如何使用iOS手勢UIGestureRecognizer

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、滑動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：

 

一個手指，拍擊兩次手勢

// 創建一個手勢識別器
UITapGestureRecognizer *oneFingerTwoTaps =
  [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerTwoTaps)] autorelease];
 
// Set required taps and number of touches
[oneFingerTwoTaps setNumberOfTapsRequired:2];
[oneFingerTwoTaps setNumberOfTouchesRequired:1];
 
// Add the gesture to the view
[[self view] addGestureRecognizer:oneFingerTwoTaps];

消息方法oneFingerTwoTaps
- (void)oneFingerTwoTaps
{
  NSLog(@"Action: One finger, two taps");
}

 

兩個手指，拍擊兩次手勢

UITapGestureRecognizer *twoFingersTwoTaps =
  [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersTwoTaps)] autorelease];
[twoFingersTwoTaps setNumberOfTapsRequired:2];
[twoFingersTwoTaps setNumberOfTouchesRequired:2];
[[self view] addGestureRecognizer:twoFingersTwoTaps];

消息方法twoFingersTwoTaps
- (void)twoFingersTwoTaps {
  NSLog(@"Action: Two fingers, two taps");
} 

 

一個手指向上、向下滑動手勢

// 向上滑動
UISwipeGestureRecognizer *oneFingerSwipeUp =
  [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeUp:)] autorelease];
[oneFingerSwipeUp setDirection:UISwipeGestureRecognizerDirectionUp];
[[self view] addGestureRecognizer:oneFingerSwipeUp];

- (void)oneFingerSwipeUp:(UISwipeGestureRecognizer *)recognizer
{
  CGPoint point = [recognizer locationInView:[self view]];
  NSLog(@"Swipe up - start location: %f,%f", point.x, point.y);
}

// 向下滑動
UISwipeGestureRecognizer *oneFingerSwipeDown =
  [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeDown:)] autorelease];
[oneFingerSwipeDown setDirection:UISwipeGestureRecognizerDirectionDown];
[[self view] addGestureRecognizer:oneFingerSwipeDown];

- (void)oneFingerSwipeDown:(UISwipeGestureRecognizer *)recognizer
{
  CGPoint point = [recognizer locationInView:[self view]];
  NSLog(@"Swipe down - start location: %f,%f", point.x, point.y);
}

 

旋轉手勢

UIRotationGestureRecognizer *twoFingersRotate =
  [[[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersRotate:)] autorelease];
[[self view] addGestureRecognizer:twoFingersRotate];

- (void)twoFingersRotate:(UIRotationGestureRecognizer *)recognizer
{
  // Convert the radian value to show the degree of rotation
  NSLog(@"Rotation in degrees since last change: %f", [recognizer rotation] * (180 / M_PI));
}

 

向里或向外捏的手勢

UIPinchGestureRecognizer *twoFingerPinch =
  [[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingerPinch:)] autorelease];
[[self view] addGestureRecognizer:twoFingerPinch];

- (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer
{
  NSLog(@"Pinch scale: %f", recognizer.scale);
}

 

 

 

 

 

UITapGestureRecognizer *twoFingersTwoTaps =
  [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersTwoTaps)] autorelease];
[twoFingersTwoTaps setNumberOfTapsRequired:2];
[twoFingersTwoTaps setNumberOfTouchesRequired:2];
[[self view] addGestureRecognizer:twoFingersTwoTaps];

消息方法twoFingersTwoTaps
- (void)twoFingersTwoTaps {
  NSLog(@"Action: Two fingers, two taps");
}