检测外部触摸拖动结束

Question

我在按钮上有一个 Touch Drag Outside 事件，我想在用户停止拖动并再次抬起屏幕手指时检测并运行一个方法。我在按钮中找不到与该事件匹配的事件，并且 touchesEnded 也不起作用。 怎么可能？

Answer 1

你应该选择touchesCancelled:withEvent:

Answer 2

You can use "PangestureRecognizer" in this case and can determine the states of gestures

if (gestureRecognizer.state == UIGestureRecognizerStateBegan) 
{

//do something

}

else if (gestureRecognizer.state == UIGestureRecognizerStateChanged) 
{

//do something

}
else if (gestureRecognizer.state == UIGestureRecognizerStateEnded)
{

//do something

}