Question

I have an animation in viewDidLoad that runs the first time the app is launched. if you exit the app, then launch it again the animation doesn’t play.

how would I go about making the animation play each and every time the app is opened,

thanks for any help

Answer 1

In iOS 4, pressing the home button doesn’t terminate the app, it suspends it. When the app is made active again, a UIApplicationDidBecomeActiveNotification is posted. Register for that notification and initiate the animation in your handler.

Edit: Added code below.

Here’s one way to do it: Have your view controller become an observer of UIApplicationDidBecomeActiveNotification in its viewWillAppear: method.

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(performAnimation:) name:UIApplicationDidBecomeActiveNotification object:nil];
}

Unregister for the notification in your view controller’s viewDidDisappear: method.

- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationDidBecomeActiveNotification object:nil];
}

Finally, put your animation code in the selector specified when registering to receive the notification.

- (void)performAnimation:(NSNotification *)aNotification {
    // Animation code.
}