iOS:切换到第二个 ViewController

Question

我正在编写一个脚本，该脚本使用 Reachability 检查 Internet 连接。如果没有互联网，我希望它加载第二个 ViewController。这是我目前所拥有的:

-(BOOL) hasInternet {
    Reachability *reach = [Reachability reachabilityWithHostName:@"http://www.google.com"];
    NetworkStatus internetStatus = [reach currentReachabilityStatus];
    if( internetStatus == NotReachable){
        SecondViewController *second = [[SecondViewController alloc] initWithNibName:nil bundle:nil];
        [self presentViewController:second animated:YES completion:nil];
    }else{

    }
    return YES;
}

我得到的错误是:

Attempt to present SecondViewController: 0x7ff780628d10 on ViewController: 0x7ff780719830 whose view is not in the window hierarchy!

谁能看出我哪里错了。

非常感谢您的帮助和时间。

Answer 1

You are attempting to present another viewController while first ViewController has yet not loaded.

解决方案:

1. 在 viewDidAppear() 方法中调用您的函数。
2. 写下你想要加载的View Controllers Nib Name