iOS－同时识别多种触摸事件，触摸事件不共享问题

触摸事件不共享问题

在iOS中，当某个触摸事件被UIGestureRecongnizer对象识别出来，就会“吃掉”所有相关的触摸事件，导致其他UIGestureRecongnizer对象无法识别出这个事件

解决方法：代理

1.UIView的子类

 

self.panGestureRecognizer=

        [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(pan:)];

        self.panGestureRecognizer.delegate = self;

        self.panGestureRecognizer.cancelsTouchesInView=NO;

        [self addGestureRecognizer:self.panGestureRecognizer];

其中 cancelsTouchesInView 默认设置为YES，设置为YES的时候，该对象在识别出某个手势后，会“吃掉”跟手势有关的UITouch对象，这样对象所依附的UIView对象将无法接受到相关 Responder消息。例如，touchBegin:withEven

2.实现

gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer: 方法

当gesture recognizer 识别出手势，同时其他gesture recognizer也识别出手势，geesture recongnizer 会向协议代理发送消息，如果该方法返回YES，recognizer 会跟其他gesture recognizer 共享手势

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

{

    if (gestureRecognizer==self.panGestureRecognizer) {

        return  YES;

    }

    return NO;

}

状态

• UIGestureRecognizerStateBegan: 当手指移动时，gestureRecognizer就会进入此状态，持续向target发送消息(action)
• UIGestureRecognizerStateChanged：当手指移动时，gestureRecognizer就会进入此状态，持续向target发送消息(action)
• UIGestureRecognizerStateEnded: 当手指离开屏幕的时候，gestureRecognizer对象会切换至结束状态，向target发送最后一次消息