The document provides information about iOS development using Objective-C and Auto Layout. It discusses the popularity of iOS and Objective-C, introduces Auto Layout constraints and visual format language for layout, and provides code examples for adding constraints in code and using visual formats. It also covers detecting and resolving ambiguous layouts, setting constraint priorities, and supporting multiple device orientations and localization using Auto Layout.

1. Good to see you
Michael

2. Over 365 million iOS Devices
80% is iOS 5

3. Most used programming language
2012
Position Language
1 C
2 Java
3 Objective-C
http://bit.ly/JnA6fh

4. Objective-C
%
9.00
6.75
4.50
2.25
0
2007 2008 2009 2010 2011 2012

5. Strange in iOS SDK 6
Support iOS 5 runtime

6. Valid Architecture
armv7s - remove

7. How about Auto Layout
Disable it
NSLayoutConstraint
not supported in iOS 5

8. Facebook API
Don’t use 3.1 3.1
Use 3.0 or Deprecated ones
Accounts only on iOS 6

9. Unwind

10. Unwind Segue
Motivation
We want this

11. Need some codes and
Exit -

12. Codes
-(IBAction) dismissNext:(UIStoryboardSegue *)segue{
[self dismissViewControllerAnimated:YES
completion:^{
NSLog(@"dismissed");
}];
}

13. Codes - where ?
-(IBAction) dismissNext:(UIStoryboardSegue *)segue;
GLViewController
GLPage2ViewController

14. Codes - in the source direction of segue
-(IBAction) dismissNext:(UIStoryboardSegue *)segue{
[self dismissViewControllerAnimated:YES
completion:^{
NSLog(@"dismissed");
}];
}
GLViewController

15. Drag & Drop
GLPage2ViewController

16. Running on iOS 5
Terminating app due to uncaught exception
'NSInvalidUnarchiveOperationException', reason: 'Could not instantiate
class named UIStoryboardUnwindSegueTemplate'

17. Demo
StoryDemo

18. More

19. Rotate View Controller

20. Small but important
-shouldAutorotateToInterfaceOrientation:

21. Small but important
-shouldAutorotateToInterfaceOrientation:
shouldAutorotate
supportedInterfaceOrientations

22. Example - 只支援水平導向
-(BOOL) shouldAutorotate{
return YES;
}
-(NSUInteger)supportedInterfaceOrientations{
return UIInterfaceOrientationMaskLandscape;
}
in UIViewController

23. UIInterfaceOrientationMask
typedef enum {
UIInterfaceOrientationMaskPortrait = (1 << UIInterfaceOrientationPortrait),
UIInterfaceOrientationMaskLandscapeLeft = (1 << UIInterfaceOrientationLandscapeLeft),
UIInterfaceOrientationMaskLandscapeRight = (1 << UIInterfaceOrientationLandscapeRight),
UIInterfaceOrientationMaskPortraitUpsideDown = (1 <<
UIInterfaceOrientationPortraitUpsideDown),
UIInterfaceOrientationMaskLandscape =
(UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight),
UIInterfaceOrientationMaskAll =
(UIInterfaceOrientationMaskPortrait | UIInterfaceOrientationMaskLandscapeLeft |
UIInterfaceOrientationMaskLandscapeRight |
UIInterfaceOrientationMaskPortraitUpsideDown),
UIInterfaceOrientationMaskAllButUpsideDown =
(UIInterfaceOrientationMaskPortrait | UIInterfaceOrientationMaskLandscapeLeft |
UIInterfaceOrientationMaskLandscapeRight),
} UIInterfaceOrientationMask;

24. Layout notice
當 View Controller 被整頁性的 View Controller (如
presentViewController:animated:completion: )蓋住時，被蓋住的 View
Controller 中的 willRotateToInterfaceOrientation:duration:,
willAnimateRotationToInterfaceOrientation:duration: 和
didRotateFromInterfaceOrientation: 不會被呼叫。
善用 viewWillLayoutSubviews

25. Landscape - only App
invoke a portrait-only view controller (such as the Game Center login screen)
Crash

26. Add protocol method in AppDelegate.m
- (NSUInteger)application:(UIApplication *)application
supportedInterfaceOrientationsForWindow:(UIWindow
*)window{
return UIInterfaceOrientationMaskAllButUpsideDown;
}

27. Demo
AutoConstraintDemo

28. Auto Layout
Constraint-based

29. Why auto layout ? 768
320
480 Phone
1024 Pad
320
568 iPhone 5 ?

30. Why auto layout - Localization
Hello こんにちは
English Japanese

31. Why auto layout - Example
Hello こんにちは
English Japanese

32. What is Constraint
200
20
60 60

33. What is Constraint - code
NSLayoutConstraint *constraint = [NSLayoutConstraint
constraintWithItem:button1
attribute:NSLayoutAttributeTrailing
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeTrailing
multiplier:1.0f
constant:-60.0f];
[self.view addConstraint:constraint];
button1.trainling = self.view.trainling*1.0-60
60

34. Enable Auto Layout
button1.translatesAutoresizingMaskIntoConstraints = NO;

35. What is Constraint - more
1
button1.leading = self.view.leading*1.0+60
2
button1.trainling = self.view.trainling*1.0-60
4 3
200 button1.bottom = self.view.bottom*1.0-20
4
button1.width = nil*1.0+200
20
3
1
60 60 2

36. What is Constraint - more and code

37. What is Constraint - more and code

38. Visual Format
4
200
V:[button1]-(20)-|
20 |-(60)-[button1(200)]-(60)-|
3
1
60 60 2

39. Visual Format - Code
-(void) virtualForm{
NSDictionary * bindingDict =
NSDictionaryOfVariableBindings(button1);
NSArray * constraints = [NSLayoutConstraint
constraintsWithVisualFormat:@"|-(60)-[button1(200)]-(60)-|" options:
0 metrics:nil views:bindingDict];
[self.view addConstraints:constraints];
constraints = [NSLayoutConstraint
constraintsWithVisualFormat:@"V:[button1]-(20)-|" options:0
metrics:nil views:bindingDict];
[self.view addConstraints:constraints];
}

40. What is Constraint - Landscape
unable to satisfy all constraints
200 200
20 20
60 60 60 60

41. Unable to simultaneously satisfy constraints.
(
"<NSAutoresizingMaskLayoutConstraint:0x74563f0 h=--& v=--& V:
[UIView:0x743d0d0(480)]>",
"<NSLayoutConstraint:0x744a310 H:[UIRoundedRectButton:
0x743c350(200)]>",
"<NSLayoutConstraint:0x744a500 H:|-(60)-[UIRoundedRectButton:
0x743c350] (Names: '|':UIView:0x743d0d0 )>",
"<NSLayoutConstraint:0x744a370 H:[UIRoundedRectButton:0x743c350]-
(60)-| (Names: '|':UIView:0x743d0d0 )>"
)
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x744a370 H:[UIRoundedRectButton:0x743c350]-(60)-|
(Names: '|':UIView:0x743d0d0 )>
Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView
listed in <UIKit/UIView.h> may also be helpful.

42. Visual Format - Not Equal
-(void) virtualForm{
NSDictionary * bindingDict =
NSDictionaryOfVariableBindings(button1);
NSArray * constraints = [NSLayoutConstraint
constraintsWithVisualFormat:@"|-(>=60)-[button1(200)]-(>=60)-|"
options:0 metrics:nil views:bindingDict];
[self.view addConstraints:constraints];
constraints = [NSLayoutConstraint
constraintsWithVisualFormat:@"V:[button1]-(20)-|" options:0
metrics:nil views:bindingDict];
[self.view addConstraints:constraints];
}

43. Result

44. AMBIGUOUS LAYOUT - Detect
@interface UIWindow (AutoLayoutDebug)
+ (UIWindow *)keyWindow;
- (NSString *)_autolayoutTrace;
@end private method for debug
@implementation GLViewController
-(void) viewDidAppear:(BOOL)animated{
[super viewDidAppear:animated];
NSLog(@"%@", [[UIWindow keyWindow] _autolayoutTrace]);
}
- (void)didRotateFromInterfaceOrientation:
(UIInterfaceOrientation)fromInterfaceOrientation
{
[super didRotateFromInterfaceOrientation:
fromInterfaceOrientation];
NSLog(@"%@", [[UIWindow keyWindow] _autolayoutTrace]);
}
@end

45. AMBIGUOUS LAYOUT - Console
*<UIWindow:0x7198500>
| *<UIView:0x719b040>
| | *<UIView:0x719ae10>
| | *<UIRoundedRectButton:0x719ab40>
| | | <UIGroupTableViewCellBackground:0x719bfb0>
| | | <UIImageView:0x719c850>
| | | <UIButtonLabel:0x719db30>
*<UIWindow:0x7198500>
| *<UIView:0x719b040>
| | *<UIView:0x719ae10>
| | *<UIRoundedRectButton:0x719ab40> - AMBIGUOUS LAYOUT
| | | <UIGroupTableViewCellBackground:0x719bfb0>
| | | <UIImageView:0x719c850>
| | | <UIButtonLabel:0x719db30>

46. Exercise AMBIGUOUS
[button1 addTarget:button1 action:@selector(exerciseAmbiguityInLayout)
forControlEvents:UIControlEventTouchUpInside];

47. Add Center X
NSLayoutConstraint *constraint = [NSLayoutConstraint
constraintWithItem:button1
attribute:NSLayoutAttributeCenterX
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeCenterX
multiplier:1.0f
constant:0.0];
[self.view addConstraint:constraint];

48. It works, But...
樣好像比較順眼
Some one with the force
200 300

49. Virtual Format - Try
|-(>=60)-[button1(200)]-(>=60)-|
|-(>=60)-[button1(300)]-(>=60)-|
60
300

50. Virtual Format - Priority
-(void) virtualForm{
NSDictionary * bindingDict =
NSDictionaryOfVariableBindings(button1);
NSArray * constraints = [NSLayoutConstraint
constraintsWithVisualFormat:@"|-(60)-[button1(300@999)]-(60)-|"
options:0 metrics:nil views:bindingDict];
[self.view addConstraints:constraints];
constraints = [NSLayoutConstraint
constraintsWithVisualFormat:@"V:[button1]-(20)-|" options:0
metrics:nil views:bindingDict];
[self.view addConstraints:constraints];
} Priority 1000 means required, and default is 1000

51. Great
Demo - AutoConstraintDemo