iOS 10 / Swift 3.0 / XCode 8 總結

1,iOS10 新增的privacy settings

iOS10添加了新的權限控制範圍 若是你嘗試訪問這些隱私數據時獲得以下錯誤：

> This app has crashed because it attempted to access privacy-sensitive
> data without a usage description.  The app's Info.plist must contain
> an NSCameraUsageDescription key with a string value explaining to the
> user how the app uses this data

由於它企圖訪問敏感數據時沒有在應用程序的Info.plist
設置privacy key 新增的privacy setting以下：

privacy setting

2, OS_ACTIVITY_MODE

更新Xcode 8 若是控制檯出現enable_level: 0, persist_level: 0, default_ttl: 0, info_ttl: 0, debug_ttl: 0, generate_symptoms: 0enable_oversize: 可經過以下方法設置：

Edit Scheme-> Run -> Arguments, 
在Environment Variables裏邊添加
OS_ACTIVITY_MODE ＝ Disable

3,iOS10 layoutIfNeed

iOS10 在一個控件上調用layoutIfNeed是隻會單獨計算約束，它所約束的控件不會生效，想要達到以前的效果須要在父級控件上調用layoutIfNeed

4, NSDate

Swift3.0會將oc的NSDate轉爲Data類型，有些操做NSDate的第三方庫會閃退

5, Notification

Swift3.0字符串類型的通知常量被定義爲struct

static let MyGreatNotification = Notification.Name("MyGreatNotification")

// Use site (no change)
NotificationCenter.default().post(name: MyController.MyGreatNotification, object: self)'

6, Zip2Sequence(::) 被移除

在Swift3.0Zip2Sequence(_:_:)方法被替換爲zip(_:_:)

7， Range<>.reversed 被移除

在Swift3.0Range<>.reversed方法被移除，被替換爲<Collection>[<Range>].indices.reversed().

var array = ["A","B","C","D"]

for i in array.indices.reversed() {

    print("\(i)")
}

輸出:3 2 1 0

8, Range新增至四種類型

Range
CountableRange
ClosedRange
CountableClosedRange

不一樣的表達式會生成不一樣的Range

var countableRange = 0..<20 'CountableRange(0..<20)'

var countableClosedRange = 0...20 'CountableClosedRange(0...20)'

9, Swift3.0 Collection 新增 index(_:)系列方法

Index的successor(), predecessor(), advancedBy(_:), advancedBy(_:limit:), or distanceTo(_:)方法被移除，這些操做被移動到Collection

myIndex.successor()  =>  myCollection.index(after: myIndex)
myIndex.predecessor()  =>  myCollection.index(before: myIndex)
myIndex.advance(by: …) => myCollection.index(myIndex, offsetBy: …)

10, iOS10 UIStatusBar過時

若是你須要操做UIStatusBar，在iOS10須要改成

- (UIStatusBarStyle)preferredStatusBarStyle {
    return UIStatusBarStyleDefault;
}

11, iOS10 UICollectionView 性能優化

在iOS10 UICollectionView 最大的改變是增長了Pre-Fetching（預加載），
若是你翻看UICollectionView的最新API你能夠發現新增了以下屬性：

@property (nonatomic, weak, nullable) id<UICollectionViewDataSourcePrefetching> prefetchDataSource 

@property (nonatomic, getter=isPrefetchingEnabled) BOOL

在iOS10 Pre-Fetching 是默認開啓的，若是出於某些緣由你不想開啓Pre-Fetching，能夠經過以下設置禁用：

collectionView.isPrefetchingEnabled = false

UICollectionViewDataSourcePrefetching協議定義以下：

@protocol UICollectionViewDataSourcePrefetching <NSObject>
@required
// indexPaths are ordered ascending by geometric distance from the collection view
- (void)collectionView:(UICollectionView *)collectionView prefetchItemsAtIndexPaths:(NSArray<NSIndexPath *> *)indexPaths NS_AVAILABLE_IOS(10_0);

@optional
// indexPaths that previously were considered as candidates for pre-fetching, but were not actually used; may be a subset of the previous call to -collectionView:prefetchItemsAtIndexPaths:
- (void)collectionView:(UICollectionView *)collectionView cancelPrefetchingForItemsAtIndexPaths:(NSArray<NSIndexPath *> *)indexPaths  NS_AVAILABLE_IOS(10_0);

@end

12, iOS10 UITableView 性能優化

和UICollectionView同樣UITableView也增長了Pre-Fetching技術，UITableView新增了以下屬性：

@property (nonatomic, weak) id<UITableViewDataSourcePrefetching> prefetchDataSource NS_AVAILABLE_IOS(10_0);

奇怪的是UITableView並無找到isPrefetchingEnabled屬性的定義

13,iOS10 UIScrollView 新增 refreshControl 屬性

UIScrollView新增了refreshControl屬性

@property (nonatomic, strong, nullable) UIRefreshControl *refreshControl NS_AVAILABLE_IOS(10_0) __TVOS_PROHIBITED;

這意味着UICollectionView和UITableView都支持refresh功能了。

咱們也能夠脫離UITableViewController使用UIRefreshControl了。

14, Swif3.0 新增做用域訪問級別 fileprivate

目前有以下訪問級別：

• 公開(public)
• 內部(internal)
• 文件外私有(fileprivate)
• 私有(private)

15，Swift3.0 容許關鍵字做爲參數標籤

Swift3.0開始咱們將能使用除inout var let關鍵字做爲參數標籤

// Swift 3 calling with argument label:
    calculateRevenue(for sales: numberOfCopies,
                     in .dollars)

    // Swift 3 declaring with argument label:
    calculateRevenue(for sales: Int,
                     in currency: Currency)


    func touchesMatching(phase: NSTouchPhase, in view: NSView?) -> Set<NSTouch>

若是你堅持要使用inout var let關鍵字可使用 `` 包裹參數標籤

func addParameter(name: String, `inout`: Bool)