从xib加载iOS黑屏

Question

I am trying to load application with .xib file. I don't know why my screen turns black...

My AppDelegate code:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.

    MainViewController *mainViewController = [[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil];

    self.window.rootViewController = mainViewController;

    [self.window makeKeyAndVisible];

    return YES;
}

Answer 1

When you build your application manually (not using a storyboard), you need to create your own window.

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

When using Storyboards, the application does this whole process before calling application:didFinishLaunchingWithOptions: . That's why UIApplicationDelegate.window was added in iOS 5 and many modern tutorials don't show you the setup steps. Before then it was just common practice to have that property.