在UIViews之间拖动UIView

Question

我有一个包含在UIView对象A中的UIView对象.我希望能够触摸X并将其从对象A中移除并将其移动到对象B(另一个UIView)中.对象A和B都在同一个超级UIView中.

  A        B
_____    _____
|   |    |   |
| X | -> |   |
|___|    |___|

这就是我到目前为止所拥有的.

@implementation X_UIView

float deltaX;
float deltaY;

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self.superview.superview addSubview:self]; //pop dragged view outside of container view

    CGPoint beginCenter = self.center;

    UITouch * touch = [touches anyObject];
    CGPoint touchPoint = [touch locationInView:self.superview];

    deltaX = touchPoint.x - beginCenter.x;
    deltaY = touchPoint.y - beginCenter.y;
}

- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
    UITouch * touch = [touches anyObject];
    CGPoint touchPoint = [touch locationInView:self.superview];

    // Set the correct center when touched 
    touchPoint.x -= deltaX;
    touchPoint.y -= deltaY;

    self.center = touchPoint;
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    //discover view that event ended was over and add self as a subview.
}

@end

Answer 1

调用[[touches anyObject] locationInView: self.superview]在容器视图中获取手指下的点.然后发送self.superview -hitTest:withEvent:以找出X在里面的视图.请注意,它将始终返回X,因此您必须覆盖其中一个-pointIsInside:withEvent:或-hitTest:withEvent:在拖动时返回nil.这种kludge是我在容器视图中实现这种跟踪的原因,而不是在拖动视图中.