iOS开发：如何使用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：

1、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");

}

2、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");

} 

3、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);

}

4、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));

}

5、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);

}

6、响应上下左右滑动手势

-(void)viewDidLoad{

UISwipeGestureRecognizer *recognizer;

recognizer = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(handleSwipeFrom:)];

[recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];
recognizer = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(handleSwipeFrom:)];

[recognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];

recognizer = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(handleSwipeFrom:)];

[recognizer setDirection:(UISwipeGestureRecognizerDirectionUp)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];

UISwipeGestureRecognizer *recognizer;

recognizer = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(handleSwipeFrom:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionDown)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];

}

-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer{

if(recognizer.direction==UISwipeGestureRecognizerDirectionDown) {

NSLog(@"swipe down");
//执行程序
}
if(recognizer.direction==UISwipeGestureRecognizerDirectionUp) {

NSLog(@"swipe up");
//执行程序
}

if(recognizer.direction==UISwipeGestureRecognizerDirectionLeft) {

NSLog(@"swipe left");
//执行程序
}

if(recognizer.direction==UISwipeGestureRecognizerDirectionRight) {

NSLog(@"swipe right");
//执行程序
}

}