iOS开发之手势识别实例

2020-01-18 18:08:51王振洲

在对应的回调方法中添加相应的方法(当手势开始时执行):


//常摁手势触发方法
-(void)longPressGesture:(id)sender
{
 UILongPressGestureRecognizer *longPress = sender;
 if (longPress.state == UIGestureRecognizerStateBegan)
 {
  UIAlertView *alter = [[UIAlertView alloc] initWithTitle:@"提示" message:@"长按触发" delegate:nil cancelButtonTitle:@"取消" otherButtonTitles: nil];
  [alter show];
 }
}

代码说明:手势的常用状态如下

开始:UIGestureRecognizerStateBegan 改变:UIGestureRecognizerStateChanged 结束:UIGestureRecognizerStateEnded 取消:UIGestureRecognizerStateCancelled 失败:UIGestureRecognizerStateFailed

3.轻扫手势(SwipeGestureRecognizer)

在初始化轻扫手势的时候得指定轻扫的方向,上下左右。 如果要要添加多个轻扫方向,就得添加多个轻扫手势,不过回调的是同一个方法。

添加轻扫手势,一个向左一个向右,代码如下:


//添加轻扫手势
 UISwipeGestureRecognizer *swipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeGesture:)];
 //设置轻扫的方向
 swipeGesture.direction = UISwipeGestureRecognizerDirectionRight; //默认向右
 [self.view addGestureRecognizer:swipeGesture];
  
 //添加轻扫手势
 UISwipeGestureRecognizer *swipeGestureLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeGesture:)];
 //设置轻扫的方向
 swipeGestureLeft.direction = UISwipeGestureRecognizerDirectionLeft; //默认向右
 [self.view addGestureRecognizer:swipeGestureLeft];

回调方法如下:


//轻扫手势触发方法
-(void)swipeGesture:(id)sender
{
 UISwipeGestureRecognizer *swipe = sender;
 if (swipe.direction == UISwipeGestureRecognizerDirectionLeft)
 {
  //向左轻扫做的事情
 }
 if (swipe.direction == UISwipeGestureRecognizerDirectionRight)
 {
  //向右轻扫做的事情
 }
}

4.捏合手势(PinchGestureRecognizer)

捏合手势初始化


//添加捏合手势
UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchGesture:)];
[self.view addGestureRecognizer:pinchGesture];

捏合手势要触发的方法(放大或者缩小图片):


////捏合手势触发方法
-(void) pinchGesture:(id)sender
{
  UIPinchGestureRecognizer *gesture = sender;
  
 //手势改变时
 if (gesture.state == UIGestureRecognizerStateChanged)
 {
  //捏合手势中scale属性记录的缩放比例
  _imageView.transform = CGAffineTransformMakeScale(gesture.scale, gesture.scale);
 }
  
 //结束后恢复
 if(gesture.state==UIGestureRecognizerStateEnded)
 {
  [UIView animateWithDuration:0.5 animations:^{
   _imageView.transform = CGAffineTransformIdentity;//取消一切形变
  }];
 }
}