View 不在窗口层次结构中的iOS

Question

当我从 PassCode Controller 移动到 OTP ViewController 时，我在控制台中收到以下错误:

Warning: Attempt to present < OTPController: 0x1e56e0a0 > on < PassCodeController: 0x1ec3e000> whose view is not in the window hierarchy!

这是我用来在 View 之间切换的代码:

UIStoryboard  *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    OTPViewController *lOTPViewController = [storyboard instantiateViewControllerWithIdentifier:@"OTPViewController"];
    lOTPViewController.comingFromReg = true;

    [self presentViewController:lOTPViewController animated:YES
                     completion:nil];

我正在展示来自 RegistrationViewController 的 PassCode Controller :

UIStoryboard* storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
        PassCodeViewController *passVC =  [storyboard instantiateViewControllerWithIdentifier:@"PassCodeViewController"];
        [self presentViewController:passVC animated:YES completion:nil];

Answer 1

发生这种情况是因为两个 View Controller 同时存在和关闭，或者您试图在 View Controller 打开 ViewDidload 方法时立即呈现 ViewController

首先:

• 从 viewDidAppear 方法或代替 ViewDidload 呈现 ViewController。

第二:

我建议使用完成方法来呈现和关闭 viewcontrolelr，如下例所示:

[self presentViewController:lOTPViewController animated:YES
                             completion:^{

        }];

更新:

创建一个单独的方法来呈现 OTPViewController，如下所示:

-(void)PresentOTPViewController
{

    UIStoryboard  *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    OTPViewController *lOTPViewController = [storyboard instantiateViewControllerWithIdentifier:@"OTPViewController"];
    lOTPViewController.comingFromReg = true;

    [self presentViewController:lOTPViewController animated:YES
                     completion:^{}];

}

现在使用 performSelector 以 1 秒 Delaya 调用此方法

[self performSelector:@selector(PresentOTPViewController) withObject:self afterDelay:1.0 ];

你需要把上面的performselect代码放在

[self dismissViewControllerAnimated:YES completion:^{
 [self performSelector:@selector(PresentOTPViewController) withObject:self afterDelay:1.0 ];
}]; // this is the dismiss method of PassCodeViewController