handling appDelegate in my app - objective-c

Question

I am new to iOS app development and near completion to developing my first app. So now begins the finishing work, which includes how my app should behave when it reaches certain events or states. I know the code to handle such tasks goes into appDelegate.m but I am kinda confused about what I am actually supposed to do. My app is simple, it triggers an animation with sound when a button is pressed and I want the sound to stop as soon as the user hits the home button. I tried this but in vain:
- (void)applicationDidEnterBackground:(UIApplication *)application
{
finalViewController.AudioServicesDisposeSystemSoundID(soundID)
}
Besides my app also crashes when I press the home button sign twice and try to close my app. It gives me the 'signal SIGABRT' error in main.m. Please help.

Answer 1

Try doing it in here instead:
- (void)applicationWillResignActive:(UIApplication *)application{}
or maybe
- (void)applicationWillTerminate:(UIApplication *)application{}

Answer 2

You say that you're getting an error like:
use of undeclared identifier soundID
If soundID is a property of your app delegate, you should access it using property notation, like:
self.soundID
or:
[self soundID]
The "undeclared identifier" means that the compiler doesn't know what you're talking about when you say soundID. The instance variable that's backing that property probably has a different name (like _soundID), so soundID doesn't refer to the ivar itself, it's just the property name.

Answer 3

Use the given code snippet to stop the sound & access the soundId which you have passed in AudioServicesPlaySystemSound(soundID). You can create the soundId variable in appDelegate & save the soundId when you play the system sound.
- (void)applicationDidEnterBackground:(UIApplication *)application
{
AudioServicesDisposeSystemSoundID(soundID)
}