使用iOS手势UIGestureRecognizer

UIKit中包含了UIGestureRecognizer类，用于检测发生在设备中的手势。UIGestureRecognizer是一个抽象类，定义了所有手势的基本行为，它有下面一些子类用于处理具体的手势： 

    1、拍击UITapGestureRecognizer (任意次数的拍击)  
    2、向里或向外捏UIPinchGestureRecognizer (用于缩放)  
    3、摇动或者拖拽UIPanGestureRecognizer  
    4、擦碰UISwipeGestureRecognizer (以任意方向)  
    5、旋转UIRotationGestureRecognizer (手指朝相反方向移动)  
    6、长按UILongPressGestureRecognizer 

对于不同类型的手势识别器，具有不同的配置属性。比如UITapGestureRecognizer，可以配置拍击次数。界面接收到手势之后，可以发送一个消息，用于处理响应手势动作后的任务。当然，不同的手势识别器，发送的消息方法也会有所不同。下面列举几个具体示例代码： 

一个手指，拍击两次手势

// 创建一个手势识别器
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");
}

 

两个手指，拍击两次手势

    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");
    }

一个手指向上、向下擦碰手势

    // 向上擦碰
    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);
    }
     
    // 向下擦碰
    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);
    }

 

 旋转手势

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));
}

向里或向外捏的手势

UIPinchGestureRecognizer *twoFingerPinch =
  [[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingerPinch:)] autorelease];
[[self view] addGestureRecognizer:twoFingerPinch];
 
- (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer
{
  NSLog(@"Pinch scale: %f", recognizer.scale);
}