AppDelegate *delegate = (AppDelegate *)[UIApplication sharedApplication].delegate;
 UIWindow *window = delegate.window;
 UIView *aView = [[UIView alloc]initWithFrame:CGRectMake(0,100,100)];
 aView.backgroundColor = [UIColor blackColor];
 [window addSubview:aView];

这段代码不起作用.我想克隆UIAlertView的属性.当我们打电话时,它会弹出一切
[alertViewInstance show];方法.

试过这个：

UIView *aView = [[UIView alloc]initWithFrame:CGRectMake(0,100)];
    UIWindow* window = [UIApplication sharedApplication].keyWindow;

    if (!window) {
        window = [[UIApplication sharedApplication].windows objectAtIndex:0];
    }

    [window addSubview:aView];
    [window bringSubviewToFront:aView];