significantly reduce the
verbosity of code
Literals
‣ The new object literals significantly reduce the
verbosity of code
‣ All objects made via literal (such an arra...
Literals
‣ The new object literals significantly reduce the
verbosity of code
‣ All objects made via literal (such an arra...
use Object Subscripting
Object pointer values can now be used with C’s subscripting operator
Object Subscripting
!
NSArray *people = @[ @"John", @"Steve", @"Bill" ];
NSString *steve = [people objectAtIndex:1];
NSDic...
Object Subscripting
!
NSArray *people = @[ @"John", @"Steve", @"Bill" ];
NSString *steve = [people objectAtIndex:1];
NSDic...
Custom Subscripting
Custom Subscripting
@interface MGACustomer : NSObject
@property (nonatomic, strong, readonly) NSArray *orders;
// Custom I...
Object Subscripting
Object Subscripting
‣ Subscripting syntax can significantly reduce the
verbosity of code that deals heavily with arrays an...
Object Subscripting
‣ Subscripting syntax can significantly reduce the
verbosity of code that deals heavily with arrays an...
Object Subscripting
‣ Subscripting syntax can significantly reduce the
verbosity of code that deals heavily with arrays an...
use new @import declaration
@import is the new compiler directive introduced by Modules
@import
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h> // you must add framework from Target > Build Phases
!
!
@interf...
@import
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h> // you must add framework from Target > Build Phases
!
!
@interf...
@import
@import
‣ Modules provide an alternative, simpler way to use
software libraries that provides better compile-time
scalabil...
@import
‣ Modules provide an alternative, simpler way to use
software libraries that provides better compile-time
scalabil...
@import
‣ Modules provide an alternative, simpler way to use
software libraries that provides better compile-time
scalabil...
use new type instancetype
instancetype is a contextual keyword that can be used as a result type to signal that a
method r...
instancetype
@interface MGACustomer : NSObject
!
@property (nonatomic, readwrite, copy) NSString *name;
+ (id)customerWith...
instancetype
@interface MGACustomer : NSObject
!
@property (nonatomic, readwrite, copy) NSString *name;
+ (id)customerWith...
instancetype
@interface MGACustomer : NSObject
!
@property (nonatomic, readwrite, copy) NSString *name;
+ (id)customerWith...
instancetype
instancetype
‣ With instancetype, the compiler will correctly infer
that the result of convenient constructor is an
instan...
instancetype
‣ With instancetype, the compiler will correctly infer
that the result of convenient constructor is an
instan...
instancetype
‣ With instancetype, the compiler will correctly infer
that the result of convenient constructor is an
instan...
use auto property synthesis
synthesize not necessary for @property since Xcode 4.4
auto property synthesis
@interface MGACustomer : NSObject
!
@property (nonatomic, readwrite, copy) NSString *name;
@proper...
auto property synthesis
@interface MGACustomer : NSObject
!
@property (nonatomic, readwrite, copy) NSString *name;
@proper...
auto property synthesis
auto property synthesis
‣ Clang provides support for autosynthesis of declared
properties. Using this feature, clang provi...
auto property synthesis
‣ Clang provides support for autosynthesis of declared
properties. Using this feature, clang provi...
auto property synthesis
‣ Clang provides support for autosynthesis of declared
properties. Using this feature, clang provi...
use copy for any immutable class
for attributes whose type is an immutable value class that conforms to the
NSCopying prot...
copy attribute
!
!
@interface MGACustomer : NSObject
!
@property (nonatomic, readwrite, strong) NSString *name;
@property ...
copy attribute
!
!
@interface MGACustomer : NSObject
!
@property (nonatomic, readwrite, strong) NSString *name;
@property ...
copy attribute
copy attribute
‣ The reason of copy is that it is possible to have a
property that is declared as an immutable type (such
...
copy attribute
‣ The reason of copy is that it is possible to have a
property that is declared as an immutable type (such
...
NS_ENUM & NS_OPTIONS macro
these macros are the new, preferred way to declare enum types.
NS_ENUM
typedef enum MGAUserProfile : NSUInteger
{
MGAUserProfileAdmin,
MGAUserProfileGuest,
MGAUserProfileOperator
} MGAU...
NS_ENUM
typedef enum MGAUserProfile : NSUInteger
{
MGAUserProfileAdmin,
MGAUserProfileGuest,
MGAUserProfileOperator
} MGAU...
NS_OPTIONS
typedef enum MGAUserProfile : NSUInteger
{
MGAUserProfileAdmin = 1 << 0,
MGAUserProfileGuest = 1 << 1,
MGAUserP...
NS_OPTIONS
typedef enum MGAUserProfile : NSUInteger
{
MGAUserProfileAdmin = 1 << 0,
MGAUserProfileGuest = 1 << 1,
MGAUserP...
NS_ENUM & NS_OPTIONS
NS_ENUM & NS_OPTIONS
‣ The new macros combines the best of all ways to
declare an enum or an option, and even provide hint...
NS_ENUM & NS_OPTIONS
‣ The new macros combines the best of all ways to
declare an enum or an option, and even provide hint...
use extern const not #define
the best way to define a globally accessible constant is extern const
extern const
// Constants.h
#define kMGAProjectConst @“myString"
#define kMGASomeMagicValue 42
extern const
// Constants.h
#define kMGAProjectConst @“myString"
#define kMGASomeMagicValue 42
extern const
// Constants.h
extern NSStr...
// Constants.h
#define kMGAProjectConst @“myString"
#define kMGASomeMagicValue 42
extern const
// Constants.h
extern NSStr...
extern const
extern const
‣ It ensures that the compiler do a static type
checking and emit a warning if you try to use it
somewhere wh...
extern const
‣ It ensures that the compiler do a static type
checking and emit a warning if you try to use it
somewhere wh...
extern const
‣ It ensures that the compiler do a static type
checking and emit a warning if you try to use it
somewhere wh...
use Foundation Data Types
if you are unsure, the Foundation Data Types (like NSInterger or CGFloat) are the best
choice be...
Foundation Data Types
Foundation Data Types
‣ The Fondation Data Types were introduced to make it
easier to write code that works on both 32-bit...
Foundation Data Types
‣ The Fondation Data Types were introduced to make it
easier to write code that works on both 32-bit...
Foundation Data Types
‣ The Fondation Data Types were introduced to make it
easier to write code that works on both 32-bit...
Use Class Extensions to Hide Private Data
Class extensions are often used to extend the public interface with additional p...
// MGAMapViewController.h
@interface MGAMapViewController : UIViewController
!
!
!
@end
!
// MGAMapViewController.m
@inter...
// MGAMapViewController.h
@interface MGAMapViewController : UIViewController
!
!
!
@end
!
// MGAMapViewController.m
@inter...
// MGAMapViewController.h
@interface MGAMapViewController : UIViewController
!
!
!
@end
!
// MGAMapViewController.m
@inter...
// MGAMapViewController.h
@interface MGAMapViewController : UIViewController
!
!
!
@end
!
// MGAMapViewController.m
@inter...
// MGAMapViewController.h
@interface MGAMapViewController : UIViewController
!
!
!
@end
!
// MGAMapViewController.m
@inter...
Class Extensions
Class Extensions
‣ A class extension bears some similarity to a category,
but it can only be added to a class for which yo...
Class Extensions
‣ A class extension bears some similarity to a category,
but it can only be added to a class for which yo...
Class Extensions
Class Extensions
‣ It’s possible to use a class extension to add custom
instance variables. These are declared inside brac...
Class Extensions
‣ It’s possible to use a class extension to add custom
instance variables. These are declared inside brac...
Class Extensions
‣ It’s possible to use a class extension to add custom
instance variables. These are declared inside brac...
Conventions
use prefixes on all classes
classes must be named uniquely in order to avoid name clashes
use prefixes on all classes
@interface Customer : NSObject
!
@property (nonatomic, readwrite, copy) NSString *name;
@prope...
use prefixes on all classes
@interface Customer : NSObject
!
@property (nonatomic, readwrite, copy) NSString *name;
@prope...
use prefixes on all classes
use prefixes on all classes
‣ Choose a prefix with at least 3 uppercase chars that are
significant for the project
use prefixes on all classes
‣ Choose a prefix with at least 3 uppercase chars that are
significant for the project
‣ Two-l...
use prefixes on all classes
‣ Choose a prefix with at least 3 uppercase chars that are
significant for the project
‣ Two-l...
use a prefix for method names in categories
in a category you should include a prefix on the method name to avoid clashes
prefix category methods
!
@interface NSString (MGAAdditions)
!
- (NSString *)reverse;
- (NSString *)sha256;
!
@end
prefix category methods
!
@interface NSString (MGAAdditions)
!
- (NSString *)reverse;
- (NSString *)sha256;
!
@end
!
@inte...
prefix category methods
prefix category methods
‣ If the name of a method declared in a category is the same as a
method in the original class, or...
prefix category methods
‣ If the name of a method declared in a category is the same as a
method in the original class, or...
properly define BOOL property
for Boolean properties the getter method should start with is
properly define BOOL property
!
@interface MGAUser
!
@property (nonatomic, assign) BOOL authenticated;
!
@end
!
@interface...
use ~iphone and ~ipad
if you’re developing a universal app add tilde to xib name instead of underscore
!
!
~iphone and ~ipad
// MGAHomeViewController_iPhone.xib
// MGAHomeViewController_iPad.xib
!
@implementation MGAHomeViewContr...
~iphone and ~ipad
// MGAHomeViewController_iPhone.xib
// MGAHomeViewController_iPad.xib
!
@implementation MGAHomeViewContr...
~iphone and ~ipad
// MGAHomeViewController_iPhone.xib
// MGAHomeViewController_iPad.xib
!
@implementation MGAHomeViewContr...
use ~iphone and ~ipad
use ~iphone and ~ipad
‣ Adding ~iphone and ~ipad to xib file name, the
runtime will automatically infer the correct xib to...
use ~iphone and ~ipad
‣ Adding ~iphone and ~ipad to xib file name, the
runtime will automatically infer the correct xib to...
organize #import statements
it’s a good practice grouping and commenting #import statements
organize #import statements
!
#import <CoreData/CoreData.h>
!
#import "MGAMapViewController.h"
#import “MGAPictureView.h"
...
organize #import statements
!
#import <CoreData/CoreData.h>
!
#import "MGAMapViewController.h"
#import “MGAPictureView.h"
...
organize #import statements
organize #import statements
‣ group #imports
organize #import statements
‣ group #imports
‣ comment the groups
organize #import statements
‣ group #imports
‣ comment the groups
‣ If your are pedantic you can sort #import by length :)
use #pragma mark
organize your code, visually
#pragma mark
#pragma mark - View
!
- (void)viewDidLoad
{
[super viewDidLoad];
…
}
!
- (void)viewWillAppear:(BOOL)animated
...
#pragma mark
#pragma mark
#pragma mark
‣ Use #pragma mark in your @implementation to divide
code into logical sections
#pragma mark
‣ Use #pragma mark in your @implementation to divide
code into logical sections
‣ It is also a way to organiz...
Coding
don’t #import in header file
most #import statements should only be written in .m files, not .h headers
don’t #import in header file
#import "MGAUser.h"
#import "MGANetworkManager.h"
!
@interface MGALoginViewController : UIVie...
don’t #import in header file
#import "MGAUser.h"
#import "MGANetworkManager.h"
!
@interface MGALoginViewController : UIVie...
don’t #import in header file
don’t #import in header file
‣ Rather than adding #import statements for each class,
it's good practice to use forward cla...
don’t #import in header file
‣ Rather than adding #import statements for each class,
it's good practice to use forward cla...
don’t #import in header file
‣ Rather than adding #import statements for each class,
it's good practice to use forward cla...
use typedef to simplify Block syntax
If you need to define more than one block with the same signature, you might like to
...
blocks with typedef
blocks with typedef
!
!
!
@interface MGACustomer
!
!
!
- (void)createOrder:(void(^)(MGAOrder *order))completion;
!
@end
blocks with typedef
!
!
!
@interface MGACustomer
!
!
!
- (void)createOrder:(void(^)(MGAOrder *order))completion;
!
@end
ty...
blocks with typedef
!
!
!
@interface MGACustomer
!
!
!
- (void)createOrder:(void(^)(MGAOrder *order))completion;
!
@end
ty...
blocks with typedef
!
!
!
@interface MGACustomer
!
!
!
- (void)createOrder:(void(^)(MGAOrder *order))completion;
!
@end
ty...
create types for blocks
create types for blocks
‣ types improve readability and clean up your method
definitions, life will be easier and It’s hig...
create types for blocks
‣ types improve readability and clean up your method
definitions, life will be easier and It’s hig...
how to access ivars
Oh my!
how to access ivars
!
- (instancetype)initWithUser:(MGAUser *)user
{
self = [super init];
if (self)
{
_user = user;
}
retu...
how to access ivars
how to access ivars
‣ Direct access bypasses the property’s memory-
management semantics defined by the setter
how to access ivars
‣ Direct access bypasses the property’s memory-
management semantics defined by the setter
‣ KVO notif...
how to access ivars
‣ Direct access bypasses the property’s memory-
management semantics defined by the setter
‣ KVO notif...
how to access ivars
‣ Direct access bypasses the property’s memory-
management semantics defined by the setter
‣ KVO notif...
always declare atomic/nonatomic
Properties are declared as atomic by default
declare atomic/nonatomic
#import <UIKit/UIKit.h>
!
@interface MGAMapViewController : UIViewController
!
@property (readonl...
declare atomic/nonatomic
#import <UIKit/UIKit.h>
!
@interface MGAMapViewController : UIViewController
!
@property (readonl...
declare atomic/nonatomic
#import <UIKit/UIKit.h>
!
@interface MGAMapViewController : UIViewController
!
@property (readonl...
declare atomic/nonatomic
declare atomic/nonatomic
‣ By default, synthesized accessors include locking to
make them atomic
declare atomic/nonatomic
‣ By default, synthesized accessors include locking to
make them atomic
‣ If you not need locking...
use read-only properties
read-only properties are great for exposing information, you should use them often
read-only properties
!
@interface MGAMapViewController : UIViewController
!
@property (nonatomic, readonly) MGAUser *user;...
read-only properties
!
@interface MGAMapViewController : UIViewController
!
@property (nonatomic, readonly) MGAUser *user;...
read-only properties
!
@interface MGAMapViewController : UIViewController
!
@property (nonatomic, readonly) MGAUser *user;...
use read-only properties
use read-only properties
‣ expose object data with read-only properties, unless
you really need to allow access to interna...
use read-only properties
‣ expose object data with read-only properties, unless
you really need to allow access to interna...
use weak to avoid retain cycles
a wrong memory management involves in memory leaks
retain cycle
retain cycle
Object BObject A
retain cycle
Object B
@property (strong)
Object A
retain cycle
Object B
@property (strong)
@property (strong)
Object A
retain cycle
Object B
@property (strong)
@property (strong)
Object A
retain cycle
Object B
@property (strong)
@property (strong)
Object A
retain cycle
Object B
@property (strong)
Object A
@property (weak)
use __weak typeof
a wrong memory management involves in memory leaks
use __weak typeof
use __weak typeof
- (void)viewDidLoad
{
[super viewDidLoad];
self.manager = [[MGANetworkManager alloc] init];
!
!
!
[self....
use __weak typeof
- (void)viewDidLoad
{
[super viewDidLoad];
self.manager = [[MGANetworkManager alloc] init];
!
!
!
[self....
use __weak typeof
- (void)viewDidLoad
{
[super viewDidLoad];
self.manager = [[MGANetworkManager alloc] init];
!
!
!
[self....
use __weak typeof
- (void)viewDidLoad
{
[super viewDidLoad];
self.manager = [[MGANetworkManager alloc] init];
!
!
!
[self....
use __weak typeof
- (void)viewDidLoad
{
[super viewDidLoad];
self.manager = [[MGANetworkManager alloc] init];
!
!
!
[self....
Manage third-part libraries with CocoaPods
it’s an application level dependency manager for the Objective-C projects
Cocoapods
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
$ sudo gem install cocoapods
$ cd MyGreatApp
$ pod init
$ edit Podfile
platform :ios, '6.1'
pod 'RestKit', '~> 0...
Cocoapods
Cocoapods
‣ CocoaPods manage dependency for you, it download
source files, imports headers and configures flags
Cocoapods
‣ CocoaPods manage dependency for you, it download
source files, imports headers and configures flags
‣ CocoaPod...
Cocoapods
‣ CocoaPods manage dependency for you, it download
source files, imports headers and configures flags
‣ CocoaPod...
Cocoapods
‣ CocoaPods manage dependency for you, it download
source files, imports headers and configures flags
‣ CocoaPod...
Framework
Key-Value Coding
dynamically set and get properties and object graph
Key-Value Coding
MGACustomer *c1 = [[MGACustomer alloc] initWithName:@“ACME Inc.”];
c1.address = [[MGAAddress alloc] initW...
Key-Value Coding
MGACustomer *c1 = [[MGACustomer alloc] initWithName:@“ACME Inc.”];
c1.address = [[MGAAddress alloc] initW...
Key-Value Coding
Key-Value Coding
‣ Key-value coding is a mechanism for accessing an
object’s properties indirectly, using strings to ident...
Key-Value Coding
‣ Key-value coding is a mechanism for accessing an
object’s properties indirectly, using strings to ident...
Key-Value Coding
‣ Key-value coding is a mechanism for accessing an
object’s properties indirectly, using strings to ident...
discover KVC Collection Operators
save a few extra lines of code
KVC Collection Operators
KVC Collection Operators
MGAPerson *p1 = [[MGAPerson alloc] initWithName:@"Max" age:34];
MGAPerson *p2 = [[MGAPerson alloc...
KVC Collection Operators
KVC Collection Operators
‣ Collection operators allow actions to be performed on
the items of a collection using key path ...
KVC Collection Operators
‣ Collection operators allow actions to be performed on
the items of a collection using key path ...
KVC Collection Operators
‣ Collection operators allow actions to be performed on
the items of a collection using key path ...
discover NSBlockOperation class
NSBlockOperation
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
__weak typeof(blockOp) weakOp = blockOp;
[bl...
NSBlockOperation
NSBlockOperation
‣ NSBlockOperation is a concrete subclass that wraps
block in operations
NSBlockOperation
‣ NSBlockOperation is a concrete subclass that wraps
block in operations
‣ You can use this object to exe...
NSBlockOperation
‣ NSBlockOperation is a concrete subclass that wraps
block in operations
‣ You can use this object to exe...
NSError
it encapsulates richer and more extensible error information
Create an NSError
Create an NSError
NSString * const kMGAErrorDomain = @“com.acmeinc.MyGreatApp”;
typedef NS_ENUM(NSInteger, MGAErrorCode)
{...
Handle NSError
Handle NSError
- (void)handleError:(NSError *)error
{
if (error)
{
NSString *errorMessage;
errorMessage = [NSString string...
Consuming NSError
Consuming NSError
- (void)doLogin
{
NSString *user = self.usernameTextField.text;
NSString *pass = self.passwordTextField....
NSError
NSError
‣ An NSError object encapsulates richer and more
extensible error information than is possible using
only an error...
NSError
‣ An NSError object encapsulates richer and more
extensible error information than is possible using
only an error...
NSError
‣ An NSError object encapsulates richer and more
extensible error information than is possible using
only an error...
use NSCache
It’s a collection-like container, or cache, that stores key-value pairs, similar to the
NSMutableDictionary cl...
NSCache
NSCache
NSCache *cache = [[NSCache alloc] init];
!
!
// Sets the maximum number of objects that the cache can hold.
!
// T...
NSCache
NSCache
‣ NSCache is basically just an NSMutableDictionary that
automatically evicts objects in order to free up space
in ...
NSCache
‣ NSCache is basically just an NSMutableDictionary that
automatically evicts objects in order to free up space
in ...
NSCache
NSCache
‣ It is guaranteed to be thread-safe.
NSCache
‣ It is guaranteed to be thread-safe.
‣ It is much slower to access.
NSCache
‣ It is guaranteed to be thread-safe.
‣ It is much slower to access.
‣ It may throw out objects from time to time....
NSCache
‣ It is guaranteed to be thread-safe.
‣ It is much slower to access.
‣ It may throw out objects from time to time....
NSCache
‣ It is guaranteed to be thread-safe.
‣ It is much slower to access.
‣ It may throw out objects from time to time....
NSCache
‣ It is guaranteed to be thread-safe.
‣ It is much slower to access.
‣ It may throw out objects from time to time....
NSValue
NSValue is a simple container for a single C or Objective-C data value
NSValue
NSValue
NSMutableArray *items = [@[] mutableCopy];
[items addObject:[NSValue valueWithCGSize:CGSizeMake(200.0f, 300.0f)]];...
NSValue
NSMutableArray *items = [@[] mutableCopy];
[items addObject:[NSValue valueWithCGSize:CGSizeMake(200.0f, 300.0f)]];...
NSValue
NSValue
‣ It can hold scalars and value types, as well as pointers
and object IDs.
NSValue
‣ It can hold scalars and value types, as well as pointers
and object IDs.
‣ NSValue uses type encoding to create ...
NSValue
‣ It can hold scalars and value types, as well as pointers
and object IDs.
‣ NSValue uses type encoding to create ...
Thanks!
Massimo Oliviero
@maxoly
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Modernizes your objective C - Oliviero

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Modernizes your objective C - Oliviero

  1. 1. Modernizes your Objective-C Massimo Oliviero! Software Developer
 @maxoly
  2. 2. About Massimo Oliviero
 Freelance Software Developer & Trainer
 #pragma mark founder ! www.massimooliviero.net
 massimo.oliviero@gmail.com
 @maxoly
  3. 3. #pragma mark iOS & OSX Developers Community We organize the #PragmaConference, an event dedicated to iOS and OS X development ! http://www.pragmamark.org http://www.facebook.com/groups/pragmamark @pragmamarkorg
  4. 4. Agenda
  5. 5. Agenda ‣ Syntax
  6. 6. Agenda ‣ Syntax ‣ Conventions
  7. 7. Agenda ‣ Syntax ‣ Conventions ‣ Coding
  8. 8. Agenda ‣ Syntax ‣ Conventions ‣ Coding ‣ Framework
  9. 9. Syntax
  10. 10. use new literal syntax you can create NSArray, NSDictionary, NSNumber with a simple @
  11. 11. Literals NSArray *names = [NSArray arrayWithObjects:@"Marco", @"Paolo", @"Flavio", nil]; NSDictionary *jobs = [NSDictionary dictionaryWithObjectsAndKeys:@"Marco", @"CTO", @"Paolo", "CEO", nil]; NSNumber *one = [NSNumber numberWithInt:1]; NSNumber *boolNum = [NSNumber numberWithBool:YES]; NSNumber *square = [NSNumber numberWithDouble:sqrt(2)];
  12. 12. Literals NSArray *names = [NSArray arrayWithObjects:@"Marco", @"Paolo", @"Flavio", nil]; NSDictionary *jobs = [NSDictionary dictionaryWithObjectsAndKeys:@"Marco", @"CTO", @"Paolo", "CEO", nil]; NSNumber *one = [NSNumber numberWithInt:1]; NSNumber *boolNum = [NSNumber numberWithBool:YES]; NSNumber *square = [NSNumber numberWithDouble:sqrt(2)]; NSArray *names = @[ @"Marco", @"Paolo", @"Giuseppe" ]; ! NSDictionary *jobs = @{ @"CTO" : @"Marco", @"CEO" : @"Paolo" }; ! NSNumber *one = @1; NSNumber *boolNum = @YES; NSNumber *square = @(sqrt(2));
  13. 13. Literals
  14. 14. Literals ‣ The new object literals significantly reduce the verbosity of code
  15. 15. Literals ‣ The new object literals significantly reduce the verbosity of code ‣ All objects made via literal (such an array or a dictionary) are immutable
  16. 16. Literals ‣ The new object literals significantly reduce the verbosity of code ‣ All objects made via literal (such an array or a dictionary) are immutable ‣ Remember that @(expr) dynamically evaluates the boxed expression and returns the appropriate object literal based on its value
  17. 17. use Object Subscripting Object pointer values can now be used with C’s subscripting operator
  18. 18. Object Subscripting ! NSArray *people = @[ @"John", @"Steve", @"Bill" ]; NSString *steve = [people objectAtIndex:1]; NSDictionary *books = @{ @"123" : @"Odyssey", @"234" : @"Illiad" }; NSString *illiad = [books objectForKey:@“234"]; ! // Mutable NSMutableArray *mPeople = [people mutableCopy]; [mPeople addObject:@"Ive"]; NSMutableDictionary *mBooks = [books mutableCopy]; [mBooks setObject:@"Othello" forKey:@"876"];
  19. 19. Object Subscripting ! NSArray *people = @[ @"John", @"Steve", @"Bill" ]; NSString *steve = [people objectAtIndex:1]; NSDictionary *books = @{ @"123" : @"Odyssey", @"234" : @"Illiad" }; NSString *illiad = [books objectForKey:@“234"]; ! // Mutable NSMutableArray *mPeople = [people mutableCopy]; [mPeople addObject:@"Ive"]; NSMutableDictionary *mBooks = [books mutableCopy]; [mBooks setObject:@"Othello" forKey:@"876"]; ! NSArray *people = @[ @"John", @"Steve", @"Bill" ]; NSString *steve = people[1]; NSDictionary *books = @{ @"123" : @"Odyssey", @"234" : @"Illiad" }; NSString *illiad = books[@"234"]; ! ! // Mutable NSMutableArray *mPeople = [people mutableCopy]; mPeople[3] = @"Ive"; NSMutableDictionary *mBooks = [books mutableCopy]; mBooks[@"876"] = @"Othello";
  20. 20. Custom Subscripting
  21. 21. Custom Subscripting @interface MGACustomer : NSObject @property (nonatomic, strong, readonly) NSArray *orders; // Custom Indexed Subscripting - (id)objectAtIndexedSubscript:(NSUInteger)idx; - (void)setObject:(id)obj atIndexedSubscript:(NSUInteger)idx; // Custom Keyed Subscripting - (id)objectForKeyedSubscript:(id <NSCopying>)key; - (void)setObject:(id)obj forKeyedSubscript:(id <NSCopying>)key; @end // how to use custom subscripting - (void)foo { MGACustomer *customer = [[MGACustomer alloc] init]; id order67 = customer[67]; id order34 = customer[@"order.34"]; }
  22. 22. Object Subscripting
  23. 23. Object Subscripting ‣ Subscripting syntax can significantly reduce the verbosity of code that deals heavily with arrays and dictionaries
  24. 24. Object Subscripting ‣ Subscripting syntax can significantly reduce the verbosity of code that deals heavily with arrays and dictionaries ‣ Syntax similar to that found in common scripting languages
  25. 25. Object Subscripting ‣ Subscripting syntax can significantly reduce the verbosity of code that deals heavily with arrays and dictionaries ‣ Syntax similar to that found in common scripting languages ‣ You can extend your own classes with subscripting support
  26. 26. use new @import declaration @import is the new compiler directive introduced by Modules
  27. 27. @import #import <UIKit/UIKit.h> #import <MapKit/MapKit.h> // you must add framework from Target > Build Phases ! ! @interface MGAMapViewController : UIViewController ! @property (weak, nonatomic) IBOutlet MKMapView *mapView; ! @end
  28. 28. @import #import <UIKit/UIKit.h> #import <MapKit/MapKit.h> // you must add framework from Target > Build Phases ! ! @interface MGAMapViewController : UIViewController ! @property (weak, nonatomic) IBOutlet MKMapView *mapView; ! @end @import UIKit; @import MapKit; // no additional steps required ! ! @interface MGAMapViewController : UIViewController ! @property (weak, nonatomic) IBOutlet MKMapView *mapView; ! @end
  29. 29. @import
  30. 30. @import ‣ Modules provide an alternative, simpler way to use software libraries that provides better compile-time scalability and eliminates many of the problems inherent to using the C preprocessor to access the API of a library
  31. 31. @import ‣ Modules provide an alternative, simpler way to use software libraries that provides better compile-time scalability and eliminates many of the problems inherent to using the C preprocessor to access the API of a library ‣ Modules link frameworks automatically (no more need to link framework from Build Phases)
  32. 32. @import ‣ Modules provide an alternative, simpler way to use software libraries that provides better compile-time scalability and eliminates many of the problems inherent to using the C preprocessor to access the API of a library ‣ Modules link frameworks automatically (no more need to link framework from Build Phases) ‣ At this time, modules are only available for Apple’s frameworks and have been implicitly disabled for C++
  33. 33. use new type instancetype instancetype is a contextual keyword that can be used as a result type to signal that a method returns a related result type, you can use it as return type of an init method or a (convenient)constructor
  34. 34. instancetype @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; + (id)customerWithName:(NSString *)name; ! @end ! @implementation MGACustomer ! + (id)customerWithName:(NSString *)name { id user = [[self alloc] init]; [user setName:name]; return user; } ! @end ! ! ! ! ! ! ! !
  35. 35. instancetype @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; + (id)customerWithName:(NSString *)name; ! @end ! @implementation MGACustomer ! + (id)customerWithName:(NSString *)name { id user = [[self alloc] init]; [user setName:name]; return user; } ! @end ! ! ! ! ! ! ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; + (id)customerWithName:(NSString *)name; ! @end ! @implementation MGACustomer ! + (id)customerWithName:(NSString *)name { id user = [[self alloc] init]; [user setName:name]; return user; } ! @end ! .. ! - (void)foo { // assign an object of type MGACustomer to a string variable // will not generate any error or warning at compile-time NSString *wrong = [MGACustomer customerWithName:@"test"]; }
  36. 36. instancetype @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; + (id)customerWithName:(NSString *)name; ! @end ! @implementation MGACustomer ! + (id)customerWithName:(NSString *)name { id user = [[self alloc] init]; [user setName:name]; return user; } ! @end ! ! ! ! ! ! ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; + (id)customerWithName:(NSString *)name; ! @end ! @implementation MGACustomer ! + (id)customerWithName:(NSString *)name { id user = [[self alloc] init]; [user setName:name]; return user; } ! @end ! .. ! - (void)foo { // assign an object of type MGACustomer to a string variable // will not generate any error or warning at compile-time NSString *wrong = [MGACustomer customerWithName:@"test"]; } @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; + (instancetype)customerWithName:(NSString *)name; ! @end ! @implementation MGACustomer ! + (instancetype)customerWithName:(NSString *)name { id user = [[self alloc] init]; [user setName:name]; return user; } ! @end ! .. ! - (void)foo { // With ‘instancetype’ the compiler could infer type, it will generate: Incompatible // pointer types initializing 'NSString *' with an expression of type 'MGACustomer *' NSString *wrong = [MGACustomer customerWithName:@"test"]; }
  37. 37. instancetype
  38. 38. instancetype ‣ With instancetype, the compiler will correctly infer that the result of convenient constructor is an instance of a MGACustomer
  39. 39. instancetype ‣ With instancetype, the compiler will correctly infer that the result of convenient constructor is an instance of a MGACustomer ‣ Instancetype, unlike id, can only be used as the result type in a method declaration
  40. 40. instancetype ‣ With instancetype, the compiler will correctly infer that the result of convenient constructor is an instance of a MGACustomer ‣ Instancetype, unlike id, can only be used as the result type in a method declaration ‣ Init method should also use instancetype instead of id, instancetype is more explicit and therefore better than id
  41. 41. use auto property synthesis synthesize not necessary for @property since Xcode 4.4
  42. 42. auto property synthesis @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; @property (nonatomic, readwrite, copy) NSString *address; ! @end ! ! ! ! @implementation MGACustomer { NSString *_name; NSString *_address; } ! @synthesize name = _name; @synthesize address = _address; ! - (void)foo { _name = @"Apple Inc."; } ! @end
  43. 43. auto property synthesis @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; @property (nonatomic, readwrite, copy) NSString *address; ! @end ! ! ! ! @implementation MGACustomer { NSString *_name; NSString *_address; } ! @synthesize name = _name; @synthesize address = _address; ! - (void)foo { _name = @"Apple Inc."; } ! @end @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; @property (nonatomic, readwrite, copy) NSString *address; ! @end ! ! ! ! @implementation MGACustomer ! ! // compiler auto-synthesizes properties for you // and generate corresponding ivar(s) // with underscore as prefix ! ! ! - (void)foo { _name = @"Apple Inc.”; // you can still access to ivar } ! @end
  44. 44. auto property synthesis
  45. 45. auto property synthesis ‣ Clang provides support for autosynthesis of declared properties. Using this feature, clang provides default synthesis of those properties not declared @dynamic and not having user provided backing getter and setter methods.
  46. 46. auto property synthesis ‣ Clang provides support for autosynthesis of declared properties. Using this feature, clang provides default synthesis of those properties not declared @dynamic and not having user provided backing getter and setter methods. ‣ Auto-synthesis is not support for properties defined in a protocol
  47. 47. auto property synthesis ‣ Clang provides support for autosynthesis of declared properties. Using this feature, clang provides default synthesis of those properties not declared @dynamic and not having user provided backing getter and setter methods. ‣ Auto-synthesis is not support for properties defined in a protocol ‣ The compiler will add the ivar for you (with underscore prefix) when it adds the required accessor methods
  48. 48. use copy for any immutable class for attributes whose type is an immutable value class that conforms to the NSCopying protocol (e.g.. NSDate, NSNumber, NSArray, NSSet), you almost always should specify copy in your @property declaration
  49. 49. copy attribute ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, strong) NSString *name; @property (nonatomic, readwrite, strong) NSString *address; @property (nonatomic, readwrite, strong) NSArray *orders; @property (nonatomic, readwrite, strong) NSDate *created; ! @end !
  50. 50. copy attribute ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, strong) NSString *name; @property (nonatomic, readwrite, strong) NSString *address; @property (nonatomic, readwrite, strong) NSArray *orders; @property (nonatomic, readwrite, strong) NSDate *created; ! @end ! ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; @property (nonatomic, readwrite, copy) NSString *address; @property (nonatomic, readwrite, copy) NSArray *orders; @property (nonatomic, readwrite, copy) NSDate *created; ! @end !
  51. 51. copy attribute
  52. 52. copy attribute ‣ The reason of copy is that it is possible to have a property that is declared as an immutable type (such as NSString) yet pass it a mutable type (such as NSMutableString). In which case it is possible to change the property from outside the class
  53. 53. copy attribute ‣ The reason of copy is that it is possible to have a property that is declared as an immutable type (such as NSString) yet pass it a mutable type (such as NSMutableString). In which case it is possible to change the property from outside the class ‣ using copy is recommended, because it behaves sensibly with class clusters, sending copy to a mutable class returns an immutable copy of the object
  54. 54. NS_ENUM & NS_OPTIONS macro these macros are the new, preferred way to declare enum types.
  55. 55. NS_ENUM typedef enum MGAUserProfile : NSUInteger { MGAUserProfileAdmin, MGAUserProfileGuest, MGAUserProfileOperator } MGAUserProfile; ! ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, assign) MGAUserProfile profile; ! @end
  56. 56. NS_ENUM typedef enum MGAUserProfile : NSUInteger { MGAUserProfileAdmin, MGAUserProfileGuest, MGAUserProfileOperator } MGAUserProfile; ! ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, assign) MGAUserProfile profile; ! @end typedef NS_ENUM(NSUInteger, MGAUserProfile) { MGAUserProfileAdmin, MGAUserProfileGuest, MGAUserProfileOperator }; ! ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, assign) MGAUserProfile profile; ! @end
  57. 57. NS_OPTIONS typedef enum MGAUserProfile : NSUInteger { MGAUserProfileAdmin = 1 << 0, MGAUserProfileGuest = 1 << 1, MGAUserProfileOperator = 1 << 2 } MGAUserProfile; ! ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, assign) MGAUserProfile profile; ! @end
  58. 58. NS_OPTIONS typedef enum MGAUserProfile : NSUInteger { MGAUserProfileAdmin = 1 << 0, MGAUserProfileGuest = 1 << 1, MGAUserProfileOperator = 1 << 2 } MGAUserProfile; ! ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, assign) MGAUserProfile profile; ! @end typedef NS_OPTIONS(NSUInteger, MGAUserProfile) { MGAUserProfileAdmin = 1 << 0, MGAUserProfileGuest = 1 << 1, MGAUserProfileOperator = 1 << 2, }; ! ! ! @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, assign) MGAUserProfile profile; ! @end
  59. 59. NS_ENUM & NS_OPTIONS
  60. 60. NS_ENUM & NS_OPTIONS ‣ The new macros combines the best of all ways to declare an enum or an option, and even provide hints to the compiler for type-checking and switch statement completeness.
  61. 61. NS_ENUM & NS_OPTIONS ‣ The new macros combines the best of all ways to declare an enum or an option, and even provide hints to the compiler for type-checking and switch statement completeness. ‣ If the compiler is operating in C++11 or Objective-C+ +11 mode, the macros behave slightly differently in order to make the code compatible with the mixed mode
  62. 62. use extern const not #define the best way to define a globally accessible constant is extern const
  63. 63. extern const
  64. 64. // Constants.h #define kMGAProjectConst @“myString" #define kMGASomeMagicValue 42 extern const
  65. 65. // Constants.h #define kMGAProjectConst @“myString" #define kMGASomeMagicValue 42 extern const // Constants.h extern NSString * const kMGAProjectConst; extern CGFloat const kMGASomeMagicValue; // Constants.m #import “Constants.h" NSString * const kMGAProjectConst = @“server.com”; CGFloat const kMGASomeMagicValue = 42.0f;
  66. 66. // Constants.h #define kMGAProjectConst @“myString" #define kMGASomeMagicValue 42 extern const // Constants.h extern NSString * const kMGAProjectConst; extern CGFloat const kMGASomeMagicValue; // Constants.m #import “Constants.h" NSString * const kMGAProjectConst = @“server.com”; CGFloat const kMGASomeMagicValue = 42.0f; // Constants.h FOUNDATION_EXPORT NSString * const kMGAProjectConst; FOUNDATION_EXPORT CGFloat const kMGASomeMagicValue; ! ! ! // Constants.m #import “Constants.h" ! NSString * const kMGAProjectConst = @“server.com”; CGFloat const kMGASomeMagicValue = 42.0f;
  67. 67. extern const
  68. 68. extern const ‣ It ensures that the compiler do a static type checking and emit a warning if you try to use it somewhere where it isn't expecting
  69. 69. extern const ‣ It ensures that the compiler do a static type checking and emit a warning if you try to use it somewhere where it isn't expecting ‣ One benefit is that changing the value of a constant does not cause a rebuild of your entire program.
  70. 70. extern const ‣ It ensures that the compiler do a static type checking and emit a warning if you try to use it somewhere where it isn't expecting ‣ One benefit is that changing the value of a constant does not cause a rebuild of your entire program. ‣ Use FOUNDATION_EXPORT macro instead of extern if your code will be used in mixed C/C++ environments or on other platforms
  71. 71. use Foundation Data Types if you are unsure, the Foundation Data Types (like NSInterger or CGFloat) are the best choice because they are architecture safe versions of the corresponding C types
  72. 72. Foundation Data Types
  73. 73. Foundation Data Types ‣ The Fondation Data Types were introduced to make it easier to write code that works on both 32-bit and 64- bit without modification
  74. 74. Foundation Data Types ‣ The Fondation Data Types were introduced to make it easier to write code that works on both 32-bit and 64- bit without modification ‣ You usually want to use Foundation Data Types when you don't know what kind of processor architecture your code might run on
  75. 75. Foundation Data Types ‣ The Fondation Data Types were introduced to make it easier to write code that works on both 32-bit and 64- bit without modification ‣ You usually want to use Foundation Data Types when you don't know what kind of processor architecture your code might run on ‣ However, if you need to take control on memory footprint you can use native types
  76. 76. Use Class Extensions to Hide Private Data Class extensions are often used to extend the public interface with additional private methods, properties or ivars for use within the implementation of the class itself
  77. 77. // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () ! ! ! ! ! ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! ! ! ! ! ! @end Class Extensions
  78. 78. // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () ! ! ! ! ! ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! ! ! ! ! ! @end // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () ! ! ! ! - (void)privateMethod; ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! - (void)privateMethod { } ! @end Class Extensions
  79. 79. // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () ! ! ! ! ! ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! ! ! ! ! ! @end // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () ! ! ! ! - (void)privateMethod; ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! - (void)privateMethod { } ! @end // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () { NSString *privateString; } ! - (void)privateMethod; ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! - (void)privateMethod { privateString = @"hello"; } ! @end Class Extensions
  80. 80. // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () ! ! ! ! ! ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! ! ! ! ! ! @end // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () ! ! ! ! - (void)privateMethod; ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! - (void)privateMethod { } ! @end // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () { NSString *privateString; } ! - (void)privateMethod; ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! - (void)privateMethod { privateString = @"hello"; } ! @end Class Extensions // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) NSArray *points; ! @end ! // MGAMapViewController.m @interface MGAMapViewController () { NSString *privateString; } ! - (void)privateMethod; ! @property (nonatomic, strong, readwrite) NSArray *points; ! @end ! @implementation MGAMapViewController ! ! ! ! - (void)privateMethod { privateString = @"hello"; } ! @end
  81. 81. // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () ! ! ! ! ! ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! ! ! ! ! ! @end // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () ! ! ! ! - (void)privateMethod; ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! - (void)privateMethod { } ! @end // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! ! ! @end ! // MGAMapViewController.m @interface MGAMapViewController () { NSString *privateString; } ! - (void)privateMethod; ! ! ! @end ! @implementation MGAMapViewController ! ! ! ! - (void)privateMethod { privateString = @"hello"; } ! @end Class Extensions // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) NSArray *points; ! @end ! // MGAMapViewController.m @interface MGAMapViewController () { NSString *privateString; } ! - (void)privateMethod; ! @property (nonatomic, strong, readwrite) NSArray *points; ! @end ! @implementation MGAMapViewController ! ! ! ! - (void)privateMethod { privateString = @"hello"; } ! @end // MGAMapViewController.h @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) NSArray *points; ! @end ! // MGAMapViewController.m @interface MGAMapViewController () { NSString *privateString; } ! - (void)privateMethod; ! @property (nonatomic, strong, readwrite) NSArray *points; ! @end ! @implementation MGAMapViewController { NSInteger counter; } ! - (void)privateMethod { privateString = @"hello"; } ! @end
  82. 82. Class Extensions
  83. 83. Class Extensions ‣ A class extension bears some similarity to a category, but it can only be added to a class for which you have the source code at compile time. The methods declared by a class extension are implemented in the @implementation block for the original class
  84. 84. Class Extensions ‣ A class extension bears some similarity to a category, but it can only be added to a class for which you have the source code at compile time. The methods declared by a class extension are implemented in the @implementation block for the original class ‣ By declaring the class extension inside the source code file for the class implementation, the information stays private to the class; the header files in theory should only expose public interface for your classes
  85. 85. Class Extensions
  86. 86. Class Extensions ‣ It’s possible to use a class extension to add custom instance variables. These are declared inside braces in the class extension interface
  87. 87. Class Extensions ‣ It’s possible to use a class extension to add custom instance variables. These are declared inside braces in the class extension interface ‣ It’s also common, for example, to define a property as readonly in the interface, but as readwrite in a class extension declared above the implementation, in order that the internal methods of the class can change the property value directly
  88. 88. Class Extensions ‣ It’s possible to use a class extension to add custom instance variables. These are declared inside braces in the class extension interface ‣ It’s also common, for example, to define a property as readonly in the interface, but as readwrite in a class extension declared above the implementation, in order that the internal methods of the class can change the property value directly ‣ It’s also possible to declare an ivar in the @implemetation block
  89. 89. Conventions
  90. 90. use prefixes on all classes classes must be named uniquely in order to avoid name clashes
  91. 91. use prefixes on all classes @interface Customer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; @property (nonatomic, readwrite, copy) NSString *address; ! @end ! ! ! ! @interface HomeViewController : UIViewController ! @property (weak, nonatomic) IBOutlet UILabel *userLabel; @property (weak, nonatomic) IBOutlet UILabel *logoLabel; @property (strong, nonatomic) Customer *user; ! @end
  92. 92. use prefixes on all classes @interface Customer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; @property (nonatomic, readwrite, copy) NSString *address; ! @end ! ! ! ! @interface HomeViewController : UIViewController ! @property (weak, nonatomic) IBOutlet UILabel *userLabel; @property (weak, nonatomic) IBOutlet UILabel *logoLabel; @property (strong, nonatomic) Customer *user; ! @end @interface MGACustomer : NSObject ! @property (nonatomic, readwrite, copy) NSString *name; @property (nonatomic, readwrite, copy) NSString *address; ! @end ! ! ! ! @interface MGAHomeViewController : UIViewController ! @property (weak, nonatomic) IBOutlet UILabel *userLabel; @property (weak, nonatomic) IBOutlet UILabel *logoLabel; @property (strong, nonatomic) MAGCustomer *user; ! @end
  93. 93. use prefixes on all classes
  94. 94. use prefixes on all classes ‣ Choose a prefix with at least 3 uppercase chars that are significant for the project
  95. 95. use prefixes on all classes ‣ Choose a prefix with at least 3 uppercase chars that are significant for the project ‣ Two-letter prefixes are reserved by Apple for use in framework classes, so you must use 3 (or more)
  96. 96. use prefixes on all classes ‣ Choose a prefix with at least 3 uppercase chars that are significant for the project ‣ Two-letter prefixes are reserved by Apple for use in framework classes, so you must use 3 (or more) ‣ Objective-C classes must be named uniquely not only within the code that you’re writing in a project, but also across any frameworks or bundles you might be including. As an example, you should avoid using generic class names like ViewController or TextParser because it’s possible a framework you include in your app may fail to follow conventions and create classes with the same names.
  97. 97. use a prefix for method names in categories in a category you should include a prefix on the method name to avoid clashes
  98. 98. prefix category methods ! @interface NSString (MGAAdditions) ! - (NSString *)reverse; - (NSString *)sha256; ! @end
  99. 99. prefix category methods ! @interface NSString (MGAAdditions) ! - (NSString *)reverse; - (NSString *)sha256; ! @end ! @interface NSString (MGAAdditions) ! - (NSString *)mga_reverse; - (NSString *)mga_sha256; ! @end
  100. 100. prefix category methods
  101. 101. prefix category methods ‣ If the name of a method declared in a category is the same as a method in the original class, or a method in another category on the same class (or even a superclass), the behavior is undefined as to which method implementation is used at runtime.
  102. 102. prefix category methods ‣ If the name of a method declared in a category is the same as a method in the original class, or a method in another category on the same class (or even a superclass), the behavior is undefined as to which method implementation is used at runtime. ‣ In order to avoid undefined behavior, it’s best practice to add a prefix to method names in categories on framework classes, just like you should add a prefix to the names of your own classes. You might choose to use the same three letters you use for your class prefixes, but lowercase to follow the usual convention for method names, then an underscore, before the rest of the method name
  103. 103. properly define BOOL property for Boolean properties the getter method should start with is
  104. 104. properly define BOOL property ! @interface MGAUser ! @property (nonatomic, assign) BOOL authenticated; ! @end ! @interface MGAUser ! @property (nonatomic, assign, getter = isAuthenticated) BOOL authenticated; ! @end
  105. 105. use ~iphone and ~ipad if you’re developing a universal app add tilde to xib name instead of underscore ! !
  106. 106. ~iphone and ~ipad // MGAHomeViewController_iPhone.xib // MGAHomeViewController_iPad.xib ! @implementation MGAHomeViewController ! - (id)init { NSString *nibName = @"MGAHomeViewController_iPhone"; if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) { nibName = @"MGAHomeViewController_iPad"; } return [super initWithNibName:nibName bundle:nil]; } ! @end
  107. 107. ~iphone and ~ipad // MGAHomeViewController_iPhone.xib // MGAHomeViewController_iPad.xib ! @implementation MGAHomeViewController ! - (id)init { NSString *nibName = @"MGAHomeViewController_iPhone"; if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) { nibName = @"MGAHomeViewController_iPad"; } return [super initWithNibName:nibName bundle:nil]; } ! @end please stop doing that!
  108. 108. ~iphone and ~ipad // MGAHomeViewController_iPhone.xib // MGAHomeViewController_iPad.xib ! @implementation MGAHomeViewController ! - (id)init { NSString *nibName = @"MGAHomeViewController_iPhone"; if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) { nibName = @"MGAHomeViewController_iPad"; } return [super initWithNibName:nibName bundle:nil]; } ! @end // MGAHomeViewController~iphone.xib // MGAHomeViewController~ipad.xib ! @implementation MGAHomeViewController ! ! ! ! ! // no custom init required ! ! ! ! ! ! ! @end
  109. 109. use ~iphone and ~ipad
  110. 110. use ~iphone and ~ipad ‣ Adding ~iphone and ~ipad to xib file name, the runtime will automatically infer the correct xib to load (e.g. MGAHomeViewController~iphone.xib and MGAHomeViewController~ipad.xib)
  111. 111. use ~iphone and ~ipad ‣ Adding ~iphone and ~ipad to xib file name, the runtime will automatically infer the correct xib to load (e.g. MGAHomeViewController~iphone.xib and MGAHomeViewController~ipad.xib) ‣ note, it’s case sensitive so iPhone and iPad, with a capital P, do not work
  112. 112. organize #import statements it’s a good practice grouping and commenting #import statements
  113. 113. organize #import statements ! #import <CoreData/CoreData.h> ! #import "MGAMapViewController.h" #import “MGAPictureView.h" #import “NSString+MGAAdditions.h” ! #import “MGAUser.h" ! #import <CoreLocation/CoreLocation.h> #import “NSDate+MGAAdditions.h” ! #import “MGAOrderCell.h" #import “MGACustomer.h" #import "UIImage+MGAAdditions.h" ! #import “MGAHomeViewController.h" #import <UIKit/UIKit.h> ! #import “MGAUserCell.h"
  114. 114. organize #import statements ! #import <CoreData/CoreData.h> ! #import "MGAMapViewController.h" #import “MGAPictureView.h" #import “NSString+MGAAdditions.h” ! #import “MGAUser.h" ! #import <CoreLocation/CoreLocation.h> #import “NSDate+MGAAdditions.h” ! #import “MGAOrderCell.h" #import “MGACustomer.h" #import "UIImage+MGAAdditions.h" ! #import “MGAHomeViewController.h" #import <UIKit/UIKit.h> ! #import “MGAUserCell.h" ! // Frameworks #import <UIKit/UIKit.h> #import <CoreData/CoreData.h> #import <CoreLocation/CoreLocation.h> ! // View Controllers #import "MGAMapViewController.h" #import “MGAHomeViewController.h” ! // Views #import “MGAPictureView.h” ! // Cells #import “MGAUserCell.h” #import “MGAOrderCell.h” ! // Models #import “MGAUser.h" #import “MGACustomer.h” ! // Categories #import “NSDate+MGAAdditions.h” #import “UIImage+MGAAdditions.h" #import “NSString+MGAAdditions.h”
  115. 115. organize #import statements
  116. 116. organize #import statements ‣ group #imports
  117. 117. organize #import statements ‣ group #imports ‣ comment the groups
  118. 118. organize #import statements ‣ group #imports ‣ comment the groups ‣ If your are pedantic you can sort #import by length :)
  119. 119. use #pragma mark organize your code, visually
  120. 120. #pragma mark #pragma mark - View ! - (void)viewDidLoad { [super viewDidLoad]; … } ! - (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; … } ! #pragma mark - UIScrollViewDelegate ! - (void)scrollViewDidScroll:(UIScrollView *)scrollView { … } ! - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { … } ! #pragma mark - Actions ! - (IBAction)loginButtonTouched:(id)sender { }
  121. 121. #pragma mark
  122. 122. #pragma mark
  123. 123. #pragma mark ‣ Use #pragma mark in your @implementation to divide code into logical sections
  124. 124. #pragma mark ‣ Use #pragma mark in your @implementation to divide code into logical sections ‣ It is also a way to organize your methods in the method list pop up view in Xcode
  125. 125. Coding
  126. 126. don’t #import in header file most #import statements should only be written in .m files, not .h headers
  127. 127. don’t #import in header file #import "MGAUser.h" #import "MGANetworkManager.h" ! @interface MGALoginViewController : UIViewController ! @property (nonatomic, readonly) MGAUser *user; @property (nonatomic, strong, readwrite) MGANetworkManager *network; ! @end ! ! ! ! // MGALoginViewController.m ! @implementation MGALoginViewController ! ! @end
  128. 128. don’t #import in header file #import "MGAUser.h" #import "MGANetworkManager.h" ! @interface MGALoginViewController : UIViewController ! @property (nonatomic, readonly) MGAUser *user; @property (nonatomic, strong, readwrite) MGANetworkManager *network; ! @end ! ! ! ! // MGALoginViewController.m ! @implementation MGALoginViewController ! ! @end @class MGAUser; // forward class declaration @class MGANetworkManager; // forward class declaration ! @interface MGALoginViewController : UIViewController ! @property (nonatomic, readonly) MGAUser *user; @property (nonatomic, strong, readwrite) MGANetworkManager *network; ! @end ! ! ! ! // MGALoginViewController.m ! #import "MGAUser.h" #import “MGANetworkManager.h" ! @implementation MGALoginViewController ! ! @end
  129. 129. don’t #import in header file
  130. 130. don’t #import in header file ‣ Rather than adding #import statements for each class, it's good practice to use forward class declarations in the header, and import them in the implementation
  131. 131. don’t #import in header file ‣ Rather than adding #import statements for each class, it's good practice to use forward class declarations in the header, and import them in the implementation ‣ It reduce compile times and cyclical references
  132. 132. don’t #import in header file ‣ Rather than adding #import statements for each class, it's good practice to use forward class declarations in the header, and import them in the implementation ‣ It reduce compile times and cyclical references ‣ The one real exception is when subclassing another custom class, you'll need to #import its header.
  133. 133. use typedef to simplify Block syntax If you need to define more than one block with the same signature, you might like to define your own type for that signature
  134. 134. blocks with typedef
  135. 135. blocks with typedef ! ! ! @interface MGACustomer ! ! ! - (void)createOrder:(void(^)(MGAOrder *order))completion; ! @end
  136. 136. blocks with typedef ! ! ! @interface MGACustomer ! ! ! - (void)createOrder:(void(^)(MGAOrder *order))completion; ! @end typedef void(^MGACustomerBlock)(MGAOrder *order); ! ! @interface MGACustomer ! ! ! - (void)createOrder:(void(^)(MGAOrder *order))completion; ! @end
  137. 137. blocks with typedef ! ! ! @interface MGACustomer ! ! ! - (void)createOrder:(void(^)(MGAOrder *order))completion; ! @end typedef void(^MGACustomerBlock)(MGAOrder *order); ! ! @interface MGACustomer ! ! ! - (void)createOrder:(void(^)(MGAOrder *order))completion; ! @end typedef void(^MGACustomerBlock)(MGAOrder *order); ! ! @interface MGACustomer ! ! ! - (void)createOrder:(MGACustomerBlock)completion; ! @end
  138. 138. blocks with typedef ! ! ! @interface MGACustomer ! ! ! - (void)createOrder:(void(^)(MGAOrder *order))completion; ! @end typedef void(^MGACustomerBlock)(MGAOrder *order); ! ! @interface MGACustomer ! ! ! - (void)createOrder:(void(^)(MGAOrder *order))completion; ! @end typedef void(^MGACustomerBlock)(MGAOrder *order); ! ! @interface MGACustomer ! ! ! - (void)createOrder:(MGACustomerBlock)completion; ! @end typedef void(^MGACustomerBlock)(MGAOrder *order); ! ! @interface MGACustomer ! @property (nonatomic, copy) MGACustomerBlock completionBlock; ! - (void)createOrder:(MGACustomerBlock)completion; ! @end
  139. 139. create types for blocks
  140. 140. create types for blocks ‣ types improve readability and clean up your method definitions, life will be easier and It’s highly recommend making use of them as much as possible
  141. 141. create types for blocks ‣ types improve readability and clean up your method definitions, life will be easier and It’s highly recommend making use of them as much as possible ‣ If you have to change the block signature, it is much easier to change the typedef. The compiler, being a nice fellow, will then tell you all the places the block signature doesn’t match
  142. 142. how to access ivars Oh my!
  143. 143. how to access ivars ! - (instancetype)initWithUser:(MGAUser *)user { self = [super init]; if (self) { _user = user; } return self; } ! - (void)viewDidLoad { [super viewDidLoad]; [self.usernameLabel setText:self.user.name]; } ! - (void)createNewUser { self.usernameLabel = [THMUser alloc] init]; }
  144. 144. how to access ivars
  145. 145. how to access ivars ‣ Direct access bypasses the property’s memory- management semantics defined by the setter
  146. 146. how to access ivars ‣ Direct access bypasses the property’s memory- management semantics defined by the setter ‣ KVO notifications would not be fired when accessing the instance variables directly
  147. 147. how to access ivars ‣ Direct access bypasses the property’s memory- management semantics defined by the setter ‣ KVO notifications would not be fired when accessing the instance variables directly ‣ In init methods you should use direct instance variable access, because subclasses could override the setter
  148. 148. how to access ivars ‣ Direct access bypasses the property’s memory- management semantics defined by the setter ‣ KVO notifications would not be fired when accessing the instance variables directly ‣ In init methods you should use direct instance variable access, because subclasses could override the setter ‣ On the other part of class read/write data through properties
  149. 149. always declare atomic/nonatomic Properties are declared as atomic by default
  150. 150. declare atomic/nonatomic #import <UIKit/UIKit.h> ! @interface MGAMapViewController : UIViewController ! @property (readonly) CERUser *user; @property (copy) NSArray *locations; @property (weak) IBOutlet UITableView *tableView; ! @end
  151. 151. declare atomic/nonatomic #import <UIKit/UIKit.h> ! @interface MGAMapViewController : UIViewController ! @property (readonly) CERUser *user; @property (copy) NSArray *locations; @property (weak) IBOutlet UITableView *tableView; ! @end #import <UIKit/UIKit.h> ! @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) CERUser *user; @property (nonatomic, copy) NSArray *locations; @property (nonatomic, weak) IBOutlet UITableView *tableView; ! @end
  152. 152. declare atomic/nonatomic #import <UIKit/UIKit.h> ! @interface MGAMapViewController : UIViewController ! @property (readonly) CERUser *user; @property (copy) NSArray *locations; @property (weak) IBOutlet UITableView *tableView; ! @end #import <UIKit/UIKit.h> ! @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) CERUser *user; @property (nonatomic, copy) NSArray *locations; @property (nonatomic, weak) IBOutlet UITableView *tableView; ! @end #import <UIKit/UIKit.h> ! @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) CERUser *user; @property (nonatomic, readwrite, copy) NSArray *locations; @property (nonatomic, readwrite, weak) IBOutlet UITableView *tableView; ! @end
  153. 153. declare atomic/nonatomic
  154. 154. declare atomic/nonatomic ‣ By default, synthesized accessors include locking to make them atomic
  155. 155. declare atomic/nonatomic ‣ By default, synthesized accessors include locking to make them atomic ‣ If you not need locking on property use nonatomic on iOS, since performance is severely impacted if atomic is used
  156. 156. use read-only properties read-only properties are great for exposing information, you should use them often
  157. 157. read-only properties ! @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) MGAUser *user; @property (nonatomic, readonly) NSArray *locations; ! @end
  158. 158. read-only properties ! @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) MGAUser *user; @property (nonatomic, readonly) NSArray *locations; ! @end ! @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) MGAUser *user; @property (nonatomic, readonly) NSArray *locations; ! @end ! ! ! ! ! ! ! ! ! ! @implementation MGAMapViewController ! - (instancetype)initWithUser:(MGaUser *)user { self = [super init]; if (self) { _user = user; } return self; } ! @end
  159. 159. read-only properties ! @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) MGAUser *user; @property (nonatomic, readonly) NSArray *locations; ! @end ! @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) MGAUser *user; @property (nonatomic, readonly) NSArray *locations; ! @end ! ! ! ! ! ! ! ! ! ! @implementation MGAMapViewController ! - (instancetype)initWithUser:(MGaUser *)user { self = [super init]; if (self) { _user = user; } return self; } ! @end ! @interface MGAMapViewController : UIViewController ! @property (nonatomic, readonly) MGAUser *user; @property (nonatomic, readonly) NSArray *locations; ! @end ! ! @interface MGAMapViewController () ! @property (nonatomic, strong, readwrite) MGAUser *user; @property (nonatomic, strong, readwrite) NSArray *locations; ! @end ! ! @implementation MGAMapViewController ! - (instancetype)initWithUser:(MGAUser *)user { self = [super init]; if (self) { _user = user; } return self; } ! @end
  160. 160. use read-only properties
  161. 161. use read-only properties ‣ expose object data with read-only properties, unless you really need to allow access to internal data through a public setter
  162. 162. use read-only properties ‣ expose object data with read-only properties, unless you really need to allow access to internal data through a public setter ‣ for read-only properties, you should defined a public getter but a private setter in class extension
  163. 163. use weak to avoid retain cycles a wrong memory management involves in memory leaks
  164. 164. retain cycle
  165. 165. retain cycle Object BObject A
  166. 166. retain cycle Object B @property (strong) Object A
  167. 167. retain cycle Object B @property (strong) @property (strong) Object A
  168. 168. retain cycle Object B @property (strong) @property (strong) Object A
  169. 169. retain cycle Object B @property (strong) @property (strong) Object A
  170. 170. retain cycle Object B @property (strong) Object A @property (weak)
  171. 171. use __weak typeof a wrong memory management involves in memory leaks
  172. 172. use __weak typeof
  173. 173. use __weak typeof - (void)viewDidLoad { [super viewDidLoad]; self.manager = [[MGANetworkManager alloc] init]; ! ! ! [self.manager getUsers:^(NSArray *users, NSError *error) { if (!error) { self.users = elements; [self.usersTableView reloadData]; } }]; }
  174. 174. use __weak typeof - (void)viewDidLoad { [super viewDidLoad]; self.manager = [[MGANetworkManager alloc] init]; ! ! ! [self.manager getUsers:^(NSArray *users, NSError *error) { if (!error) { self.users = elements; [self.usersTableView reloadData]; } }]; }
  175. 175. use __weak typeof - (void)viewDidLoad { [super viewDidLoad]; self.manager = [[MGANetworkManager alloc] init]; ! ! ! [self.manager getUsers:^(NSArray *users, NSError *error) { if (!error) { self.users = elements; [self.usersTableView reloadData]; } }]; }
  176. 176. use __weak typeof - (void)viewDidLoad { [super viewDidLoad]; self.manager = [[MGANetworkManager alloc] init]; ! ! ! [self.manager getUsers:^(NSArray *users, NSError *error) { if (!error) { self.users = elements; [self.usersTableView reloadData]; } }]; } - (void)viewDidLoad { [super viewDidLoad]; self.manager = [[MGANetworkManager alloc] init]; ! __weak THMReportsViewController weakSelf = self; ! [weakSelf.manager getUsers:^(NSArray *users, NSError *error) { if (!error) { weakSelf.users = elements; [weakSelf.usersTableView reloadData]; } }]; }
  177. 177. use __weak typeof - (void)viewDidLoad { [super viewDidLoad]; self.manager = [[MGANetworkManager alloc] init]; ! ! ! [self.manager getUsers:^(NSArray *users, NSError *error) { if (!error) { self.users = elements; [self.usersTableView reloadData]; } }]; } - (void)viewDidLoad { [super viewDidLoad]; self.manager = [[MGANetworkManager alloc] init]; ! __weak THMReportsViewController weakSelf = self; ! [weakSelf.manager getUsers:^(NSArray *users, NSError *error) { if (!error) { weakSelf.users = elements; [weakSelf.usersTableView reloadData]; } }]; } - (void)viewDidLoad { [super viewDidLoad]; self.manager = [[MGANetworkManager alloc] init]; ! __weak typeof(self) weakSelf = self; ! [weakSelf.manager getUsers:^(NSArray *users, NSError *error) { if (!error) { weakSelf.users = elements; [weakSelf.usersTableView reloadData]; } }]; }
  178. 178. Manage third-part libraries with CocoaPods it’s an application level dependency manager for the Objective-C projects
  179. 179. Cocoapods
  180. 180. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile
  181. 181. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2'
  182. 182. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install
  183. 183. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install
  184. 184. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install
  185. 185. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies
  186. 186. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies
  187. 187. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies
  188. 188. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3)
  189. 189. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5)
  190. 190. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2)
  191. 191. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0)
  192. 192. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1)
  193. 193. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1)
  194. 194. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1) Using RestKit (0.22.0)
  195. 195. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1) Using RestKit (0.22.0) Using SDWebImage (3.5.4)
  196. 196. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1) Using RestKit (0.22.0) Using SDWebImage (3.5.4) Using SDWebImage-ProgressView (0.3.1)
  197. 197. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1) Using RestKit (0.22.0) Using SDWebImage (3.5.4) Using SDWebImage-ProgressView (0.3.1) Using SOCKit (1.1)
  198. 198. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1) Using RestKit (0.22.0) Using SDWebImage (3.5.4) Using SDWebImage-ProgressView (0.3.1) Using SOCKit (1.1) Using TransitionKit (2.0.0)
  199. 199. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1) Using RestKit (0.22.0) Using SDWebImage (3.5.4) Using SDWebImage-ProgressView (0.3.1) Using SOCKit (1.1) Using TransitionKit (2.0.0) Generating Pods project
  200. 200. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1) Using RestKit (0.22.0) Using SDWebImage (3.5.4) Using SDWebImage-ProgressView (0.3.1) Using SOCKit (1.1) Using TransitionKit (2.0.0) Generating Pods project Integrating client project
  201. 201. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1) Using RestKit (0.22.0) Using SDWebImage (3.5.4) Using SDWebImage-ProgressView (0.3.1) Using SOCKit (1.1) Using TransitionKit (2.0.0) Generating Pods project Integrating client project
  202. 202. Cocoapods $ sudo gem install cocoapods $ cd MyGreatApp $ pod init $ edit Podfile platform :ios, '6.1' pod 'RestKit', '~> 0.22.0' pod 'FXKeychain', '~> 1.5' pod 'SDWebImage', '~> 3.5.2' pod 'SDWebImage-ProgressView', '~> 0.3.0' pod 'RHAddressBook', '~> 1.1.1' pod 'FormatterKit', '~> 1.4.2' $ pod install Analyzing dependencies Downloading dependencies Using AFNetworking (1.3.3) Using FXKeychain (1.5) Using FormatterKit (1.4.2) Using ISO8601DateFormatterValueTransformer (0.5.0) Using RHAddressBook (1.1.1) Using RKValueTransformers (1.0.1) Using RestKit (0.22.0) Using SDWebImage (3.5.4) Using SDWebImage-ProgressView (0.3.1) Using SOCKit (1.1) Using TransitionKit (2.0.0) Generating Pods project Integrating client project $
  203. 203. Cocoapods
  204. 204. Cocoapods ‣ CocoaPods manage dependency for you, it download source files, imports headers and configures flags
  205. 205. Cocoapods ‣ CocoaPods manage dependency for you, it download source files, imports headers and configures flags ‣ CocoaPods is strongly inspired by a combination of the Ruby projects RubyGems and Bundler
  206. 206. Cocoapods ‣ CocoaPods manage dependency for you, it download source files, imports headers and configures flags ‣ CocoaPods is strongly inspired by a combination of the Ruby projects RubyGems and Bundler ‣ CocoaPods focuses on source-based distribution of third party code and automatic integration into Xcode projects
  207. 207. Cocoapods ‣ CocoaPods manage dependency for you, it download source files, imports headers and configures flags ‣ CocoaPods is strongly inspired by a combination of the Ruby projects RubyGems and Bundler ‣ CocoaPods focuses on source-based distribution of third party code and automatic integration into Xcode projects ‣ CocoaPods runs from the command line
  208. 208. Framework
  209. 209. Key-Value Coding dynamically set and get properties and object graph
  210. 210. Key-Value Coding MGACustomer *c1 = [[MGACustomer alloc] initWithName:@“ACME Inc.”]; c1.address = [[MGAAddress alloc] initWithZip:@“33568”]; ! ! [c1 valueForKey:@"name"]; // ACME Inc. [c1 valueForKeyPath:@“address.zip"]; // 33568
  211. 211. Key-Value Coding MGACustomer *c1 = [[MGACustomer alloc] initWithName:@“ACME Inc.”]; c1.address = [[MGAAddress alloc] initWithZip:@“33568”]; ! ! [c1 valueForKey:@"name"]; // ACME Inc. [c1 valueForKeyPath:@“address.zip"]; // 33568 NSArray *names = @[ @"Steve", @"Bill", @"Ive" ]; ! // you can “get the value” of any method with no parameter [names valueForKey:@"uppercaseString"]; // @[ @“STEVE”, @“BILL”, @“IVE”] [names valueForKey:@"lowercaseString"]; // @[ @“steve”, @“bill”, @“ive”] ! ! // It’s really any method. // For example, -[NSObject self] is a method like any other. [@"Steve" valueForKey:@“self"]; // @“Steve” ! ! // KVC automatically boxes and unboxes values [names valueForKey:@"length"]; // @[ @5, @4, @3 ]
  212. 212. Key-Value Coding
  213. 213. Key-Value Coding ‣ Key-value coding is a mechanism for accessing an object’s properties indirectly, using strings to identify properties
  214. 214. Key-Value Coding ‣ Key-value coding is a mechanism for accessing an object’s properties indirectly, using strings to identify properties ‣ You can get the value of any method with no parameter
  215. 215. Key-Value Coding ‣ Key-value coding is a mechanism for accessing an object’s properties indirectly, using strings to identify properties ‣ You can get the value of any method with no parameter ‣ Key-Value Coding automatically boxes and unboxes values into their object representation.
  216. 216. discover KVC Collection Operators save a few extra lines of code
  217. 217. KVC Collection Operators
  218. 218. KVC Collection Operators MGAPerson *p1 = [[MGAPerson alloc] initWithName:@"Max" age:34]; MGAPerson *p2 = [[MGAPerson alloc] initWithName:@"Steve" age:54]; MGAPerson *p3 = [[MGAPerson alloc] initWithName:@"Bill" age:62]; NSArray *people = @[ p1, p2, p3 ]; // Simple Collection Operators [people valueForKeyPath:@"@count"]; // 3 [people valueForKeyPath:@"@sum.age"]; // 150.00 [people valueForKeyPath:@"@avg.age"]; // 50.00 [people valueForKeyPath:@"@max.age"]; // 63.00 // Objects Operators [people valueForKeyPath:@"@unionOfObjects.name"]; // "Max", "Steve", “Bill" // Simple Collection Operators with NSNumber NSArray *numbers = @[ @(1), @(2), @(3) ]; [numbers valueForKeyPath:@"@max.self"]; // 3
  219. 219. KVC Collection Operators
  220. 220. KVC Collection Operators ‣ Collection operators allow actions to be performed on the items of a collection using key path notation and an action operator
  221. 221. KVC Collection Operators ‣ Collection operators allow actions to be performed on the items of a collection using key path notation and an action operator ‣ Collection operators are specialized key paths that are passed as the parameter to the valueForKeyPath: method
  222. 222. KVC Collection Operators ‣ Collection operators allow actions to be performed on the items of a collection using key path notation and an action operator ‣ Collection operators are specialized key paths that are passed as the parameter to the valueForKeyPath: method ‣ The operator is specified by a string preceded by an at sign (@)
  223. 223. discover NSBlockOperation class
  224. 224. NSBlockOperation
  225. 225. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
  226. 226. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init];
  227. 227. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp;
  228. 228. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp;
  229. 229. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^
  230. 230. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ {
  231. 231. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++)
  232. 232. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) {
  233. 233. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled])
  234. 234. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled]) {
  235. 235. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled]) { break;
  236. 236. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled]) { break; }
  237. 237. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled]) { break; }
  238. 238. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled]) { break; } NSLog(@"%i", i);
  239. 239. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled]) { break; } NSLog(@"%i", i); }
  240. 240. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled]) { break; } NSLog(@"%i", i); } }];
  241. 241. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled]) { break; } NSLog(@"%i", i); } }];
  242. 242. NSBlockOperation NSBlockOperation *blockOp = [[NSBlockOperation alloc] init]; __weak typeof(blockOp) weakOp = blockOp; [blockOp addExecutionBlock:^ { for (NSInteger i = 0; i < 10000; i++) { if ([weakOp isCancelled]) { break; } NSLog(@"%i", i); } }]; [blockOp start];
  243. 243. NSBlockOperation
  244. 244. NSBlockOperation ‣ NSBlockOperation is a concrete subclass that wraps block in operations
  245. 245. NSBlockOperation ‣ NSBlockOperation is a concrete subclass that wraps block in operations ‣ You can use this object to execute several blocks at once without having to create separate operation objects for each
  246. 246. NSBlockOperation ‣ NSBlockOperation is a concrete subclass that wraps block in operations ‣ You can use this object to execute several blocks at once without having to create separate operation objects for each ‣ When executing more than one block, the operation itself is considered finished only when all blocks have finished executing
  247. 247. NSError it encapsulates richer and more extensible error information
  248. 248. Create an NSError
  249. 249. Create an NSError NSString * const kMGAErrorDomain = @“com.acmeinc.MyGreatApp”; typedef NS_ENUM(NSInteger, MGAErrorCode) { MGAErrorCodeUnableToLocateUser = 500, MGAErrorCodeInvalidUser = 401 }; NSDictionary *userInfo = @{ NSLocalizedDescriptionKey: NSLocalizedString(@“Location error”, nil), NSLocalizedFailureReasonErrorKey : NSLocalizedString(@"The location service is not active.", nil), NSLocalizedRecoverySuggestionErrorKey : NSLocalizedString(@"Please turn on the location service and try again", nil) }; NSError *error = [NSError errorWithDomain:kMGAErrorDomain code:MGAErrorCodeUnableToLocateUser userInfo:userInfo];
  250. 250. Handle NSError
  251. 251. Handle NSError - (void)handleError:(NSError *)error { if (error) { NSString *errorMessage; errorMessage = [NSString stringWithFormat:@"%@n%@", error.localizedFailureReason, error.localizedRecoverySuggestion]; UIAlertView *alert = [[UIAlertView alloc] initWithTitle:error.localizedDescription message:errorMessage delegate:nil cancelButtonTitle:NSLocalizedString(@"OK", nil) otherButtonTitles:nil, nil]; [alert show]; } }
  252. 252. Consuming NSError
  253. 253. Consuming NSError - (void)doLogin { NSString *user = self.usernameTextField.text; NSString *pass = self.passwordTextField.text; __weak typeof(self) weakSelf = self; [self.service loginWithUser:user pass:pass completion:^(TMGAUser *user, NSError *error) { [weakSelf handleError:error]; if (!error) { [weakSelf navigateToHome]; } }]; }
  254. 254. NSError
  255. 255. NSError ‣ An NSError object encapsulates richer and more extensible error information than is possible using only an error code or error string
  256. 256. NSError ‣ An NSError object encapsulates richer and more extensible error information than is possible using only an error code or error string ‣ The core attributes of an NSError object are an error domain, a domain-specific error code and a user info dictionary containing application specific information.
  257. 257. NSError ‣ An NSError object encapsulates richer and more extensible error information than is possible using only an error code or error string ‣ The core attributes of an NSError object are an error domain, a domain-specific error code and a user info dictionary containing application specific information. ‣ Domain-specific error codes are generally defined by constants in an enum.
  258. 258. use NSCache It’s a collection-like container, or cache, that stores key-value pairs, similar to the NSMutableDictionary class.
  259. 259. NSCache
  260. 260. NSCache NSCache *cache = [[NSCache alloc] init]; ! ! // Sets the maximum number of objects that the cache can hold. ! // This limit is not a strict limit, and if the cache goes over the limit, // an object in the cache could be evicted instantly, later, or possibly never, // all depending on the implementation details of the cache. [cache setCountLimit:50]; ! ! // Sets the maximum total cost that the cache can have before it starts evicting objects ! // If adding this object to the cache causes the cache’s total cost to rise above // totalCostLimit, the cache could automatically evict some of its objects until its // total cost falls below totalCostLimit. The order in which the cache evicts objects is // not guaranteed. This limit is not a strict limit, and if the cache goes over the // limit, an object in the cache could be evicted instantly, at a later point in time, // or possibly never, all depending on the implementation details of the cache. [cache setTotalCostLimit:5000]; ! ! // Add object to cache with cost [cache setObject:customer1 forKey:@"c1" cost:10]; ! ! // Add object to cache without cost [cache setObject:customer2 forKey:@"c2"];
  261. 261. NSCache
  262. 262. NSCache ‣ NSCache is basically just an NSMutableDictionary that automatically evicts objects in order to free up space in memory as needed
  263. 263. NSCache ‣ NSCache is basically just an NSMutableDictionary that automatically evicts objects in order to free up space in memory as needed ‣ The NSCache class incorporates various auto-removal policies, which ensure that it does not use too much of the system’s memory. The system automatically carries out these policies if memory is needed by other applications. When invoked, these policies remove some items from the cache, minimizing its memory footprint.
  264. 264. NSCache
  265. 265. NSCache ‣ It is guaranteed to be thread-safe.
  266. 266. NSCache ‣ It is guaranteed to be thread-safe. ‣ It is much slower to access.
  267. 267. NSCache ‣ It is guaranteed to be thread-safe. ‣ It is much slower to access. ‣ It may throw out objects from time to time. You can set costs and limits, but they're not guaranteed to be followed.
  268. 268. NSCache ‣ It is guaranteed to be thread-safe. ‣ It is much slower to access. ‣ It may throw out objects from time to time. You can set costs and limits, but they're not guaranteed to be followed. ‣ It is not toll-free bridged to anything in CoreFoundation.
  269. 269. NSCache ‣ It is guaranteed to be thread-safe. ‣ It is much slower to access. ‣ It may throw out objects from time to time. You can set costs and limits, but they're not guaranteed to be followed. ‣ It is not toll-free bridged to anything in CoreFoundation. ‣ You can't query the number of objects that are in the cache.
  270. 270. NSCache ‣ It is guaranteed to be thread-safe. ‣ It is much slower to access. ‣ It may throw out objects from time to time. You can set costs and limits, but they're not guaranteed to be followed. ‣ It is not toll-free bridged to anything in CoreFoundation. ‣ You can't query the number of objects that are in the cache. ‣ You can't enumerate a cache.
  271. 271. NSValue NSValue is a simple container for a single C or Objective-C data value
  272. 272. NSValue
  273. 273. NSValue NSMutableArray *items = [@[] mutableCopy]; [items addObject:[NSValue valueWithCGSize:CGSizeMake(200.0f, 300.0f)]]; NSValue *sizeValue = items[0]; CGSize size = [sizeValue CGSizeValue]; // define new struct typedef struct MGAColor { float red, blue, green; } MGAColor; MGAColor color = { 255.0, 0.0f, 34.0 }; [items addObject:[NSValue valueWithBytes:&color objCType:@encode(MGAColor)]];
  274. 274. NSValue NSMutableArray *items = [@[] mutableCopy]; [items addObject:[NSValue valueWithCGSize:CGSizeMake(200.0f, 300.0f)]]; NSValue *sizeValue = items[0]; CGSize size = [sizeValue CGSizeValue]; // define new struct typedef struct MGAColor { float red, blue, green; } MGAColor; MGAColor color = { 255.0, 0.0f, 34.0 }; [items addObject:[NSValue valueWithBytes:&color objCType:@encode(MGAColor)]]; MGAUser *user = [[MGAUser alloc] init]; // it not conforms to <NSCopying> NSMutableDictionary *items = [@{} mutableCopy]; // e.g. I want to store num of login attempts of a user // because my custom class MGAUser does not conform to <NSCopying> // I can’t use it as key value. The workaround is to box user instance // into NSValue object with valueWithNonretainedObject: [items setObject:numLogin forKey:[NSValue valueWithNonretainedObject:user]];
  275. 275. NSValue
  276. 276. NSValue ‣ It can hold scalars and value types, as well as pointers and object IDs.
  277. 277. NSValue ‣ It can hold scalars and value types, as well as pointers and object IDs. ‣ NSValue uses type encoding to create the necessary data structures to represent values internally
  278. 278. NSValue ‣ It can hold scalars and value types, as well as pointers and object IDs. ‣ NSValue uses type encoding to create the necessary data structures to represent values internally ‣ valueWithNonretainedObject: allows objects to be added to a collection, without the need for satisfying <NSCopying> protocol
  279. 279. Thanks! Massimo Oliviero @maxoly
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