ios开发新手入门-多视图控制器管理

设置根视图控制器

OC

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    //创建window 设置rootViewController ,显示出来
    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    self.window = [[TestRootViewController alloc]init]; //设置根视图控制器
    [self.window makeKeyWindow]; //设置成为主窗口并显示
    return YES;
}

swift

        let viewController = RootViewController()
        window = UIWindow.init(frame: UIScreen.main.bounds)
        window?.rootViewController = viewController

        window?.makeKeyAndVisible()