ios - 修复警告 : Attempt to present ViewController on NavigationController whose view is not in the window hierarchy

Question

目前，我已经为我的应用程序的用户设置了一个登录 View 。下面是向用户显示此登录 View 的代码:

 // Handle how we present the view
    if (self.notificationToProcess != nil) {
        [self.navigationController dismissViewControllerAnimated:YES completion:^{
            SWNotificationsViewController *viewController = [[NotificationsViewController alloc] init];
            viewController.initialDataID = self.notificationToProcess[@"Data"];
            self.notificationToProcess = nil;

            [self.navigationController pushViewController:viewController animated:YES];
        }];
    } else if (self.detailURL != nil) {
        [self.navigationController dismissViewControllerAnimated:YES completion:^{
            WebViewController *wvc = [[WebViewController alloc] init];
            wvc.URL = self.detailURL;
            wvc.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
            [self.navigationController presentViewController:wvc animated:YES completion:nil];

            self.detailURL = nil;
        }];
    } else {
        [self.navigationController dismissViewControllerAnimated:YES completion:nil];
    }

我现在尝试做的是，如果用户刚刚更新了应用程序，则首先显示 WebView 。下面是这段新代码的样子:

// Handle how we present the view.
    if (self.notificationToProcess != nil) {
        [self.navigationController dismissViewControllerAnimated:YES completion:^{
            SWNotificationsViewController *viewController = [[SWNotificationsViewController alloc] init];
            viewController.initialDataID = self.notificationToProcess[@"Data"];
            self.notificationToProcess = nil;

            [self.navigationController pushViewController:viewController animated:YES];
        }];
    } else if (self.detailURL != nil) {
        [self.navigationController dismissViewControllerAnimated:YES completion:^{
            SWWebViewController *wvc = [[SWWebViewController alloc] init];
            wvc.URL = self.detailURL;
            wvc.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
            [self.navigationController presentViewController:wvc animated:YES completion:nil];

            self.detailURL = nil;
        }];
else if (![versionOfLastRun isEqual:currentVersion])
    {
        SWWebViewController *webViewController = [[SWWebViewController alloc] init];
        NSString *url=@"http://someurl";
        webViewController.URL = url;
        webViewController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
        [self.navigationController presentViewController:webViewController animated:YES completion:nil];
        [[NSUserDefaults standardUserDefaults] setObject:currentVersion forKey:@"VersionOfLastRun"];
        [[NSUserDefaults standardUserDefaults] synchronize];

    }
    else if (versionOfLastRun == nil){
        // First start after installing the app
    }

    else {
        [self.navigationController dismissViewControllerAnimated:YES completion:nil];
    }

但是，当我运行该应用程序时，未显示 Web View ，我收到以下警告:

警告:尝试在其 View 不在窗口层次结构中的 NavigationController 上呈现 ViewController!

任何人都可以帮助我诊断问题吗？谢谢!

Answer 1

似乎您的 viewController 不在导航 Controller 层次结构中。这意味着您的 Controller 未与应处理所呈现 Controller 的导航 Controller 堆栈连接。

另一件应该有帮助的事情是设置你的 Root View Controller 如下:

self.window.rootViewController = self.ViewController;

编辑:因为您提到您不使用 Storyboard ，设置 rootViewController 应该可以解决问题。