如何在所有视图的顶部添加UIView？

问题描述：

我有这样的代码：

@interface Alert : UIView 
{

}
/*
- (void) initWithTitle:(NSString*)title message:(NSString*)message cancelButtonTitle:(NSString*)cancelButtonTitle otherButtonTitles:(NSString*)buttonTitle,... delegate:(id)delegate;
*/
@end


@implementation Alert

- (void) drawRect:(CGRect)rect 
{
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextClearRect(context, rect); // Очистим context

    CGContextSetRGBFillColor(context, 255, 0, 0, 1);
    CGContextFillRect(context, CGRectMake(20, 20, 100, 100));
}

- (void) show
{
    self.center = [[[UIApplication sharedApplication] keyWindow] center];
    [[[UIApplication sharedApplication] keyWindow] addSubview:self];
    [[[UIApplication sharedApplication] keyWindow] bringSubviewToFront:self];
}

然后我就这样使用它：

- (void)viewDidLoad
{
    [super viewDidLoad];
     Alert * alert = [[Alert alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
    [alert show];
    [alert release];
}

但它不起作用（我希望看到Alert高于所有其他视图）。你能帮助我吗？

But it doesn't work(I want to see Alert above all other views). Could you help me?

答

正确处理设备方向的推荐解决方案

pod
AGWindowView 它将自动处理任何轮换和帧更改，因此您不必担心。

阅读并按照官方帖子 https://developer.apple.com/library/content/qa/qa1688/_index.html

将您的视图添加到第一个子视图，而不是将其添加到窗口

pod AGWindowView It will automatically deal with any rotation and framechanges so you won't have to worry about that.
read and follow the official post https://developer.apple.com/library/content/qa/qa1688/_index.html
Add your view to the first subview, instead of adding it to the window

UIWindow* window = [UIApplication sharedApplication].keyWindow;
if (!window) 
    window = [[UIApplication sharedApplication].windows objectAtIndex:0];
[[[window subviews] objectAtIndex:0] addSubview:myView];

您也可以将其添加到窗口中。 但它不会处理设备方向。

You can also add it to the window. It will not handle device orientation, though.

let window = UIApplication.sharedApplication().keyWindow!
let view = UIView(frame: CGRect(x: window.frame.origin.x, y: window.frame.origin.y, width: window.frame.width, height: window.frame.height))
window.addSubview(v);
view.backgroundColor = UIColor.blackColor()

如何在所有视图的顶部添加UIView？

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