/** 1. 使用手势识别的四个步骤  1> 实例化手势识别    - (id)initWithTarget:(id)target action:(SEL)action; 2> 设置手势识别属性 3> 将手势识别附加到指定的视图    addGestureRecognizer  4> 编写监听方法  用代码创建一个UIImageView添加到视图，实验6种手势识别。 3. 手势说明  0> UIGestureRecognizer     所有手势识别的父类，不允许直接使用，可以用来自定义手势（建议大家不要挑战）     最常用的属性：     view：   发生手势的视图    state：  手势当前的状态，主要用于连续手势，对于离散手势一般不使用    1> UITapGestureRecognizer          点按手势(离散手势，其他手势都是连续手势)     属性：    numberOfTapsRequired       点击次数，单击双击    numberOfTouchesRequired    手指根数  2> UILongPressGestureRecognizer    长按手势     属性不建议修改  3> UIPanGestureRecognizer          拖动手势     属性：不常用    方法：    // 在视图中拖动的距离    - (CGPoint)translationInView:(UIView *)view;    // 在视图中拖动的速度，通常可用于模拟惯性，需要一些物理方面的计算     - (CGPoint)velocityInView:(UIView *)view;  4> UIPinchGestureRecognizer        捏合手势     属性：    scale           比例    velocity        捏合速度，不常用  5> UIRotationGestureRecognizer     旋转手势     属性    rotation        旋转角度    velocity        旋转速度，不常用  6> UISwipeGestureRecognizer        轻扫手势，通常添加到根视图上        属性    numberOfTouchesRequired     参与轻扫手势的手指根数    direction                   轻扫的方向     提示：    1) 如果要检测几个方向的轻扫，需要分别实例化几个轻扫手势    2) 轻扫手势虽然是连续手势，但是不需要去处理UIGestureRecognizerStateChanged状态        因为是在手指离开屏幕后，该手势才被识别的  其他技巧     在if语句中，将常量放置在判断条件的左侧，可以避免因为只写了 = 出现警告，置之不理的情况！ */- (void)viewDidLoad{    [super viewDidLoad];        // 0. 实例化UIImageView    UIImage *image = [UIImage imageNamed:@"001"];    UIImageView *imageView = [[UIImageView alloc]initWithImage:image];        [imageView setFrame:CGRectMake(10, 100, 300, 196)];    [self.view addSubview:imageView];        [imageView setUserInteractionEnabled:YES];        // 1. 添加点按手势    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tap:)];    // 定义双击    tap.numberOfTapsRequired = 2;    [imageView addGestureRecognizer:tap];        // 2. 添加长按手势    UILongPressGestureRecognizer *longTap = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longTap:)];    [imageView addGestureRecognizer:longTap];        // 3. 拖动手势    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];        [imageView addGestureRecognizer:pan];        // 4. 捏合手势    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinch:)];    [imageView addGestureRecognizer:pinch];        // 5. 旋转手势    UIRotationGestureRecognizer *rotation = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];    [imageView addGestureRecognizer:rotation];        // 6. 轻扫手势    // 如果要做清扫手势，需要分别实例化4个方向的手势    UISwipeGestureRecognizer *swipeUp = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];        swipeUp.direction = UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown | UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionRight;        [self.view addGestureRecognizer:swipeUp];    //    UISwipeGestureRecognizer *swipeDown = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];//    swipeDown.direction = UISwipeGestureRecognizerDirectionDown;//    [self.view addGestureRecognizer:swipeDown];//    //    UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];//    swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;//    [self.view addGestureRecognizer:swipeLeft];////    UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];//    swipeRight.direction = UISwipeGestureRecognizerDirectionRight;//    [self.view addGestureRecognizer:swipeRight];}#pragma mark - 点按手势- (void)tap:(UITapGestureRecognizer *)recognizer{    // 双击放大图片    UIImageView *imageView = (UIImageView *)recognizer.view;    [UIView animateWithDuration:0.8f animations:^{        [imageView setTransform:CGAffineTransformScale(imageView.transform, 2.0, 2.0)];    } completion:^(BOOL finished) {        [UIView animateWithDuration:0.5f animations:^{            [imageView setTransform:CGAffineTransformScale(imageView.transform, 0.5, 0.5)];        }];    }];}#pragma mark - 长按手势- (void)longTap:(UILongPressGestureRecognizer *)recognizer{    NSLog(@"长按");    // 长按旋转图片    // 开始长按    // 在形变时，iOS采取就近原则旋转，如果不能按照希望的方向旋转，可以增加一些修正值，例如0.01    // 直接通过形变属性，要实现一次性转一圈，比较困难，可以分两次进行    if (UIGestureRecognizerStateBegan == recognizer.state) {        [UIView animateWithDuration:0.8f animations:^{            [recognizer.view setTransform:CGAffineTransformRotate(recognizer.view.transform, M_PI - 0.01)];        }];    } else if (UIGestureRecognizerStateEnded == recognizer.state) {        [UIView animateWithDuration:0.8f animations:^{            [recognizer.view setTransform:CGAffineTransformRotate(recognizer.view.transform, M_PI - 0.01)];        } completion:^(BOOL finished) {            // 清除所有的形变属性            [recognizer.view setTransform:CGAffineTransformIdentity];        }];    }}#pragma mark - 拖动- (void)pan:(UIPanGestureRecognizer *)recognizer{    CGPoint translation = [recognizer translationInView:self.view];        // 让图像根据手指移动    if (UIGestureRecognizerStateChanged == recognizer.state) {        // 形变参数，有Make的时候，是相对初始位置计算的        // 没有Make是递增修改形变的        [recognizer.view setTransform:CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y)];                // 拖动手指中的平移距离是相对于初始位置，如果使用CGAffineTransformTranslate累加形变方法        // 需要在每次位移之后，重置recognizer的位移量，就是将位移量清零        [recognizer setTranslation:CGPointZero inView:recognizer.view];    }}#pragma mark - 捏合- (void)pinch:(UIPinchGestureRecognizer *)recognizer{    // 调整图像的显示比例    if (UIGestureRecognizerStateChanged == recognizer.state) {                // 等比例缩放        [recognizer.view setTransform:CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale)];                // 在设置累加形变参数时，需要充值手势的缩放比例        recognizer.scale = 1.0f;    }}#pragma mark - 旋转- (void)rotate:(UIRotationGestureRecognizer *)recognizer{    if (UIGestureRecognizerStateChanged == recognizer.state) {        recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);                // 重置旋转量        recognizer.rotation = 0.0f;    }}#pragma mark - 轻扫- (void)swipe:(UISwipeGestureRecognizer *)recognizer{    //NSLog(@"%d", recognizer.direction);    if (UISwipeGestureRecognizerDirectionDown == recognizer.direction) {        NSLog(@"向下");    } else if (UISwipeGestureRecognizerDirectionUp == recognizer.direction) {        NSLog(@"向上");    } else if (UISwipeGestureRecognizerDirectionLeft == recognizer.direction) {        NSLog(@"向左");    } else if (UISwipeGestureRecognizerDirectionRight == recognizer.direction) {        NSLog(@"向右");    }}