有没有办法让App Delegate在条件条件下运行，然后选择情节提要入口点？

Question

如果我使用情节提要，而入口点是供viewController1使用的。

有没有一种方法可以让App Delegate运行条件并选择情节提要入口点-viewController1或viewController2？

我想从App Delegate中选择是否打开位置服务，然后执行以下操作：

   (![CLLocationManager locationServicesEnabled]) 
   {

        self.viewController = [[viewController1 alloc] init];

        NSLog(@"vc is viewController2 from app del. loc svcs off");

    }
    else if ([CLLocationManager locationServicesEnabled])  
    {
        // alert location services denied

        self.viewController = [[viewController2 alloc] init];

        NSLog(@"vc is viewController2 from app del. loc svcs on");

        NSLog(@"core location is on");

    }

Answer 1

是的，你可以这么做。

用以下方法写下您的条件：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

做这样的事情

if(Con1)
{
   window.rootViewController = [window.rootViewController.storyboard instantiateViewControllerWithIdentifier:@"rootViewController1"];
}
else
{
    window.rootViewController = [window.rootViewController.storyboard instantiateViewControllerWithIdentifier:@"rootViewController2"];
}

Answer 2

您可以将VC1设置为初始视图控制器（通常），如果您想将VC2呈现为初始控制器，请在appDelegate中执行以下操作：

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
[self.window setRootViewController:[storyboard instantiateViewControllerWithIdentifier:@"VC2"]];
[self.window makeKeyAndVisible];

如果您未明确执行makeKeyAndVisible，iOS将使用情节提要中的初始视图控制器自动进行操作

Answer 3

    NSString *identifier;

    (![CLLocationManager locationServicesEnabled]) {

          identifier = @"UNIQUE_ID_OF_VIEW_CONTROLLER1";
    }

    else if ([CLLocationManager locationServicesEnabled])

    {
          identifier = @"UNIQUE_ID_OF_VIEW_CONTROLLER2";

    }   

    UIViewController *firstView = [storyboard instantiateViewControllerWithIdentifier:identifier];

    // NOW SET IT ROOT VIEW CONTROLLER OF THE APP 
    [self.window setRootViewController:firstView];

    [self.window makeKeyAndVisible];

    return YES;