实现类似系统自带的提示框覆盖的效果

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    

    UIButton * bt = [UIButton buttonWithType:UIButtonTypeContactAdd];

    bt.frame = CGRectMake(100, 100, 100, 100);

    [self.view addSubview:bt];

    [bt addTarget:self action:@selector(btTTTClic:) forControlEvents:UIControlEventTouchUpInside];

}

- (void)btTTTClic:(UIButton * )bt

{

    UIView * view = [[UIView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];

    view.tag = 200;

    view.backgroundColor = [UIColor grayColor];

    view.alpha = 0.8;

    

    [[UIApplication sharedApplication].delegate.window.rootViewController.view addSubview:view];

    

    UIButton * btt = [UIButton buttonWithType:UIButtonTypeContactAdd];

    btt.frame = CGRectMake(100, 100, 100, 100);

    [view addSubview:btt];

    [btt addTarget:self action:@selector(btTTTCli:) forControlEvents:UIControlEventTouchUpInside];

    

}

- (void)btTTTCli:(UIButton *)bt

{

    UIView * view = [[UIApplication sharedApplication].delegate.window.rootViewController.view viewWithTag:200];

[UIView animateWithDuration:0.2 animations:^{

    [view setFrame:CGRectMake(0, [UIScreen mainScreen].bounds.size.height, [UIScreen mainScreen].bounds.size.width, 0)];

} completion:^(BOOL finished) {

    [view removeFromSuperview];

}];

}

核心代码 其实就一句：[[UIApplication sharedApplication].delegate.window.rootViewController.viewaddSubview:view];

和大家分享一下，同时请教大家一个问题 我敲代码的时候 部分代码不知道为什么没有提示 希望大家能留言帮忙解决一下！