iOS中手势的应用1. 四类事件的主要方法2. 响应者链3. 手势识别功能（Gesture Recognizer）4. 手势的使用

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

-(void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event;
-(void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event;
-(void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event;

-(void)remoteControlReceivedWithEvent:(UIEvent *)event;

-(void)pressesBegan:(NSSet *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);

-(void)pressesChanged:(NSSet *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);

-(void)pressesEnded:(NSSet *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);

-(void)pressesCancelled:(NSSet *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);

//判断是否能够成为第一响应者
- (BOOL)canBecomeFirstResponder

//响应者放弃第一响应者身份
- (BOOL)resignFirstResponder
- (BOOL)canResignFirstResponder

//创建手势识别器对象
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] init];

//设置手势识别器对象的具体属性,例如连续敲击2次
tap.numberOfTapsRequired = 2;
// 需要2根手指一起敲击
tap.numberOfTouchesRequired = 2;

//添加手势识别器到对应的view上
[self.iconView addGestureRecognizer:tap];

//监听手势的触发
[tap addTarget:self action:@selector(tapIconView:)];

typedef NS_ENUM(NSInteger, UIGestureRecognizerState) {
    // 没有触摸事件发生，所有手势识别的默认状态
    UIGestureRecognizerStatePossible,
    // 一个手势已经开始但尚未改变或者完成时
    UIGestureRecognizerStateBegan, （类似于 touchesBegan）
    // 手势状态改变
    UIGestureRecognizerStateChanged, （类似于 touchesMoved）
    // 手势完成
    UIGestureRecognizerStateEnded, （类似于 touchesEnded）
    // 手势取消，恢复至Possible状态
    UIGestureRecognizerStateCancelled, (比如手指按下按钮，然后从其他地方抬起)
    // 手势失败，恢复至Possible状态
    UIGestureRecognizerStateFailed,
    // 识别到手势识别
    UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
};

- (void)addLongPressGesture
{
    //创建长按手势识别并添加监听事件
    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
    //    给图片添加长按手势
    [self.imageView addGestureRecognizer:longPress];
}

//识别到长按手势后回调的方法
- (void)longPress:(UILongPressGestureRecognizer *)recognizer
{
    // 判断手势的状态，长按手势一定要判断状态，否则方法会在手势开始和结束时分别调用！方法会被调用两次！
    if (recognizer.state == UIGestureRecognizerStateBegan) {
        //动画  改变图片的透明度
        [UIView animateWithDuration:0.5 animations:^{
            self.imageView.alpha = 0.5;
        } completion:^(BOOL finished) {
            [UIView animateWithDuration:0.5 animations:^{
                self.imageView.alpha = 1.0;
            }];
        }];
    }
}

- (void)addSwipeGesture
{
    // 如果要监听多个轻扫方向，需要添加多个轻扫手势
    // 轻扫手势默认支持向右的扫动方向
    
    //创建轻扫手势识别并添加监听事件（默认是向右扫动）
    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];
    
    //创建轻扫手势识别并添加监听事件
    UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];
    //direction 方向  向左轻扫
    swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
    
    /**
     UISwipeGestureRecognizerDirectionRight  向右轻扫(默认)不设轻扫方向 就是向右
     UISwipeGestureRecognizerDirectionLeft  向左轻扫
     UISwipeGestureRecognizerDirectionUp    向上轻扫
     UISwipeGestureRecognizerDirectionDown  向下轻扫
     */
    
    
    // 因为轻扫手势要求用户比较放松的扫动，因此最好不要将此手势添加到某一个视图上，会局限用户的操作
    //    添加手势
    [self.view addGestureRecognizer:swipe];
    [self.view addGestureRecognizer:swipeLeft];
}

//识别到轻扫手势后回调的方法
- (void)swipe:(UISwipeGestureRecognizer *)recognizer
{
    //当前获取中心位置
    CGPoint from = self.imageView.center;
    //目标
    CGPoint to;
    //向左轻扫
    if (recognizer.direction == UISwipeGestureRecognizerDirectionLeft) {
        to = CGPointMake(-from.x, from.y);
    } else {//向右轻扫
        to = CGPointMake(3 * from.x, from.y);
    }
    //动画移动图片
    [UIView animateWithDuration:0.5 animations:^{
        self.imageView.center = to;
    }completion:^(BOOL finished) {
        [UIView animateWithDuration:0.5 animations:^{
            self.imageView.center = from;
        }];
    }];
}

- (void)addPanGesture
{
    //创建拖动手势 并添加手势的监听事件
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
    
    //添加手势
    [self.imageView addGestureRecognizer:pan];
}
//识别到拖动手势后回调的方法
- (void)pan:(UIPanGestureRecognizer *)recognizer
{
    //获取手指按在图片上的位置  以图片左上角为原点
    CGPoint translation = [recognizer translationInView:self.imageView];
    //    移动图片
    recognizer.view.transform = CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y);
    //给平移复位 因为他是在原有基础上当前递增平移 如果不复位  或清空他会越变越大
    [recognizer setTranslation:CGPointZero inView:self.imageView];
}

- (void)addPinchGesture
{
    //创建缩放（捏合）手势 并添加手势的监听事件
    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinch:)];
    //设置控制器为缩放手势的代理  可以实现同时识别两个手势
    pinch.delegate = self;
    [self.imageView addGestureRecognizer:pinch];
}
//识别到 缩放（捏合）手势后回调的方法
- (void)pinch:(UIPinchGestureRecognizer *)recognizer
{
    //绽放图片
    recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale);
    
    //将缩放比例复位
    recognizer.scale = 1.0;
}

- (void)addRotateGesture
{
    //创建缩放 旋转并添加手势的监听事件
    UIRotationGestureRecognizer *rotate = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];
    //设置控制器为缩放手势的代理  可以实现同时识别两个手势
    rotate.delegate = self;
    //    添加手势
    [self.imageView addGestureRecognizer:rotate];
}
//识别到旋转手势后的回调方法
- (void)rotate:(UIRotationGestureRecognizer *)recognizer
{
    //图片旋转
    recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);
    
    //将手势识别的旋转角度复位
    recognizer.rotation = 0.0;  //非常重要  角度也会叠加
}

- (void)addTapGesture
{
    //创建缩放点按（单击，点击）并添加手势的监听事件
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tap)];
    //    添加手势
    [self.imageView addGestureRecognizer:tapGesture];
    
}
//识别到手势后的回调方法
- (void)tap
{
    NSLog(@"点我了");
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}