iOS 手势与触摸

1. 响应触摸方法：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"touchesBegan");
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"touchesMoved");
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"touchesEnded");
}
//当系统事件（如内存不足、电话呼入）终止了触摸事件时响应该方法
-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"touchesCancelled");
}

2. 添加了手势的控件常需要设置的属性：
   (UILabel,UIImageVIew默认不允许用户交互)

//UILabel默认不允许用户交互，故如此设置
_lbtext.userInteractionEnabled = YES;
//设置控件为多点触控
 _lbtext.multipleTouchEnabled = YES;

3. 手势处理器 UIGestureRecognizer
   UIGestureRecognizer是所有手势控制器的基类，它提供了如下子类：

   • UITapGestureRecognizer：轻拍手势
   • UIPinchGestureRecognizer ： 捏合手势
   • UIPanGestureRecognizer ：拖拽手势
   • UISwipeGestureRecognizer ： 轻扫手势
   • UIRotationGestureRecognizer ：旋转手势
   • UILongPressGestureRecognizer ：长按手势

4. UITapGestureRecognizer 轻拍 －常用于 “加在空白处，关闭键盘”

UITapGestureRecognizer *tapGesture2 
= [[UITapGestureRecognizer alloc] initWithTarget:self    action:@selector(closeKey)];
[self.view addGestureRecognizer:tapGesture2];
-(void)closeKey{
    [self.view endEditing:YES];
}

5. UISwipeGestureRecognizer 轻扫
   特有属性： dirction：设置轻扫的方向，支持上，下，左，右四个方向。
   （设置四个方向的轻扫）

for (int i=0; i<4; i++) {
    UISwipeGestureRecognizer *swipeGesture 
    = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeHandle:)];
        [swipeGesture setDirection:1<<i];
        [self.view addGestureRecognizer:swipeGesture];
    }

-(void)swipeHandle:(UISwipeGestureRecognizer *)recognizer{
    switch (recognizer.direction) {
        case UISwipeGestureRecognizerDirectionUp:
            NSLog(@"向上滑");
            break;
        case UISwipeGestureRecognizerDirectionDown:
            NSLog(@"向下滑");
            break;
        case UISwipeGestureRecognizerDirectionRight:
            NSLog(@"向右滑");
            break;
        case UISwipeGestureRecognizerDirectionLeft:
            NSLog(@"向左滑");
            break;
        default:
            break;
    }
}

6. 拖动时候肯定有个速度，返回值就是你拖动时X和Y轴上的速度，速度是矢量，有方向。

CGPoint velocity = [(UIPanGestureRecognizer *)gestureRecognizer     velocityInView:self.view];

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参考资料：

1. 知识链接1

2. 知识链接2

3. 响应链简析