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?
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I was under the impression that apps like that shouldn't make it into the app store. I wouldn't be surprised if Apple removes the app if they find out what is going on. – Sergey Kalinichenko May 05 '12 at 03:05
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I'd be surprised if they didn't know. The first time you run the app, a message pops up saying this can be done... – David Skrundz May 05 '12 at 03:05
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I've added this question to favorites - I'm very curious to see an answer. – Sergey Kalinichenko May 05 '12 at 03:08
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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/
Espresso
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I think this is only acceptable in camera apps where it's judiciously used. – Espresso May 05 '12 at 03:32
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should check the answer here http://stackoverflow.com/questions/28193626/cleanest-way-of-capturing-volume-up-down-button-press-on-ios-8 basically you can use https://github.com/jpsim/JPSVolumeButtonHandler – Pnar Sbi Wer Sep 17 '15 at 05:56