iOS基础篇（十七）——UIGestureRecognizer用法

UIGestureRecognizer（手势识别）在iOS 中非常重要，他极大地提高了移动设备的使用便捷性；

在3.2之前是主要使用的是由UIResponder而来的如下4种方式：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
 - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

但是由于这种方式需要自己计算做不同的手势分辨，实在麻烦。

在3.2 以后，提供了一些常用的手势（UIGestureRecognizer 的子类），开发者可以直接使用他们进行手势操作。

1、拍击——UITapGestureRecognizer

2、向里或向外捏——UIPinchGestureRecognizer

3、摇动或者拖拽——UIPanGestureRecognizer

4、擦碰——UISwipeGestureRecognizer

5、旋转——UIRotationGestureRecognizer 

6、长按——UILongPressGestureRecognizer 

每个手势识别器的用法都差不多，以UITapGestureRecognizer为例：

     //创建手势识别器对象并监听手势的触发
     UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapAction:)];
     //连续敲击次数
     tap.numberOfTapsRequired = ;
     //需要两根手指一起敲击
     tap.numberOfTouchesRequired = ;
     //添加手势到指定的view上
     [self.view addGestureRecognizer:tap];

敲击实例：

1、UITapGestureRecognizer 拍击

 //创建手势识别器对象并监听手势的触发
     UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapAction:)];
     //连续敲击次数
     tap.numberOfTapsRequired = ;
     //需要两根手指一起敲击
     tap.numberOfTouchesRequired = ;
     //添加手势到指定的view上
     [self.view addGestureRecognizer:tap];

 - (void)tapAction:(UITapGestureRecognizer*)tapGesture{

     NSLog(@"我敲击了屏幕");

     CGPoint point = [tapGesture locationInView:self.view];
     NSLog(@"tapAction:%f,%f",point.x,point.y);
 }

输出：

2、UIPinchGestureRecognizer  向里或向外捏

     UIPinchGestureRecognizer *Pinch =[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(PinchAction:)];
     Pinch.delegate = self;
     [imageView addGestureRecognizer:Pinch];

 - (void)PinchAction:(UIPinchGestureRecognizer*)pinchGesture{
         pinchGesture.view.transform = CGAffineTransformScale(pinchGesture.view.transform, pinchGesture.scale, pinchGesture.scale);
         pinchGesture.scale = ;
 }

3、UIPanGestureRecognizer  摇动或者拖拽

//先放置一张图片实施拖拽

imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"u=3971024035,4095552302&fm=21&gp=0"]];

    [imageView setFrame:(CGRect){50,50,100,100}];

    [self.view addSubview:imageView];

    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAction:)];
    pan.delegate = self;
    [self.view addGestureRecognizer:pan];

    //设置触发拖拽的最少触摸点,默认为1
    pan.minimumNumberOfTouches = ;
    //设置触发拖拽的最多触摸点
    pan.maximumNumberOfTouches = ;

- (void)panAction:(UIPanGestureRecognizer *)panGesture{
    CGPoint point = [panGesture locationInView:self.view];

    NSLog(@"panAction:(%f, %f)",point.x, point.y);
    imageView.center = point;

    if (panGesture.state==UIGestureRecognizerStateBegan) {
        NSLog(@"panAction StateBegan:(%f,%f)", point.x, point.y);
    }

    if (panGesture.state==UIGestureRecognizerStateChanged) {
        NSLog(@"panAction StateChanged:(%f,%f)", point.x, point.y);
    }

    if (panGesture.state==UIGestureRecognizerStateEnded) {
        NSLog(@"panAction StateEnded:(%f,%f)", point.x, point.y);
    }

}

输出：

4、UISwipeGestureRecognizer  擦碰

     UISwipeGestureRecognizer *leftSwipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(SwipeAction:)];
     [self.view addGestureRecognizer:leftSwipeGesture];
     leftSwipeGesture.direction = UISwipeGestureRecognizerDirectionLeft;

     UISwipeGestureRecognizer *rightSwipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(SwipeAction:)];
     [self.view addGestureRecognizer:rightSwipeGesture];
     rightSwipeGesture.direction = UISwipeGestureRecognizerDirectionRight;

 - (void)SwipeAction:(UISwipeGestureRecognizer*)swipeGesture{
     if (swipeGesture.direction==UISwipeGestureRecognizerDirectionLeft) {
         NSLog(@"swipeGesture:Left");
     }
     if (swipeGesture.direction==UISwipeGestureRecognizerDirectionRight) {
         NSLog(@"swipeGesture:Right");
     }
 }

输出：

5、UIRotationGestureRecognizer  旋转

 UIRotationGestureRecognizer *rotations = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotationAction:)];
     rotations.delegate = self;
     rotation = ;
     [self.view addGestureRecognizer:rotations];

 - (void)rotationAction:(UIRotationGestureRecognizer*)rotationGesture{
     imageView.transform = CGAffineTransformMakeRotation(rotation+rotationGesture.rotation);

     if (rotationGesture.state==UIGestureRecognizerStateEnded) {
         rotation += rotationGesture.rotation;
     }

 }

6、UILongPressGestureRecognizer  长按

     UILongPressGestureRecognizer *longp = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longAction:)];
     [self.view addGestureRecognizer:longp];

     longp.numberOfTouchesRequired = ;
     //长按时间为2秒
     longp.minimumPressDuration = ;
     //允许15秒中运动
     longp.allowableMovement = ;

 - (void)longAction:(UILongPressGestureRecognizer *)longPress{
     CGPoint point = [longPress locationInView:self.view];
     imageView.center = point;

     if(longPress.state == UIGestureRecognizerStateBegan){
         NSLog(@"longAction StateBegan: (%f, %f)", point.x, point.y);
     }

     if(longPress.state == UIGestureRecognizerStateEnded){
         NSLog(@"longAction StateEnded: (%f, %f)", point.x, point.y);
     }
 }

输出：