Handle UILocalNotification in UIViewController using NSNotification after the app has been terminated - ios

Question

I'm working with UILocalNotification and I would like to notify one of my controller that the notification has been received even if the app has been terminated.
In my appDelegate I implemented this function:
-(void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification
{
if ([application applicationState] == UIApplicationStateInactive) {
[[NSNotificationCenter defaultCenter] postNotificationName:#"localNotificationReceived" object:notification.userInfo];
}
}
In my UIViewController I implemented the observer on the viewDidLoad method
- (void)viewDidLoad
{
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(didlocalNotificationReceived:) name:#"localNotificationReceived" object:nil];
}
It works perfectly when the app run in background. Since the viewDidLoad method has already been called and the Observer is waiting..
The issue is when I kill the app. Then the observer of my controller is gone and the didlocalNotificationReceived method is never called.
I think that it's because when I receive the localNotification and run the app again. The didReceiveLocalNotification: method is called before the viewDidLoad of my UIViewController. Then the observer is created after the PostNotificationName then the observer receives nothing.
I would like to know if there is some best practices or pattern to handle this kind of issue.
I know that the didFinishLaunchingWithOptions method is called before didlocalNotificationReceived so there is probably something to do there.
UPDATE :
I also discovered that when is app is terminated. Once you tap the notification, It opens the app, call the function didFinishLaunchingWithOptions but never call didReceiveLocalNotification. So I think that I'm gonna handle both cases differently.

Answer 1

Ok I found the answer.
I actually, initialize manually my storyboard, and be cautious that I initialize my main view before posting the NSNotification
My didFinishLaunchingWithOptions: method in my appDelegate looks like that:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"Main" bundle:[NSBundle mainBundle]];
UIViewController *vc =[storyboard instantiateInitialViewController]; //call the initWithCoder: method of my controller
if (launchOptions[UIApplicationLaunchOptionsLocalNotificationKey]) {
UILocalNotification *localNotification = launchOptions[UIApplicationLaunchOptionsLocalNotificationKey];
[[NSNotificationCenter defaultCenter] postNotificationName:#"localNotificationReceived" object:localNotification.userInfo];
}
self.window.rootViewController = vc;
[self.window makeKeyAndVisible];
return YES;
}
Then in my UIViewController I create the NSNotification observer in the initWithCoder: method instead of in viewDidLoad:
- (instancetype)initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
if (self) {
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(didlocalNotificationReceived:) name:#"localNotificationReceived" object:nil];
}
return self;
}
- (void)didlocalNotificationReceived:(NSNotification *)notification
{
//Execute whatever method when received local notification
}
And when the app is not killed I still use the didReceiveLocalNotification: method:
-(void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification
{
if ([application applicationState] == UIApplicationStateInactive) {
[[NSNotificationCenter defaultCenter] postNotificationName:#"localNotificationReceived" object:notification.userInfo];
}
}
I'm not sure if it's the best practice. But it works well !
Hope it'll help :)