有沒有辦法讓App Delegate在條件條件下運行，然后選擇情節提要入口點？

Question

如果我使用情節提要，而入口點是供viewController1使用的。

有沒有一種方法可以讓App Delegate運行條件並選擇情節提要入口點-viewController1或viewController2？

我想從App Delegate中選擇是否打開位置服務，然后執行以下操作：

   (![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，你可以這么做。

用以下方法寫下您的條件：

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

做這樣的事情

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

Answer 2

您可以將VC1設置為初始視圖控制器（通常），如果您想將VC2呈現為初始控制器，請在appDelegate中執行以下操作：

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

如果您未明確執行makeKeyAndVisible，iOS將使用情節提要中的初始視圖控制器自動進行操作

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;