UITapGestureRecognizer 的用法

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UITapGestureRecognizer 的用法

本文轉載自查看原文 2013-12-11 18:10 7994 iOS UI

最近在項目中用到了手勢操作，鍵盤回收時還是挺常用的，現在總結下，多謝網絡上大神們的分享。

先分享下我在項目中用的代碼：

 1 UITapGestureRecognizer * mytap=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tap_gestureRecognizer:)];
 2     [self addGestureRecognizer:mytap];
 3     [mytap release];
 4 
 5 
 6 //收回鍵盤
 7 -(void)tap_gestureRecognizer:(UITapGestureRecognizer *)tap_gest
 8 {
 9     [self.scv_stockPriceTextField resignFirstResponder];
10     [self.scv_stockAmoutTextField resignFirstResponder];
11 
12 }


//單指單擊

2: UITapGestureRecognizer *singleFingerOne = [[UITapGestureRecognizer alloc] initWithTarget:self

3: action:@selector(handleSingleFingerEvent:)];

4: singleFingerOne.numberOfTouchesRequired = 1; //手指數

5: singleFingerOne.numberOfTapsRequired = 1; //tap次數

6: singleFingerOne.delegate = self;

7:

8: //單指雙擊

9: UITapGestureRecognizer *singleFingerTwo = [[UITapGestureRecognizer alloc] initWithTarget:self

10: action:@selector(handleSingleFingerEvent:)];

11: singleFingerTwo.numberOfTouchesRequired = 1;

12: singleFingerTwo.numberOfTapsRequired = 2;

13: singleFingerTwo.delegate = self;

14:

15: //雙指單擊

16: UITapGestureRecognizer *doubleFingerOne = [[UITapGestureRecognizer alloc] initWithTarget:self

17: action:@selector(handleDoubleFingerEvent:)];

18: doubleFingerOne.numberOfTouchesRequired = 2;

19: doubleFingerOne.numberOfTapsRequired = 1;

20: doubleFingerOne.delegate = self;

21:

22: UITapGestureRecognizer *doubleFingerTwo = [[UITapGestureRecognizer alloc] initWithTarget:self

23:    action:@selector(handleDoubleFingerEvent:)];

24: doubleFingerTwo.numberOfTouchesRequired = 2;

25: doubleFingerTwo.numberOfTapsRequired = 2;

26: doubleFingerTwo.delegate = self;

27:

28: //如果不加下面的話，當單指雙擊時，會先調用單指單擊中的處理，再調用單指雙擊中的處理

29: [singleFingerOne requireGestureRecognizerToFail:singleFingerTwo];

30: //同理雙指亦是如此

31: [doubleFingerOne requireGestureRecognizerToFail:doubleFingerTwo];

32:

33: [self.view addGestureRecognizer:singleFingerOne];

34: [self.view addGestureRecognizer:singleFingerTwo];

35: [self.view addGestureRecognizer:doubleFingerOne];

36: [self.view addGestureRecognizer:doubleFingerTwo];

37:

38: [singleFingerOne release];

39: [singleFingerTwo release];

40: [doubleFingerOne release];

41: [doubleFingerTwo release];

處理事件的方法，代碼：

1: //處理單指事件

2: - (void)handleSingleFingerEvent:(UITapGestureRecognizer *)sender

3: {

4: if (sender.numberOfTapsRequired == 1) {

5: //單指單擊

6: NSLog(@"單指單擊");

7: }else if(sender.numberOfTapsRequired == 2){

8: //單指雙擊

9: NSLog(@"單指雙擊");

10: }

11: }

12: //處理雙指事件

13: - (void)handleDoubleFingerEvent:(UITapGestureRecognizer *)sender

14: {

15: if (sender.numberOfTapsRequired == 1) {

16: //雙指單擊

17: NSLog(@"雙指單擊");

18: }else if(sender.numberOfTapsRequired == 2){

19: //雙指雙擊

20: NSLog(@"雙指雙擊");

21: }

22: }

將相應代碼復制到你的工程中即可使用，由於代碼中已經有詳細的解釋說明，這里就不在重復解釋了。

代碼中只是列舉了單指與雙指對於單擊或多擊的處理，同理多指的操作需修改numberOfTouchesRequired屬性，對點擊的次數需修改numberOfTapsRequired屬性。

對於其他手勢例如UISwipeGestureRecognizer，UILongPressGestureRecognizer,UILongPressGestureRecognizer的操作使用類似處理。

UIKit中包含了UIGestureRecognizer類，用於檢測發生在設備中的手勢。UIGestureRecognizer是一個抽象類，定義了所有手勢的基本行為，它有下面一些子類用於處理具體的手勢：

    1、拍擊UITapGestureRecognizer (任意次數的拍擊)
    2、向里或向外捏UIPinchGestureRecognizer (用於縮放)
    3、搖動或者拖拽UIPanGestureRecognizer
    4、擦碰UISwipeGestureRecognizer (以任意方向)
    5、旋轉UIRotationGestureRecognizer (手指朝相反方向移動)
    6、長按UILongPressGestureRecognizer

對於不同類型的手勢識別器，具有不同的配置屬性。比如UITapGestureRecognizer，可以配置拍擊次數。界面接收到手勢之后，可以發送一個消息，用於處理響應手勢動作后的任務。當然，不同的手勢識別器，發送的消息方法也會有所不同。下面列舉幾個具體示例代碼：
http://www.ctolive.com/space-1023-do-blog-id-2107.html

標簽： Objective-C iOS

代碼片段(5)

[代碼] 一個手指，拍擊兩次手勢

 
                01 
                // 創建一個手勢識別器 
              
                02 
                UITapGestureRecognizer *oneFingerTwoTaps = 
              
                03 
                  [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerTwoTaps)] autorelease]; 
              
                04 
                   
                05 
                // Set required taps and number of touches 
              
                06 
                [oneFingerTwoTaps setNumberOfTapsRequired:2]; 
              
                07 
                [oneFingerTwoTaps setNumberOfTouchesRequired:1]; 
              
                08 
                   
                09 
                // Add the gesture to the view 
              
                10 
                [[self view] addGestureRecognizer:oneFingerTwoTaps]; 
              
                11 
                
                12 
                消息方法oneFingerTwoTaps 
              
                13 
                - (void)oneFingerTwoTaps 
              
                14 
                { 
              
                15 
                  NSLog(@"Action: One finger, two taps"); 
              
                16 
                }

[代碼] 兩個手指，拍擊兩次手勢

 
                01 
                UITapGestureRecognizer *twoFingersTwoTaps = 
              
                02 
                  [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersTwoTaps)] autorelease]; 
              
                03 
                [twoFingersTwoTaps setNumberOfTapsRequired:2]; 
              
                04 
                [twoFingersTwoTaps setNumberOfTouchesRequired:2]; 
              
                05 
                [[self view] addGestureRecognizer:twoFingersTwoTaps]; 
              
                06 
                
                07 
                消息方法twoFingersTwoTaps 
              
                08 
                - (void)twoFingersTwoTaps { 
              
                09 
                  NSLog(@"Action: Two fingers, two taps"); 
              
                10 
                }

[代碼] 一個手指向上、向下擦碰手勢

 
                01 
                // 向上擦碰 
              
                02 
                UISwipeGestureRecognizer *oneFingerSwipeUp = 
              
                03 
                  [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeUp:)] autorelease]; 
              
                04 
                [oneFingerSwipeUp setDirection:UISwipeGestureRecognizerDirectionUp]; 
              
                05 
                [[self view] addGestureRecognizer:oneFingerSwipeUp]; 
              
                06 
                
                07 
                - (void)oneFingerSwipeUp:(UISwipeGestureRecognizer *)recognizer 
              
                08 
                { 
              
                09 
                  CGPoint point = [recognizer locationInView:[self view]]; 
              
                10 
                  NSLog(@"Swipe up - start location: %f,%f", point.x, point.y); 
              
                11 
                } 
              
                12 
                
                13 
                // 向下擦碰 
              
                14 
                UISwipeGestureRecognizer *oneFingerSwipeDown = 
              
                15 
                  [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeDown:)] autorelease]; 
              
                16 
                [oneFingerSwipeDown setDirection:UISwipeGestureRecognizerDirectionDown]; 
              
                17 
                [[self view] addGestureRecognizer:oneFingerSwipeDown]; 
              
                18 
                
                19 
                - (void)oneFingerSwipeDown:(UISwipeGestureRecognizer *)recognizer 
              
                20 
                { 
              
                21 
                  CGPoint point = [recognizer locationInView:[self view]]; 
              
                22 
                  NSLog(@"Swipe down - start location: %f,%f", point.x, point.y); 
              
                23 
                }

[代碼] 旋轉手勢

 
                1 
                UIRotationGestureRecognizer *twoFingersRotate = 
              
                2 
                  [[[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersRotate:)] autorelease]; 
              
                3 
                [[self view] addGestureRecognizer:twoFingersRotate]; 
              
                4 
                
                5 
                - (void)twoFingersRotate:(UIRotationGestureRecognizer *)recognizer 
              
                6 
                { 
              
                7 
                  // Convert the radian value to show the degree of rotation 
              
                8 
                  NSLog(@"Rotation in degrees since last change: %f", [recognizer rotation] * (180 / M_PI)); 
              
                9 
                }

[代碼] 向里或向外捏的手勢

view source
              
print?

 
             1 
             UIPinchGestureRecognizer *twoFingerPinch =

 
             2 
               [[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingerPinch:)] autorelease];

 
             3 
             [[self view] addGestureRecognizer:twoFingerPinch];

4

 
             5 
             - (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer

 
             6 
             {

 
             7 
               NSLog(@"Pinch scale: %f", recognizer.scale);
}

在 iPhone 或 iPad 的開發中，除了用 touchesBegan / touchesMoved / touchesEnded 這組方法來控制使用者的手指觸控外，也可以用 UIGestureRecognizer 的衍生類別來進行判斷。用 UIGestureRecognizer 的好處在於有現成的手勢，開發者不用自己計算手指移動軌跡。UIGestureRecognizer的衍生類別有以下幾種：

UITapGestureRecognizer
UIPinchGestureRecognizer
UIRotationGestureRecognizer
UISwipeGestureRecognizer
UIPanGestureRecognizer
UILongPressGestureRecognizer

從命名上不難了解這些類別所對應代表的手勢，分別是 Tap（點一下）、Pinch（二指往內或往外撥動）、Rotation（旋轉）、Swipe（滑動，快速移動）、Pan （拖移，慢速移動）以及 LongPress（長按）。這些手勢別在使用上也很簡單，只要在使用前定義並添加到對應的視圖上即可。

// 定義一個 recognizer, 並加到需要偵測該手勢的 UIView 元件上
- (void)viewDidLoad {
    UISwipeGestureRecognizer* recognizer;
    // handleSwipeFrom 是偵測到手勢，所要呼叫的方法
    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleSwipeFrom)];
    // 不同的 Recognizer 有不同的實體變數
 // 例如 SwipeGesture 可以指定方向
 // 而 TapGesture 則可以指定次數
    recognizer.direction = UISwipeGestureRecognizerDirectionUp
    [self.view addGestureRecognizer:recognizer];
    [recognizer release];
 }
 
 - (void)handleSwipeFrom:(UISwipeGestureRecognizer*)recognizer {
    // 觸發手勢事件后，在這里作些事情
 
 // 底下是刪除手勢的方法
    [self.view removeGestureRecognizer:recognizer];
 }

問題來了。有些手勢其實是互相關聯的，例如 Tap 與 LongPress、Swipe與 Pan，或是 Tap 一次與Tap 兩次。當一個 UIView 同時添加兩個相關聯的手勢時，到底我這一下手指頭按的要算是 Tap 還是 LongPress？如果照預設作法來看，只要「先滿足條件」的就會跳出並呼叫對應方法，舉例來說，如果同時注冊了 Pan 和 Swipe，只要手指頭一移動就會觸發 Pan 然后跳出，因而永遠都不會發生 Swipe；單點與雙點的情形也是一樣，永遠都只會觸發單點，不會有雙點。

那么這個問題有解嗎？答案是肯定的，UIGestureRecognizer 有個方法叫做requireGestureRecognizerToFail，他可以指定某一個 recognizer，即便自己已經滿足條件了，也不會立刻觸發，會等到該指定的 recognizer 確定失敗之后才觸發。以同時支持單點與雙點的手勢為例，代碼如下：

- (void)viewDidLoad {
    // 單擊的 Recognizer
    UITapGestureRecognizer* singleRecognizer;
    singleRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleSingleTapFrom)];
    singleTapRecognizer.numberOfTapsRequired = 1; // 單擊
    [self.view addGestureRecognizer:singleRecognizer];
    
    // 雙擊的 Recognizer
    UITapGestureRecognizer* double;
    doubleRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleDoubleTapFrom)];
    doubleTapRecognizer.numberOfTapsRequired = 2; // 雙擊
    [self.view addGestureRecognizer:doubleRecognizer];
    
    // 關鍵在這一行，如果雙擊確定偵測失敗才會觸發單擊
    [singleRecognizer requireGestureRecognizerToFail:doubleRecognizer];
    [singleRecognizer release];
    [doubleRecognizer release];
}

來源：http://blog.csdn.net/xiaoxuan415315/article/details/7788239

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