iOS use the volume buttons as input
ios5, iphone
Solution
See the Audio Session Services References for more details, but basically you start an audio session with `AudioSessionInitialize`. Then you make it active with `AudioSessionSetActive`. Then listen for changes in the volume with `AudioSessionAddPropertyListener` where you can pass a callback that has type `AudioSessionPropertyListener`.
Check the following website out for an example: http://fredandrandall.com/blog/2011/11/18/taking-control-of-the-volume-buttons-on-ios-like-camera/
Problem
I've recently downloaded an app that uses the 'Volume -' button to toggle a value, and it uses the 'Volume +' button to start/stop recording of video. The app is called SloPro, and can be found in the app store. I thought it wasn't allowed to modify the behaviour of the iPhone's hardware. Any ideas on how this is done?