Question

I have a Tab bar app with 3 view controller, the FirstViewController have an audio player with the list of song and play/pause button.
Now I want for SecondviewController and ThirdViewController to add a button who will call the method – (void) playpause of the FirstViewController class.

Looks easy but I didn´t find the way to make it working, i tried that :

  - (IBAction) playpause1
 {
PlayerAppDelegate *appDelegate = (PlayerAppDelegate*)[[UIApplication sharedApplication] delegate];
[appDelegate performSelector:@selector(playpause)];
NSLog(@"playpause test");   

}

But this code only control the method in app delegate, not directly on the FirstViewController class like I need.

Any tips ?

Answer 1

There are a number of possibilities:

• Move the audio playing capability to a separate object, since it’s a distinct task from what a view controller normally does. Then give all three view controllers a reference to that audio player and let them use it as necessary.

• Have the object that creates the view controllers (typically the app delegate) give the second and third view controllers each a reference to the first view controller and let them send the -playpause message.

• Use notifications. The second and third view controllers can simply post a notification that the first controller will listen for. This avoids the need to have the three view controllers know about each other.