手势

1、UIGestureRecognizer介绍 手势识别在iOS上非常重要，手势操作移动设备的重要特征，极大的增加了移动设备使用便捷性。 iOS系统在3.2以后，为方便开发这使用一些常用的手势，提供了UIGestureRecognizer类。手势识别UIGestureRecognizer类是个抽象类，下面的子类是具体的手势，开发这可以直接使用这些手势识别。

UITapGestureRecognizer
UIPinchGestureRecognizer
UIRotationGestureRecognizer
UISwipeGestureRecognizer
UIPanGestureRecognizer
UILongPressGestureRecognizer 上面的手势对应的操作是：

Tap（点一下）Pinch（二指往內或往外拨动，平时经常用到的缩放）Rotation（旋转）Swipe（滑动，快速移动）Pan （拖移，慢速移动） LongPress（长按）

UIGestureRecognizer的继承关系如下：

2、使用手势的步骤 使用手势很简单，分为两步：

创建手势实例。当创建手势时，指定一个回调方法，当手势开始，改变、或结束时，回调方法被调用。添加到需要识别的View中。每个手势只对应一个View，当屏幕触摸在View的边界内时，如果手势和预定的一样，那就会回调方法。

ps：一个手势只能对应一个View，但是一个View可以有多个手势。 建议在真机上运行这些手势,模拟器操作不太方便，可能导致你认为手势失效。 3、Pan 拖动手势：

UIImageView *snakeImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"snake.png"]];
snakeImageView.frame = CGRectMake(50, 50, 100, 160);
UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc]
initWithTarget:self
action:@selector(handlePan:)];
[snakeImageView addGestureRecognizer:panGestureRecognizer];
[self.view setBackgroundColor:[UIColor whiteColor]];
[self.view addSubview:snakeImageView];

新建一个ImageView，然后添加手势 回调方法：

- (void) handlePan:(UIPanGestureRecognizer*) recognizer  {      CGPoint translation = [recognizer translationInView:self.view];      recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,                                     recognizer.view.center.y + translation.y);      [recognizer setTranslation:CGPointZero inView:self.view];     } 

4、Pinch缩放手势

UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc]                                               initWithTarget:self                                                   action:@selector(handlePinch:)];<p class="p1">[<span class="s1">snakeImageView</span> <span class="s2">addGestureRecognizer</span>:pinchGestureRecognizer];</p> 

5、Rotation旋转手势

    UIRotationGestureRecognizer *rotateRecognizer = [[UIRotationGestureRecognizer alloc]                                                       initWithTarget:self                                                       action:@selector(handleRotate:)];      [snakeImageView addGestureRecognizer:rotateRecognizer];      - (void) handleRotate:(UIRotationGestureRecognizer*) recognizer      {          recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);          recognizer.rotation = 0;      }  

6、添加第二个ImagView并添加手势
记住：一个手势只能添加到一个View，两个View当然要有两个手势的实例了

    - (void)viewDidLoad      {          [super viewDidLoad];          UIImageView *snakeImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"snake.png"]];          UIImageView *dragonImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"dragon.png"]];          snakeImageView.frame = CGRectMake(120, 120, 100, 160);          dragonImageView.frame = CGRectMake(50, 50, 100, 160);          [self.view addSubview:snakeImageView];          [self.view addSubview:dragonImageView];          for (UIView *view in self.view.subviews) {              UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc]                                                              initWithTarget:self                                                              action:@selector(handlePan:)];              UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc]                                                                  initWithTarget:self                                                                  action:@selector(handlePinch:)];              UIRotationGestureRecognizer *rotateRecognizer = [[UIRotationGestureRecognizer alloc]                                                               initWithTarget:self                                                               action:@selector(handleRotate:)];              [view addGestureRecognizer:panGestureRecognizer];              [view addGestureRecognizer:pinchGestureRecognizer];              [view addGestureRecognizer:rotateRecognizer];              [view setUserInteractionEnabled:YES];          }          [self.view setBackgroundColor:[UIColor whiteColor]];           }  

7、拖动(pan手势)速度(以较快的速度拖放后view有滑行的效果)
如何实现呢？
//添加拖动手势

UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGesture:)];[self.view addGestureRecognizer:panGesture];//拖动手势-(void) panGesture:(id)sender{    UIPanGestureRecognizer *panGesture = sender;    CGPoint movePoint = [panGesture translationInView:self.view];}

8.旋转手势（RotationGestureRecognizer）

//添加旋转手势UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotationGesture:)];[self.view addGestureRecognizer:rotationGesture];//旋转手势-(void)rotationGesture:(id)sender{    UIRotationGestureRecognizer *gesture = sender;    if (gesture.state==UIGestureRecognizerStateChanged)    {        _imageView.transform=CGAffineTransformMakeRotation(gesture.rotation);    }    if(gesture.state==UIGestureRecognizerStateEnded)    {        [UIView animateWithDuration:1 animations:^{            _imageView.transform=CGAffineTransformIdentity;//取消形变        }];    }}