iOS – 几种常见手势的简单使用[原创]

1、UIGestureRecognizer 介绍

手势识别在 iOS 中非常重要，他极大地提高了移动设备的使用便捷性。

iOS 系统在 3.2 以后，他提供了一些常用的手势（UIGestureRecognizer 的子类），开发者可以直接使用他们进行手势操作。

• UIPanGestureRecognizer（拖动）
• UIPinchGestureRecognizer（捏合）
• UIRotationGestureRecognizer（旋转）
• UITapGestureRecognizer（点按）
• UILongPressGestureRecognizer（长按）
• ​UISwipeGestureRecognizer（轻扫）

另外，可以通过继承 UIGestureRecognizer 类，实现自定义手势（手势识别器类）。

使用手势很简单，分为三步：

1. 创建手势识别器对象实例。创建时，指定一个回调方法，当手势开始，改变、或结束时，执行回调方法。
2. 设置手势识别器对象实例的相关属性（可选部分）
3. 添加到需要识别的 View 中。每个手势只对应一个 View，当屏幕触摸在 View 的边界内时，如果手势和预定的一样，那就会执行回调方法。

值得注意的地方：

一个手势只能对应一个 View，但是一个 View 可以有多个手势。建议在真机上测试这些手势，模拟器操作不太方便，可能导致认为手势失效的情况。（

• 平移(Pan)、旋转(Rotation)、捏合(Pinch)事件都是需要进行清零操作。
• 捏合手势不能和旋转手势一起使用。

UIGestureRecognizer 的继承关系如下：

2、具体的使用步骤

2.1.点按手势：UITapGestureRecognizer

首先要声明UIGestureRecognizerDelegate代理的方法，继承代理。

添加点按手势：

//创建点按手势
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc ]initWithTarget:self action:@selector(tap)];
    //继承代理
    tap.delegate = self ;
    //添加手势
    [self.imagView addGestureRecognizer:tap] ;

继承代理：值得注意的是只有点按手势有代理方法

//继承代理
tap.delegate = self ;

实现点按手势的代理方法：

//是否允许接受手指
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
    //判断点在图片的左边还是右边
    //在左边返回YES，反之在NO
    //1.获取当前的点
    CGPoint curP = [touch locationInView:self.imagView] ;
    if (curP.x > self.imagView.bounds.size.width * 0.5) {
        return YES ;
    }else{
        return NO ;
    }
}

其他的代理方法：

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer;

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer;

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer ;

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldBeRequiredToFailByGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer ;

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

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceivePress:(UIPress *)press

2.2.长按手势：UILongPressGestureRecognizer

添加长按手势：

UILongPressGestureRecognizer *longP = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPress:)] ;
    [self.view addGestureRecognizer:longP] ;

实现长按手势的方法:

-(void)longPress:(UILongPressGestureRecognizer*)longP{    
//通过UILongPressGestureRecognizer的state属性来完成细节操作   
 /*     UIGestureRecognizerStateBegan,     UIGestureRecognizerStateChanged,     UIGestureRecognizerStateEnded,     UIGestureRecognizerStateCancelled,          UIGestureRecognizerStateFailed,     UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded     */       
 if(longP.state== UIGestureRecognizerStateBegan) {        
NSLog(@"UIGestureRecognizerStateBegan") ;    }
elseif(longP.state== UIGestureRecognizerStateChanged){        
NSLog(@"UIGestureRecognizerStateChanged") ;    }elseif(longP.state== UIGestureRecognizerStateEnded){        
NSLog(@"UIGestureRecognizerStateEnded") ;    
}    
NSLog(@"%s",__func__) ;}

UILongPressGestureRecognizer的不同状态下的枚举类型：

1 typedef NS_ENUM(NSInteger, UIGestureRecognizerState) {
2     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
3     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
4     UIGestureRecognizerStateChanged,    // 手势状态发生转变
5     UIGestureRecognizerStateEnded,      // 手势识别操作完成（此时已经松开手指）
6     UIGestureRecognizerStateCancelled,  // 手势被取消，恢复到默认状态
7     UIGestureRecognizerStateFailed,     // 手势识别失败，恢复到默认状态
8     UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded // 手势识别完成，同UIGestureRecognizerStateEnded
9 };

2.3.轻扫手势：UISwipeGestureRecognizer

添加轻扫手势：

//添加轻扫手势    UISwipeGestureRecognizer*swipeGes = [[UISwipeGestureRecognizeralloc]initWithTarget:selfaction:@selector(swipe:)] ;

注意点：轻扫手势默认是允许向右轻扫，可以通过swipeGes.direction属性来更改

//默认是向右轻扫
    //可以设置轻扫的方向(注意：只能左对右 或者上对下 不能左对上下)
    /*
     UISwipeGestureRecognizerDirectionRight = 1 << 0,
     UISwipeGestureRecognizerDirectionLeft  = 1 << 1,
     UISwipeGestureRecognizerDirectionUp    = 1 << 2,
     UISwipeGestureRecognizerDirectionDown  = 1 << 3
     */
    //⚠️：一个轻扫手势只能对应一个方向，上面设置了多个方向，调用的方法也只能是一个结果。
   swipeGes.direction = UISwipeGestureRecognizerDirectionRight ;
   [self.imagView addGestureRecognizer:swipeGes] ;

添加手势
UISwipeGestureRecognizer *swipeGes1 = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipe:)] ;

实现方法：

-(void)swipe:(UISwipeGestureRecognizer *)swipeGes{
    
    if (swipeGes.direction == UISwipeGestureRecognizerDirectionLeft) {
        NSLog(@"UISwipeGestureRecognizerDirectionLeft") ;
    }else if (swipeGes.direction == UISwipeGestureRecognizerDirectionRight){
        NSLog(@"UISwipeGestureRecognizerDirectionRight") ;
    }
    
    if (swipeGes.state == UIGestureRecognizerStateBegan){
        NSLog(@"swipeGes.state == UIGestureRecognizerStateBegan") ;
    }else if (swipeGes.state == UIGestureRecognizerStateEnded){
        NSLog(@"swipeGes.state == UIGestureRecognizerStateEnded") ;
    }
//    NSLog(@"%s",__func__) ;
    
}

2.4.平移手势：UIPanGestureRecognizer

添加平移手势：

//添加平移手势
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(pan:)] ;
    [self.imagView addGestureRecognizer:pan] ;

实现方法：值得注意的是：要进行清零操作 : [panGes setTranslation:CGPointMake(0, 0)]

-(void)pan:(UIPanGestureRecognizer *)panGes{
    CGPoint point = [panGes translationInView:self.imagView] ;
    NSLog(@"%@",NSStringFromCGPoint(point)) ;
    
    //相对于原点（错误做法）
//    self.imagView.transform = CGAffineTransformMakeTranslation(point.x, point.y) ;
    //相对于每次移动的点
    self.imagView.transform = CGAffineTransformTranslate(self.imagView.transform, point.x, point.y) ;
    
    //关键操作：清零操作
//    CGPointMake(0, 0) == CGPointZero
    [panGes setTranslation:CGPointMake(0, 0) inView:self.imagView] ;
}

2.5.旋转手势：UIRotationGestureRecognizer

添加旋转手势：

-(void)rota{
    //添加旋转手势
    UIRotationGestureRecognizer *rotation = [[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotation:)] ;
    [self.view addGestureRecognizer:rotation] ;
}
-(void)rotation:(UIRotationGestureRecognizer *)rotationGes{
    //获取旋转的角度（已经是弧度了）
    //相对于最原始的y弧度
    CGFloat rotation = rotationGes.rotation ;
    self.imagView.transform = CGAffineTransformRotate(self.imagView.transform, rotation) ;
    //重要部分 : 清零操作
    [rotationGes setRotation:0] ;
}

2.6.捏合手势：UIPinchGestureRecognizer

#pragma mark - 创建捏合手势
-(void)pinch{
    //创建捏合手势
    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(pinch:)] ;
    
    [self.imagView addGestureRecognizer:pinch] ;
}
-(void)pinch:(UIPinchGestureRecognizer *)pinchGes{
    //获取放大和缩放比例
    //相对于原始的比例而言
    CGFloat scale = pinchGes.scale ;
    self.imagView.transform = CGAffineTransformScale(self.imagView.transform, scale, scale) ;
    //清零操作
    [pinchGes setScale:1] ;
}

返回YES表示同时支持识别多个手势

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

转载时请注明出处及相应链接，本文永久地址：https://blog.yayuanzi.com/25012.html

微信打赏

支付宝打赏

感谢您对作者Annwn的打赏，我们会更加努力！    如果您想成为作者，请点我