iOS学习之手势

UIGestureRecognizer

为了完成手势识别，必须借助于手势识别器—-UIGestureRecognizer，利用UIGestureRecognizer，能轻松识别用户在某个view上面做的一些常见手势UIGestureRecognizer是一个抽象类，定义了所有手势的基本行为，使用它的子类才能处理具体的手势，要实现<UIGestureRecognizerDelegate>

手势状态：

typedef NS_ENUM(NSInteger, UIGestureRecognizerState) {

     UIGestureRecognizerStatePossible,   // 尚未识别是何种手势操作（但可能已经触发了触摸事件），默认状态

     UIGestureRecognizerStateBegan,      // 手势已经开始，此时已经被识别，但是这个过程中可能发生变化，手势操作尚未完成

    UIGestureRecognizerStateChanged,    // 手势状态发生转变

     UIGestureRecognizerStateEnded,      // 手势识别操作完成（此时已经松开手指）

     UIGestureRecognizerStateCancelled,  // 手势被取消，恢复到默认状态

     UIGestureRecognizerStateFailed,     // 手势识别失败，恢复到默认状态

     UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded // 手势识别完成，同UIGestureRecognizerStateEnded };

常用的六种手势：

1. 轻击手势（TapGestureRecognizer）
2. 轻扫手势 （SwipeGestureRecognizer）
3. 长按手势（LongPressGestureRecognizer）
4. 拖动手势（PanGestureRecognizer）
5. 捏合手势（PinchGestureRecognizer）
6. 旋转手势（RotationGestureRecognizer）

1． 轻击手势（TapGestureRecognizer）

) 初始化轻击手势识别器对象

UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] init];

 ) 设置手势识别器对象的具体属性
// 连续敲击2次
tap.numberOfTapsRequired = ;
// 需要2根手指一起敲击
tap.numberOfTouchesRequired = ;
//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:)];
) 代理
 tap.delegate = self;
//轻击手势触发方法
-(void) tapIconView:(UITapGestureRecognizer *)sender
{

    NSLog(@"我用两只手指敲击屏幕成功了！");
}
#pragma mark - 代理方法

/**

*  当点击view的时候,会先调用这个方法

 */

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch

{
    CGPoint pos = [touch locationInView:touch.view];

    if (pos.x <= self.iconView.frame.size.width * 0.5) {

        return YES;

    }
    return NO;

}

2． 轻扫手势 （SwipeGestureRecognizer）

1. 初始化轻扫手势识别器对象
   UISwipeGestureRecognizer *swipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeGesture:)];
   
   //设置轻扫的向右方向
   
   swipeGesture.direction = UISwipeGestureRecognizerDirectionRight; //向右
   
   [self.view addGestureRecognizer:swipeGesture];
   
   UISwipeGestureRecognizer *swipeGestureLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeGesture:)];
   
   //设置轻扫的方向
   
   swipeGestureLeft.direction = UISwipeGestureRecognizerDirectionLeft; //向左
   
   [self.view addGestureRecognizer:swipeGestureLeft];
   
   //轻扫手势触发方法
   
   -(void)swipeGesture:(id)sender
   
   {
   
   UISwipeGestureRecognizer *swipe = sender;
   
   if (swipe.direction == UISwipeGestureRecognizerDirectionLeft)
   
   {
   
   //向左轻扫
   
   }
   
   if (swipe.direction == UISwipeGestureRecognizerDirectionRight)
   
   {
   
   //向右轻扫
   
   }
   
   } 

3． 长按手势（LongPressGestureRecognizer）

初始化轻扫手势识别器对象

UILongPressGestureRecognizer *longPressGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressGesture:)];

//设置长按时间

longPressGesture.minimumPressDuration = 0.5;

[self.view addGestureRecognizer:longPressGesture];

//长按手势触发方法

-(void)longPressGesture:(id)sender

{

 UILongPressGestureRecognizer *longPress = sender;

 if (longPress.state == UIGestureRecognizerStateBegan)

 {

 //your code

 }

}

说明：长按手势的常用状态如下

开始：UIGestureRecognizerStateBegan

改变：UIGestureRecognizerStateChanged

结束：UIGestureRecognizerStateEnded

取消：UIGestureRecognizerStateCancelled

失败：UIGestureRecognizerStateFailed

4． 拖动手势（PanGestureRecognizer）

初始化轻扫手势识别器对象

UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGesture:)];

[self.view addGestureRecognizer:panGesture];

//拖动手势触发方法

-(void) panGesture:(id)sender

{
    UIPanGestureRecognizer *panGesture = sender;

    CGPoint movePoint = [panGesture translationInView:self.view];

    //your code

}

5． 捏合手势（PinchGestureRecognizer）

初始化轻扫手势识别器对象

UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGesture:)];

[self.view addGestureRecognizer:panGesture];
//拖动手势触发方法

-(void) panGesture:(id)sender

{

    UIPanGestureRecognizer *panGesture = sender;

    CGPoint movePoint = [panGesture translationInView:self.view];

    //your code
}

6． 旋转手势（RotationGestureRecognizer）

初始化轻扫手势识别器对象

UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotationGesture:)];

[self.view addGestureRecognizer:rotationGesture];

//旋转手势触发方法

-(void)rotationGesture:(id)sender

{

UIRotationGestureRecognizer *gesture = sender;

if (gesture.state==UIGestureRecognizerStateChanged)

{

_imageView.transform=CGAffineTransformMakeRotation(gesture.rotation);

}

if(gesture.state==UIGestureRecognizerStateEnded)

{

[UIView animateWithDuration: animations:^{

_imageView.transform=CGAffineTransformIdentity;//取消形变

}];

}

}