Xcode 11版本纯代码设置window.rootviewController

更新了Xcode11 以后选择OC语言创建新工程的时候,可以发现工程里多了两个delegate文件:SceneDelegate.h/SceneDelegate.m.对于已经习惯用纯代码的朋友,如果还用以往的方式,在AppDelegate.m里面设置window.rootViewController,就会发现程序会报错了.下面直接说两种解决方案:

方案1:

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- (void)scene:(UIScene *)scene willConnectToSession:(UISceneSession *)session options:(UISceneConnectionOptions *)connectionOptions {
    
    if ([scene isKindOfClass:[UIWindowScene class]]) {
        UIWindowScene *windowScene = (UIWindowScene *)scene;
        UIWindow *window = [[UIWindow alloc] initWithWindowScene:windowScene];
        UIViewController *vc = [[UIViewController alloc] init];
        vc.view.backgroundColor = [UIColor redColor];
        window.rootViewController = vc;
        self.window = window;
        window.backgroundColor = [UIColor whiteColor];
        [window makeKeyAndVisible];
    }
}

方案2:

把info.plist 文件中的 Application Scene Manifest 这一项直接删除,
然后在AppDelegate.h中添加一个属性:window,Xcode11把这个属性删除了需要我们手动添加回来;然后还要删除AppDelegate.m中的两个方法:

//- (UISceneConfiguration *)application:(UIApplication *)application configurationForConnectingSceneSession:(UISceneSession *)connectingSceneSession options:(UISceneConnectionOptions *)options {
//    // Called when a new scene session is being created.
//    // Use this method to select a configuration to create the new scene with.
//    return [[UISceneConfiguration alloc] initWithName:@"Default Configuration" sessionRole:connectingSceneSession.role];
//}


//- (void)application:(UIApplication *)application didDiscardSceneSessions:(NSSet<UISceneSession *> *)sceneSessions {
//    // Called when the user discards a scene session.
//    // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
//    // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
//}

做完上面这些动作,就可以按照XCode11以前的方式,在AppDelegate.h中设置window.rootviewcontroller了.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    
    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    UIViewController *v1 = [UIViewController new];
    UINavigationController *nvc = [[UINavigationController alloc] initWithRootViewController:v1];
    v1.view.backgroundColor = [UIColor redColor];
    self.window.rootViewController = nvc;
    [self.window makeKeyAndVisible];
    return YES;
}