touchesBegan和touchesMoved

Question

所以这里有个奇怪的问题。我有一个响应touchesMoved: & touchesBegan:的UIImageView，它工作得很好。我遇到的主要问题是，如果你把手指放在image1上，然后把手指放在image1上，你就会用另一根手指按image2。

我希望能够在同时推送两个图像时使用多点触摸，而不是一遍又一遍地发射它们。我必须添加一些东西来阻止这种情况的发生。

代码：

    -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSSet *allTouches = [event allTouches]; 
    for (UITouch *touch in allTouches) 
    { 
        CGPoint location = [touch locationInView:touch.view];
        if(CGRectContainsPoint(image1.frame, location) && lastButton != image1) {
            //Play Sound
            NSString *path = [[NSBundle mainBundle] pathForResource:@"sound1" 
                                                             ofType:@"wav"];
            SystemSoundID soundID;
            AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:path]
                                             , &soundID);
            AudioServicesPlaySystemSound (soundID); 
            //
            lastButton = image1;
        }
        if(CGRectContainsPoint(image2.frame, location) && lastButton != image2) {
            //Play Sound
            NSString *path = [[NSBundle mainBundle] pathForResource:@"sound2" 
                                                             ofType:@"wav"];
            SystemSoundID soundID;
            AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:path]
                                             , &soundID);
            AudioServicesPlaySystemSound (soundID); 
            //
            lastButton = image2;
        }

    }

而对于touchesMoved：

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint location = [touch locationInView:touch.view];
        if(CGRectContainsPoint(image1.frame, location) && lastButton != image1) {
            //Play Sound
            NSString *path = [[NSBundle mainBundle] pathForResource:@"sound1" 
                                                             ofType:@"wav"];
            SystemSoundID soundID;
            AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:path]
                                             , &soundID);
            AudioServicesPlaySystemSound (soundID); 
            //
            lastButton = image1;
        }
        if(CGRectContainsPoint(image2.frame, location) && lastButton != image2) {
            //Play Sound
            NSString *path = [[NSBundle mainBundle] pathForResource:@"sound2" 
                                                             ofType:@"wav"];
            SystemSoundID soundID;
            AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:path]
                                             , &soundID);
            AudioServicesPlaySystemSound (soundID); 
            //
            lastButton = image2;
        }

    }

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    lastButton = nil;
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
    [self touchesEnded:touches withEvent:event];
}

所以我只需要这样做，如果我按住其中一个图像，然后按下另一个图像，然后再松开它，再按下它，它就会停止发射我按下的第一个图像。

Answer 1

所有涉及到的视图都将接受所有的处理(在Jason提到的NSSet中)。这取决于每个视图(也就是说，取决于您)选择您感兴趣的视图。因此，您必须检查每个触摸是否在视图的限制内，并尝试将触摸与上一次接收的触摸相关联。例如，由于你在一个集合中获得了触点，所以你不能依靠它们的顺序来计算它们移动了多少。您必须保存最后一次触摸的坐标，并选择最近的触摸，并假设移动的是同一个手指。

Answer 2

使用传递到touchesBegan:方法中的touches NSSet，而不是来自事件的allTouches:。