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我有一个简单的应用程序，可以打印所有触摸事件的坐标。在模拟器中效果很好。

在我的设备 (iPhone) 上，它最多可以使用两个手指。当我用三个手指快速点击时，事件touchesCancelled被触发。

有人可以向我解释一下吗？这是位于我的 UIView 中的打印代码（以防出现问题）。

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInView:touch.view];
        NSLog(@"Began  %f %f",  location.x, location.y);
    }
}


-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{  
    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInView:touch.view];
        NSLog(@"Moved  %f %f",  location.x, location.y);
    }
}


-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInView:touch.view];
        NSLog(@"Ended  %f %f",  location.x, location.y);
    }
}

-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"Phase: Touches cancelled");

    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInView:touch.view];
        NSLog(@"Cancelled  %f %f",  location.x, location.y);

    }
}

序列的一个例子是这个：

Began  38.000000 263.000000
Began  173.500000 238.500000
Moved  41.500000 263.000000
Phase: Touches cancelled   <<<< third touch
Cancelled  41.500000 263.000000
Cancelled  173.500000 238.500000

谢谢你。

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