UIImageView添加点击事件

我们经常会用到UIImageView的点击事件，但是 可以用不同的方法实现，按钮背景图片可以让我们形成类似的触感，但是却很难在上面添加其他内容，而最笨的方法就是在图片上加个透明的按钮，麻烦得不行，所以我们ios中有个对于UIImageView的手势添加方法，不同于按钮的是他有很多手势，不仅限与点击

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、滑动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：

一个手指两次滑动

// 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");
}

一个手指滑动

// 向上滑动
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);
}

// 向下滑动
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);
}

两个手指捏合

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

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