iOS UIWindow*上层添加视图或者其他控件

UIView *view = [[UIView alloc]initWithFrame:CGRectMake(self.view.frame.size.width-50,20, 30, 30)];

view.backgroundColor = [UIColor whiteColor];

view.layer.masksToBounds =YES;

view.layer.cornerRadius =15;

//获取当前UIWindow 并添加一个视图

UIApplication *ap = [UIApplication sharedApplication];