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

There is no documented way to to this, but you can use this workaround. Register for AVSystemController_SystemVolumeDidChangeNotification notification and add an MPVolumeView which will prevent the system volume view from showing up.

MPVolumeView *volumeView = [[MPVolumeView alloc] initWithFrame:CGRectMake(-100, 0, 10, 0)];
[volumeView sizeToFit];
[self.view addSubview:volumeView];

And don’t forget to start an Audio Session

AudioSessionInitialize(NULL, NULL, NULL, NULL);
AudioSessionSetActive(true);

In This case, the MPVolumeView is hidden from the user.

As for checking if volume up or down was pressed, just grab the current application’s volume

float volumeLevel = [[MPMusicPlayerController applicationMusicPlayer] volume];  

and compare it with new volume after the button was pressed in notification callback

If you don’t want to do it by yourself, there’s a drop-in class available in github

https://github.com/blladnar/RBVolumeButtons