如何从AppDelegate打开特定的ViewController？

Question

I know this question has been asked many times. But I am a newbie and I was not able to find any solutions to help me in my condition. Here is a brief explanation:

I have an app with a UITabBarController as root.

Inside the app delegate I check if user is already logged in. If yes I will open root controller.

self.window.rootViewController = [[UIStoryboard storyboardWithName:@"Main" bundle:[NSBundle mainBundle]] instantiateInitialViewController];

My application is working fine. But now I need to implement notification. When I get notification content inside didFinishLaunchingWithOptions :

NSDictionary *notificationPayload = launchOptions[UIApplicationLaunchOptionsRemoteNotificationKey];
NSString *messageType = [notificationPayload objectForKey:@"messageType"];

Now if there is a message:

if (messageType.length > 0 )
{
    //Here based on message I need to open different tabs of TabBarViewController

     UITabBarController *tabBarController = (UITabBarController *)self.window.rootViewController;
     //RootTabBarViewController *listingVC = [[RootTabBarViewController alloc] init];
     [(UINavigationController *)self.window.rootViewController pushViewController:tabBarController animated:YES];

}

This piece of code above did not work for me. And also I don't know how to open different tabs and give value to their badges form here. It always navigate to the first index tab with these code. I have seen other answers say:

self.tabBarController.selectedIndex = 2;

But did not work for me. I have implemented an UITabBarController class and I can set value for the each tab item badges from there but I get my notificationPayLoad in AppDelegate.

Answer 1

As you told that you are using TabBarController with storyboard. Then why are you initialising again? You can just do as following

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    if([[NSUserDefaults standardUserDefaults]boolForKey:@"Selected"])
    {
        [[NSUserDefaults standardUserDefaults]setBool:NO forKey:@"Selected"];
        UITabBarController *tabController = (UITabBarController*)self.window.rootViewController;
        tabController.selectedIndex=1;
    }else{
        [[NSUserDefaults standardUserDefaults]setBool:YES forKey:@"Selected"];
        UITabBarController *tabController = (UITabBarController*)self.window.rootViewController;
        tabController.selectedIndex=0;
    }
    return YES;
}

Here I am just showing a demo code for accessing TabbarController at different selectedIndex within didFinishLaunching.

Answer 2

Assuming that you have designed(drag n dropped UITabBar/ UITabBarController) in storyboard.

if (messageType.length > 0 )
{
    //Here based on message I need to open different tabs of TabBarViewController



    NSUInteger indexOfRequiredTab = 2;// pass the index of controller here

    id rootObject = self.window.rootViewController;
    if ([rootObject isKindOfClass:[UITabBarController class]]) {

        UITabBarController *tabBarControllerObject = (UITabBarController *)rootObject;

        if (indexOfRequiredTab != NSNotFound && indexOfRequiredTab < tabBarControllerObject.tabBar.items.count) {

            tabBarControllerObject.tabBar.items[indexOfRequiredTab].badgeValue = @"2"; //to set badge value

            tabBarControllerObject.selectedIndex = indexOfRequiredTab; //Setting this property changes the selected view controller to the one at the given index in the viewControllers array
        }
    }


}

Views designed on story board are already initialized, we can access them using the IBOutlet and change their properties.