controller的生命週期，Autolayout解密 ，再多的內容也塞得下，只怕你滑到手酸的scroll view。

1. Standford 2015 iOS讀書會
week5
1. View Controller Lifecycle, Autolayout
2. Scroll View and Closure Capture
彼得潘

2. 課程範例download
http://web.stanford.edu/class/cs193p/cgi-bin/drupal/

3. View Controller
Lifecycle

5. 只做⼀一次
auto layout的UI直接改frame無效
此時UI元件的frame還不是auto layout算出的frame
storyboard上只要勾選use auto layout，就算沒設定constraint，
storyboard會依排版位置⾃自動補上auto layout

6. 可能被呼叫多次
在viewDidLoad & viewWillAppear做太多事會卡住UI
viewDidAppear時，UI元件的frame才是auto layout計算後排版的結果

7. 在viewWillDisappear 做太多事會卡住UI
可能被呼叫多次
viewWillDisappear可以把⼀一些UI元件拿掉，節省記憶體

8. viewDidLayoutSubviews裡UI元件的frame已是auto layout計算的結果
畫⾯面重新排版時，viewWillLayoutSubviews & viewDidLayoutSubviews會被呼叫
auto layout發⽣生在viewWillLayoutSubviews & viewDidLayoutSubviews之間

9. func setNeedsLayout()
UIView
要求下次更新畫⾯面時重新排版
func layoutIfNeeded()
如果在setNeedsLayout後⾺馬上呼叫layoutIfNeeded，⽴立即更新
func setNeedsDisplay()
重新繪製view

11. rotate

12. rotate
- (NSUInteger)supportedInterfaceOrientations;
struct UIInterfaceOrientationMask : RawOptionSetType {
init(_ rawValue: UInt)
init(rawValue: UInt)
static var Portrait: UIInterfaceOrientationMask { get }
static var LandscapeLeft: UIInterfaceOrientationMask { get }
static var LandscapeRight: UIInterfaceOrientationMask { get }
static var PortraitUpsideDown: UIInterfaceOrientationMask { get }
static var Landscape: UIInterfaceOrientationMask { get }
static var All: UIInterfaceOrientationMask { get }
static var AllButUpsideDown: UIInterfaceOrientationMask { get }
}
override func supportedInterfaceOrientations() -> Int {
return Int(UIInterfaceOrientationMask.Portrait.rawValue)
}

13. rotate
UINavigationController &
UITabBarController的rotate

14. 接收memory waring: AppDelegate & view controller

15. cell的awakeFromNib()被呼叫時，
outlet已經設定
xib載⼊入時，當awakeFromNib被呼叫，outlet也已設定
let nib = UINib(nibName: "Red", bundle: nil)
let array = nib.instantiateWithOwner(nil , options: nil )
view controller的
init(coder aDecoder: NSCoder) &
awakeFromNib()被呼叫時，
outlet都還沒設定

16. Autolayout

18. 神奇的Autolayout公式

19. 神奇的Autolayout公式
let imageView = UIImageView(frame: CGRect(x: 10, y: 10, width: 300, height: 300))
self.view.addSubview(imageView)
imageView.image = UIImage(named: "baby.png")
imageView.setTranslatesAutoresizingMaskIntoConstraints(false)
let bottomConstraint = NSLayoutConstraint(item: imageView, attribute:
NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute:
NSLayoutAttribute.Bottom, multiplier: 1, constant: -10)
self.view.addConstraint(bottomConstraint)

20. visual format language
http://www.knowstack.com/swift-autolayout-visual-format-
language-sample-code/

21. 調整item欄位

22. 調整relation欄位

23. 調整constant & multiplier

24. 設定20%的寬度

25. constrain to margins

26. margin

27. 修改constraint
拉outlet到constraint

28. layout guide
status bar, navigation bar, tab bar, 熱點，電話來電

30. 5 *4 和 4*5，但需設定4種

31. 利⽤用anyk其實只要設定2種

32. ex: 在any height compact width設定的條件也會套⽤用在
regular height compact width 和
compact height compact width

33. baseline alignment
This lines up the views according to their baseline, which for
text based views is the bottom of text that does not drop down
(like g, p, j, etc). For non-text views it is the same as the
bottom edge.

35. 利⽤用preview預覽

36. preview的size和語⾔言
leading

37. 快速search元件
search裡輸⼊入⽂文字

38. 按住shift可以⼀一次
設定多個條件

39. 讓2個button置中
⽅方法1: 左右各放⼀一個view
⽅方法2: 將兩個button放在⼀一個另⼀一個view，再將此view置中

40. 設定action的argument

41. { }() : 執⾏行closure
static let database: Dictionary<String, User> = {
var theDatabase = Dictionary<String, User>()
for user in [
User(name: "John Appleseed", company: "Apple", login: "japple", password: "foo"),
User(name: "Madison Bumgarner", company: "World Champion San Francisco Giants",
login: "madbum", password: "foo"),
User(name: "John Hennessy", company: "Stanford", login: "hennessy", password: "foo"),
User(name: "Bad Guy", company: "Criminals, Inc.", login: "baddie", password: "foo")
] {
theDatabase[user.login] = user
}
return theDatabase
}()

42. Images.xcassets
依device客製
依size客製

43. Images.xcassets

44. UI元件的expend & compress
hugging: content does not want to grow
compression: content does not want to shrink

45. ⼤大家的compression都是750

46. 解法:將image的compression
設成700

47. demo
197 * 294.5
image <UIImageView: 0x7ff041682930; frame = (16 253.5; 197 294.5); autoresize = RM+BM;
userInteractionEnabled = NO; layer = <CALayer: 0x7ff041682c70>>

48. demo
image <UIImageView: 0x7fccb9f317a0; frame = (16 142; 0 406); autoresize = RM+BM;
userInteractionEnabled = NO; layer = <CALayer: 0x7fccb9f31ae0>>

49. demo

50. 設定image view的hugging

51. 設定>=

52. 設定label的trailing space

53. 增加label的horizontal
compression

54. 設定圖⽚片⽐比例
private var image: UIImage? {
get {
return imageView?.image
}
set {
imageView?.image = newValue
if let constrainedView = imageView {
if let newImage = newValue {
aspectRatioConstraint = NSLayoutConstraint(
item: constrainedView,
attribute: .Width,
relatedBy: .Equal,
toItem: constrainedView,
attribute: .Height,
multiplier: newImage.aspectRatio,
constant: 0)
} else {
aspectRatioConstraint = nil
}
}
}
}

55. demo

56. 設定size regular height的
layout

57. 只在某個layout
出現某個UI元件或constraint

58. 移除某個layout下的所有
constraint
1 2
按X

59. scroll view

63. demo
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let image = UIImage(named: "book")
imageView = UIImageView(frame: CGRect(x: 100, y: 100, width: 1000, height: 1000))
imageView.image = image
self.myScrollView.addSubview(imageView)
self.myScrollView.contentSize = CGSize(width: 1000, height: 1000)
self.myScrollView.delegate = self
}
func scrollViewDidScroll(scrollView: UIScrollView) {
let rect = self.imageView.convertRect(self.myScrollView.bounds, fromView:
self.myScrollView)
println("rect (rect)")
}

64. var directionalLockEnabled: Bool
限制某個⽅方向，不能同時⽔水平垂直滑動
self.myScrollView.contentInset = UIEdgeInsets(top: 10, left: 100, bottom: 0, right: 0)
⼀一開始contentOffset的位置是-10, -100

65. func zoomToRect(rect: CGRect, animated: Bool)
顯⽰示放⼤大的view裡的rect區塊
(viewForZoomingInScrollView回傳的view)
放⼤大時，viewForZoomingInScrollView回傳的view的subview也會⼀一起放⼤大

66. sizeToFit()
ex: image view縮放到圖⽚片的⼤大⼩小
label縮放到⽂文字的⼤大⼩小
label縮放時，會以⺫⽬目前的寬度為最⼤大寬度，計算需要的⾼高度
let label = UILabel()
label.text = "有⼀一段⾛走過的路我不會忘，有⼀一個愛過的⼈人放在⼼心上，雖然啊⼀一路跌跌撞撞，
也是種成⻑⾧長，我不怕 不是逞強"
self.view.addSubview(label)
label.numberOfLines = 0
label.frame = CGRect(x: 0, y: 30, width: 100, height: 0)
label.sizeToFit()
self.view .addSubview(label)

67. check view是否在畫⾯面上
if view.window != nil {
fetchImage()
}
以navigation controller為例

71. weak & unowned
希望它是不變的常數還是可變的變數，若是前者則選
unowned。
weak只能作⽤用於物件
是否可以為nil，若接受nil只能選weak。