I started with the code given above by jpsetung, but there were a few issues with it for my use case:
- No evidence of something called
kAudioSessionProperty_AudioRoute
in the docs
- Leaks
route
- No audio session check
- String check for headphones instead of logical awareness of categories
- I was more interested in whether the iPhone was using its speakers, with "headphones" meaning "anything other than speakers". I feel that leaving out options like "bluetooth", "airplay", or "lineout" was dangerous.
This implementation broadens the check to allow for any type of specified output:
BOOL isAudioRouteAvailable(CFStringRef routeType)
{
/*
As of iOS 5:
kAudioSessionOutputRoute_LineOut;
kAudioSessionOutputRoute_Headphones;
kAudioSessionOutputRoute_BluetoothHFP;
kAudioSessionOutputRoute_BluetoothA2DP;
kAudioSessionOutputRoute_BuiltInReceiver;
kAudioSessionOutputRoute_BuiltInSpeaker;
kAudioSessionOutputRoute_USBAudio;
kAudioSessionOutputRoute_HDMI;
kAudioSessionOutputRoute_AirPlay;
*/
//Prep
BOOL foundRoute = NO;
CFDictionaryRef description = NULL;
//Session
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
AudioSessionInitialize(NULL, NULL, NULL, NULL);
});
//Property
UInt32 propertySize;
AudioSessionGetPropertySize(kAudioSessionProperty_AudioRouteDescription, &propertySize);
OSStatus error = AudioSessionGetProperty(kAudioSessionProperty_AudioRouteDescription, &propertySize, &description);
if ( !error && description ) {
CFArrayRef outputs = CFDictionaryGetValue(description, kAudioSession_AudioRouteKey_Outputs);
CFIndex count = CFArrayGetCount(outputs);
if ( outputs && count ) {
for (CFIndex i = 0; i < count; i++) {
CFDictionaryRef route = CFArrayGetValueAtIndex(outputs, i);
CFStringRef type = CFDictionaryGetValue(route, kAudioSession_AudioRouteKey_Type);
NSLog(@"Got audio route %@", type);
//Audio route type
if ( CFStringCompare(type, routeType, 0) == kCFCompareEqualTo ) {
foundRoute = YES;
break;
}
}
}
} else if ( error ) {
NSLog(@"Audio route error %ld", error);
}
//Cleanup
if ( description ) {
CFRelease(description);
}
//Done
return foundRoute;
}
Used like so:
if ( isAudioRouteAvailable(kAudioSessionOutputRoute_BuiltInSpeaker) ) {
//Do great things...
}