How to implement a volume key shutter for iPhone?

Question

I want to implement the same behavior with the native camera of iOS5:

• press the volume + button to take a photo

What\'s the

Answer 1

I call this method from viewDidAppear

-(void) startTrackingVolume
{
    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryAmbient withOptions:AVAudioSessionCategoryOptionMixWithOthers error:nil];
    [[AVAudioSession sharedInstance] setActive:YES error:nil];

    if (!self.volumeView) {
        // put it somewhere outside the bounds of parent view
        self.volumeView = [[MPVolumeView alloc] initWithFrame:CGRectMake(-100, -100, 10, 0)];
        [self.volumeView sizeToFit];
    }

    if (!self.volumeView.superview) {
        [self.view addSubview:self.volumeView];
    }
}

In viewWillDisappear in call

[[AVAudioSession sharedInstance] setActive:NO error:nil];