ios - Root View Controller 偶尔丢失

Question

有时，我的应用启动时出现黑屏，并出现以下警告:

Application windows are expected to have a root view controller at the end of application launch

我使用 Storyboard。当我编译应用程序时，这往往会不时随机发生，并且只有在我更改代码和/或 Storyboard然后重新编译时，错误才会消失。 错误的编译将继续以错误的状态启动应用程序，即使您重新启动它也是如此。

应用程序本身(对我来说)唯一不寻常的地方是它的初始 View 包含一个 map View ，上面有多个容器 View (在启动时隐藏)。

我试过使用 Spark Inspector发生这种情况时调试 View 层次结构，它表明唯一的元素是 UIWindow，根本没有加载任何 UIView。

这是我的 didFinishLaunchingWithOptions(这是应用程序委托(delegate)中唯一包含代码的方法)，如 Matt 所要求的:

- (BOOL)application:(UIApplication *)application
    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [DDLog addLogger:[DDASLLogger sharedInstance]];
    [DDLog addLogger:[DDTTYLogger sharedInstance]];
    [[DDTTYLogger sharedInstance] setColorsEnabled:YES];
    UIColor *pink = [UIColor colorWithRed:(118 / 255.0)
                                    green:(214 / 255.0)
                                     blue:(84 / 255.0)
                                    alpha:1.0];
    [[DDTTYLogger sharedInstance] setForegroundColor:pink
                                     backgroundColor:nil
                                             forFlag:LOG_FLAG_INFO];

    #ifdef DEBUG
        DDLogInfo(@"Launching in debug mode");
    #else
        DDLogWarn(@"Launching in release mode");
    #endif

    [AFNetworkActivityIndicatorManager sharedManager].enabled = YES;
    [[AFNetworkActivityLogger sharedLogger] startLogging];

    [[UITextField appearanceWhenContainedIn:[UISearchBar class], nil]
        setFont:[UIFont fontWithName:@"OpenSans" size:14]];

    NSMutableDictionary *titleBarAttributes = [NSMutableDictionary
        dictionaryWithDictionary:
            [[UINavigationBar appearance] titleTextAttributes]];
    [titleBarAttributes setValue:[UIFont fontWithName:@"OpenSans" size:18]
                          forKey:NSFontAttributeName];
    [[UINavigationBar appearance] setTitleTextAttributes:titleBarAttributes];

    return YES;
}

Answer 1

如果你正在使用 Storyboard，你可以从 Storyboard设置 Root View Controller

否则您必须在 AppDelegate 中以编程方式创建它

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    UINavigationController *rootViewController = [[UINavigationController alloc] initWithNibName:@"RootVC" bundle:nil];
    self.window.rootViewController = rootViewController;
    [self.window makeKeyAndVisible];
    return YES;
}