Detecting inputs and outputs after app moves to background

Question

I'm trying to detect when headphones are plugged into the iPhone. I do this buy the following approach.

//Init the AVAudioSession
-(void)viewDidLoad
{
    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionMixWithOthers error:&error];    
    NSError *activationError = nil;

    [[AVAudioSession sharedInstance] setActive: YES error: &activationError];
}

//Get the current audio session route
-(void)viewWillAppear
{
    AVAudioSessionRouteDescription  *route = [[AVAudioSession sharedInstance] currentRoute];
}

This works fine and the route.inputs and route.outputs will contain the headphones and the microphone for a wired iPhone headset and will show the built in receiver and built in microphone when the headphones are unplugged. The problem I'm running into is when I press the home button on my app and it moves to the background. When I bring the app back into the foreground the route.inputs is always empty. My question is: Do I need to set the [[AVAudioSession sharedInstance] setActive:NO error: &activiationError] in my appDelegate when applicaionWillResign active is called? Because when route.inputs comes back empty, the headphones are still plugged in and should be detected. Any help would be appreciated. Thank you.

score 1 · Answer 1 · edited May 23 '17 at 10:28

I think a better approach is this :

- (BOOL)isHeadsetPluggedIn 
{
    AVAudioSessionRouteDescription* route = [[AVAudioSession sharedInstance] currentRoute];
    for (AVAudioSessionPortDescription* desc in [route outputs]) 
    {
        if ([[desc portType] isEqualToString:AVAudioSessionPortHeadphones])
            return YES;
    }
    return NO;
}

I just tested this and this works even when coming back to foreground from background, and also on viewDiDLoad

Link to Original Answer

Detecting inputs and outputs after app moves to background

1 Answers1