ios - UIView拖拽-addsubview时拖动view消失 : is called?

Question

我在 UIView 容器中有 DragView 对象和 DropView 对象，它们都是 UIView 子类.以下 selector 方法在手势平移时被调用。问题是当我将 DragView 对象拖到 DropView 对象上时，DragView 对象消失了。我不知道我做错了什么。

 - (void)dragViewMoved:(UIPanGestureRecognizer *)gesture{

    CGPoint touchLocation = [gesture locationInView:self];

    static DragView *currentDragView;
    static DropView *currentDropView;

   if(UIGestureRecognizerStateBegan == gesture.state){

        for(DragView *dragView in self.dragViews){

            if(CGRectContainsPoint(dragView.frame, touchLocation)){
                currentDragView = dragView;
                break;
            }
        }

    }else if(UIGestureRecognizerStateChanged == gesture.state){

        currentDragView.center = touchLocation;

        for(DropView *dropView in self.dropViews){

            if(CGRectIntersectsRect(currentDragView.frame, dropView.frame))
                currentDropView = dropView;

        }

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

        if(CGRectIntersectsRect(currentDragView.frame, currentDropView.frame)){

            //I think the problem is happening here
            currentDragView.center = touchLocation;
            [currentDragView removeFromSuperview];
            [currentDropView addSubview:currentDragView];

        }

        currentDragView = nil;

    }

}

Answer 1

而不是这样做:

currentDragView.center = touchLocation;

试着改成这样:

currentDragView.center = [gesture translationInView:currentDropView];

更新:

尝试切换此行:

static DragView *currentDragView;

对此:

DragView *currentDragView  = gesture.view;