How to switch between speaker and headphones in iPhone application

Question

I've written an app that plays audio using AVAudioPlayer.

I've implemented a function that switches the audio to the speaker:

UInt32 sessionCategory = kAudioSessionCategory_MediaPlayback;
AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(sessionCategory), &sessionCategory);    
UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;
AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,sizeof (audioRouteOverride),&audioRouteOverride);

But when I try to switch it back to the Headphones using this:

UInt32 sessionCategory = kAudioSessionCategory_MediaPlayback;
AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(sessionCategory), &sessionCategory);    
UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_None;
AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,sizeof (audioRouteOverride),&audioRouteOverride); 

it remains routed through the speaker.

I cannot find any other way of directing the audio. Can anyone suggest what I'm doing wrong?

Answer 1

According to the Apple's documentation, the Audio Session route override is only availble when using the kAudioSessionCategory_PlayAndRecord category.

You can try changing the category to kAudioSessionCategory_PlayAndRecord and use the kAudioSessionProperty_OverrideCategoryDefaultToSpeaker property key to route audio to the speaker.