How Do I Route Audio to Speaker without using Audi

问题:

As AudioSessionSetProperty may become deprecated, I'm trying to find an code example of how to route audio to the speaker using other means.

Previously I did the following:

-(void)setSpeakerEnabled
{
    debugLog(@"%s",__FUNCTION__);
    UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;

    AudioSessionSetProperty (
                         kAudioSessionProperty_OverrideAudioRoute,
                         sizeof (audioRouteOverride),
                         &audioRouteOverride
                         );
}

Trying to get same result but without call to AudioSessionSetProperty.

回答1:

On each release of iOS, more of the audioSession properties are migrated to AVFoundation, so you should use those in preference whenever available.

Since iOS 6 kAudioSessionProperty_OverrideAudioRoute is represented in AVAudioSession by the method

- (BOOL)overrideOutputAudioPort:error:

Available values are AVAudioSessionPortOverrideNone and AVAudioSessionPortOverrideSpeaker

Here is an example audio session configured entirely via AVFoundation:

 - (void)configureAVAudioSession
{
   // Get your app's audioSession singleton object
    AVAudioSession *session = [AVAudioSession sharedInstance];

    // Error handling
    BOOL success;
    NSError *error;

    // set the audioSession category. 
    // Needs to be Record or PlayAndRecord to use audioRouteOverride:  

    success = [session setCategory:AVAudioSessionCategoryPlayAndRecord
                             error:&error];

   if (!success) {
       NSLog(@"AVAudioSession error setting category:%@",error);
   }

    // Set the audioSession override
    success = [session overrideOutputAudioPort:AVAudioSessionPortOverrideSpeaker
                                          error:&error];
    if (!success) {
        NSLog(@"AVAudioSession error overrideOutputAudioPort:%@",error);
    }

    // Activate the audio session
    success = [session setActive:YES error:&error];
    if (!success) {
        NSLog(@"AVAudioSession error activating: %@",error);
    }
    else {
         NSLog(@"AudioSession active");
    }

}

UPDATE

Since iOS 7.0, the Audio Session Services C API is now fully deprecated in favour of AVAudioSession.

UPDATE 2

- (BOOL)overrideOutputAudioPort:error:  

is a method, not a property, and it sets an underlying write-only UInt32 value. You can't get the current value, and you should treat the method as setting a temporary state. If the audio route changes or is interrupted, the property resets to its default (AVAudioSessionPortOverrideNone). You can get interruption notifications via AVAudioSessionDelegate.

回答2:

NSError *error;
[[AVAudioSession sharedInstance] overrideOutputAudioPort:AVAudioSessionPortOverrideSpeaker 
                                                   error:&error];    
if(error)
{ 
    NSLog(@"Error: AudioSession cannot use speakers");
}

回答3:

let audioSession = AVAudioSession.sharedInstance()

    do {
        try audioSession.setCategory(AVAudioSession.Category.playAndRecord, mode: .spokenAudio, options: .defaultToSpeaker)
        try audioSession.setActive(true, options: .notifyOthersOnDeactivation)
    } catch {
        print("error.")
    }  

// paste this code in your viewLoad region

回答4:

Foundry’s solution together with this blog by Mario Diana has also allowed me to upgrade audio session set up code deprecated in iOS 7. My old code was based on AudioBufferPlayer by Matthijs Hollemans. Remember to add the AVFoundation.framework.