检测 UIView 是否在父级中的另一个 UIView 后面 [英] Detect if a UIView is behind another UIView in parent

问题描述

我有一个带有多个子视图的父 UIView.

I have a parent UIView with several subviews.

子视图是兄弟视图 - 子视图不是彼此的子视图.(每个在他们的超视图中处于相同的层级)

The subviews are siblings - the child-views are not sub views of each other. (Each at the same heirarchical level in their superview)

例如:

UIView *containerView = [[UIView alloc] initWithFrame:frame];
CustomUIView *childView = [[UIView alloc] initWithFrame:anotherFrame];
CustomUIView *yetAnotherChildView = [[UIView alloc] initWithFrame:anotherFrame];

[containerView addSubview:childView];
[containerView addSubview:yetAnotherChildView];

[containerView bringSubviewToFront:childView];

我希望 yetAnotherChildView 能够检测到它已移回视图层次结构中.这怎么办?

I want yetAnotherChildView to be able to detect it was moved back in the view heirarchy. How can this be done?

编辑:

我知道 containerView 可以知道什么子视图在什么之上 - 但我不想(不能)containerView 通知它的子视图他们的订单已更改 - 想象一下在股票视图之上添加一个子视图 - 股票视图不知道其子视图并且他们希望收到此类通知.

I understand that the containerView can know what subviews are above what - but I don't wan't (can't) the containerView notify its subviews that their order changed - Imagine adding a subview ontop of a stock view - the stock view has no idea of its subviews and that they would like to receive such a notification.

子视图 CustomUIView 需要观察其 superview

The subview CustomUIView would need to observe some change in its superview

例如(这可能是一个非常糟糕的解决方案)

for instance (this probably is a very bad solution)

CustomUIView

-(id)initWithFrame
{
  [self.superView addObserver:self forKeyPath:@"subViews" options:options context:context];
}

- (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(id)object
                        change:(NSDictionary *)change
                       context:(void *)context
{
 // if keyPath is "subViews" array check if "this" view is ontop and adjust self accordingly
}

推荐答案

试试这个，它会给你给定视图后面的所有视图

Try this it will give you all views behind given view

-(NSMutableArray *)getAllViewsBehindView:(UIView *)view{
NSMutableArray *tempArr = [NSMutableArray array];

NSArray *subViews = view.superview.subviews;

for (int i = 0; (i < subViews.count); i++)
{
    UIView *viewT = [subViews objectAtIndex:i];

    if (viewT == view)
    {
        return tempArr;
    }
    else
    {
        if (CGRectIntersectsRect(viewT.frame, view.frame))
        {
            [tempArr addObject:viewT];
        }
    }

}

return tempArr;}

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