objective c - Detect iPhone Volume Button Up Press?

Question

Is there a notification that I can listen to that will tell me when an iPhone's volume is turned up?

I know about the AVSystemController_SystemVolumeDidChangeNotification, but it is essential that the notification only be triggered when the volume has been turned up, not up or down.

Secondly, how can I hide the translucent view that appears when the volume up button is pressed, showing the system's volume? Camera+ has implemented this.

Answer 1

If you want an event you can register a listener on the "outputVolume" property:

- (void)viewWillAppear:(BOOL)animated {

    AVAudioSession* audioSession = [AVAudioSession sharedInstance];

    [audioSession setActive:YES error:nil];
    [audioSession addObserver:self
                    forKeyPath:@"outputVolume"
                       options:0
                       context:nil];
}

-(void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

    if ([keyPath isEqual:@"outputVolume"]) {
        NSLog(@"volume changed!");
    }
}