2. What is Swift?
Swift is a new programming language created by Apple as the
language of their future. Swift was originally announced during
the Apple Worldwide Developer Conference in June of 2014.
Apple had used Objective-C, originally created for the Mac, for
over 20 years. Swift was created to make writing code easier
and more concise. Swift is perfect for beginners and has
lowered the barriers so that anyone can make apps.
3. Swift Language
fast, modern, safe,
interactive programming
language
cleaner, easier to read
than the bizarre syntax of
Objective-C.
no semicolons required
(with one statement per
line)
4. Initial Requirements
A Macintosh computer
Register as an Apple Developer
Need an Apple ID and register at http://
developer.apple.com/programs/register
Install Xcode
5. iOS Simulator
No camera or video
access
$99/year to enroll in iOS
Developer program to
test on real iOS devices/
submit to App store
9. Optionals
func findStockCode(company: String) -> String? {
if (company == "Apple") {
return "AAPL"
} else if (company == "Google") {
return "GOOG"
}
return nil
}
var stockCode:String? = findStockCode("Facebook")
let text = "Stock Code - "
let message = text + stockCode // compile-time error
println(message)
10. Unwrapping Optionals
var stockCode:String? = findStockCode("Facebook")
let text = "Stock Code - "
if stockCode{
let message = text + stockCode! // force unwrap
println(message)
}
11. Optional Chaining
class Stock {
var code: String?
var price: Double?
func findStockCode(company: String) -> Stock? {
if (company == “Apple”) {
let aapl: Stock = Stock()
aapl.code = “AAPL”
aapl.price = 90.32
return aapl
} else if (company == “Google”) {
let goog: Stock = Stock()
goog.code = “GOOG”
goog.price = 556.36
return goog
}
return nil
}
12. Optional Chaining
if let stock = findStockCode(“Facebook”) {
if let sharePrice = stock.price{
let totalCost = sharePrice * 100
println(totalCost)
}
}
13. Auto Layout
build apps to support all
screen resolutions across
iPhone and iPad models
of hardware
Retina display:
1 point = 2 pixels
iOS handles translation
between points and
pixels
14. Auto Layout Constraints
Example: button centered horizontally and vertically
regardless of screen resolution and orientation
(landscape/portrait)
Two constraints defined:
center horizontally
center vertically
In Xcode you use the Auto layout menu or Control-drag
Shift-Option click storyboard to see previews without
running the simulator(s)
15. Auto Layout Options
Align — create alignment constraints, such as aligning
the left edges of two views
Pin — create spacing constraints, such as defining the
width of a UI control
Issues — resolve layout issues; Xcode senses when
placement or layout dynamics violate a constraint
Resizing — specify how resizing affects constraints
20. dequeueReusableCellWithIdentifier method
retrieves a reusable table cell from the queue with the
cell identifier defined in the Storyboard. That way,
memory is not allocated for each row of data, but is
reused.
22. Constraining a Table View
Go to the storyboard and select the table view. In the Auto
Layout menu, click the Pin button to open the Pin Tool
menu. Select each of the dashed red line symbols. Once
selected, the dashed red line turns to a solid red line. Click
the “Add 4 Constraints” button to define 4 spacing
constraints for each side of the UITableView. In particular,
we want to ensure that the bottom of the UITableView
doesn’t go beyond the Bottom Layout Guide. If you
expand the constraints items in Document Outline, you’ll
find two horizontal space constraints and two vertical
constraints. The two horizontal space constraints ensures
that the left & right side of table view will stretch to the
edge of the view controllers. The vertical constraints are
used to resolve the 3.5-inch screen issues.
23.
24. Delegation
The delegate pattern is very common in iOS programming.
Each delegate is responsible for a specific role or task to
keep the system simple and clean. Whenever an object
needs to perform a certain task, it depends on another
object to handle it. This is known as “separation of
concerns” in software design.
The UITableView class applies this design concept. The two
protocols are designed for different purposes. The
UITableViewDataSource defines methods that are used for
managing table data. It relies on the delegate to provide the
table data. On the other hand, the UITableViewDelegate
protocol deals with the section headings and footers of the
UITableView, plus, handles the table row selection and cell
reordering.
25. Which methods to implement in UITableViewDelegate?
Online iOS Developer Reference
https://developer.apple.com/library/ios/navigation/
Access documentation right from Xcode with control-
command-? while cursor on a class or protocol
Handling Table Row Selection
27. MVC and SoC
“At the heart of MVC, and the idea that was the most
influential to later frameworks, is what I call Separated
Presentation. The idea behind Separated Presentation is to
make a clear division between domain objects that model
our perception of the real world, and presentation objects
that are the GUI elements we see on the screen. Domain
objects should be completely self contained and work
without reference to the presentation, they should also be
able to support multiple presentations, possibly
simultaneously. This approach was also an important part of
the Unix culture, and continues today allowing many
applications to be manipulated through both a graphical and
command-line interface.” —Martin Fowler
http://www.martinfowler.com/eaaDev/uiArchs.html#ModelViewController
28. Model – responsible for holding the data or any operations
on the data. The model can be as simple as an array object
that stores all the table data. Add, update and delete are
examples of the operations. These operations are usually
known as business rules.
View – manages the visual display of information. For
example, UITableView shows information in a list format. Or
the UIButton that appears on screen is another example.
Controller – the bridge between model and view. It
translates the user interaction from the view (e.g. tap) into
appropriate action to be performed in the model. For
example, the user taps a delete button in the view.
Consequently, the controller triggers a delete operation in the
model. Once finished, the controller requests the view to
refresh itself so as to reflect the update of the data model.
29. Scene and Segue
Navigation Controller — a UI component like Table View
which provides a drill-down hierarchical interface
Embed a view controller within the Navigation Controller and
create the segue (transition) between scenes in Interface
Builder in the Storyboard
scene within Storyboard is a single view controller and its
view
each scene has a dock with action and outlet
connections between the view controller and the view
Segue sits between scenes and manages the transition
between scenes — like “push” and “modal”
34. Setting Status Bar Style
Global app change: Disable “View controller-based status bar
appearance” and set status bar style in AppDelegate method
didFinishLaunchingWithOptions
UIApplication.sharedApplication().statusBarStyle = .LightContent
View controller specific by overriding preferredStatusBarStyle
method:
override func preferredStatusBarStyle() ->
UIStatusBarStyle {
return .LightContent
}
