使用RootviewController运行的应用程序错误 - 应用程序在应用程序启动结束时应具有根视图控制器

Question

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
}

我不知道这个方法有什么问题。我刚刚创建了一个新项目并运行它。它显示应用程序在应用程序启动结束时应该有一个根视图控制器

Answer 1

如果您有MainWindow.xib。

删除以下行。不要删除MainWindow.xib

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

---

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

OR

不要删除上面的行。删除MainWindow.xib和项目摘要主界面设置为null。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
}