如何指定内部扬声器来播放音频文件？

Question

In my Android app, I want to play sounds on the phone internal speakers even when the user is connected to the device through a Bluetooth device or other external speakers. Can this be done?

Answer 1

I came up with way of playing audio on the phone speakers even when I have a connected Bluetooth audio device:

fun createPhoneSpeakerPreferredPlayer(context: Context, resource: Int): MediaPlayer{
    val mediaPlayer = MediaPlayer.create(context, resource)
    val audioDeviceType = if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) AudioDeviceInfo.TYPE_BUILTIN_SPEAKER_SAFE else AudioDeviceInfo.TYPE_BUILTIN_SPEAKER
    val audioManager = context.getSystemService(Context.AUDIO_SERVICE) as AudioManager
    val devices = audioManager.getDevices(AudioManager.GET_DEVICES_OUTPUTS)
    //create mapped devices variable to allow better logging.  The devices collection is not being serialized well (or at all)
    val mappedDevices = (devices.map {
        @Suppress("unused")
        object {
        val id = it.id
        val type = it.type
        val productName = it.productName
    }})
    val jsonRepresentation = Gson().toJson(mappedDevices)
    Log.d(Tag, "devices: $jsonRepresentation")
    val playbackDevice = devices.firstOrNull { it.type == audioDeviceType }
    Log.d(Tag, "selectedDevice: {id=${playbackDevice?.id}}, type=\"${playbackDevice?.type}\", productName=\"${playbackDevice?.productName}\"")
    mediaPlayer.preferredDevice = playbackDevice
    return mediaPlayer
}

to use that method and play audio:

val mediaPlayer = createPhoneSpeakerPreferredPlayer(this.context, R.raw.myAudioId)
mediaPlayer.looping = true
mediaPlayer.start()

This seems to work if I have a Bluetooth speaker connected, but once I start playing audio in the background, like watching Netflix, or listening to a podcast, the audio no longer plays on the phone speaker.

Here is a sample app I made with two buttons. One to play music through the phone speaker and one to play through whatever speaker is connected:

https://github.com/danwize/play-sound-android/blob/main/SoundPlayer/app/src/main/java/com/example/soundplayer/MainActivity.kt

I'm seeing that the first time I create a media player and play sound this way, the sound does play on the phone speakers. The second audio plays on the Bluetooth speaker. When I'm not playing any video or music, but still connected to a Bluetooth device, both my sounds play on the phone speakers. Here are the logs to show that I am correctly setting the preferred device:

2022-09-07 11:21:33.969 6101-6101/com.myApp D/MediaPlayerExtensions: devices: [{"id":2,"productName":"Pixel 3","type":1},{"id":3,"productName":"Pixel 3","type":2},{"id":11,"productName":"Pixel 3","type":18},{"id":369,"productName":"Jabra Elite 85h","type":8},{"id":363,"productName":"Jabra Elite 85h","type":7}]
2022-09-07 11:21:33.969 6101-6101/com.myApp D/MediaPlayerExtensions: selectedDevice: {id=3}, type="2", productName="Pixel 3"
2022-09-07 11:22:14.290 6101-6101/com.myApp D/MediaPlayerExtensions: devices: [{"id":2,"productName":"Pixel 3","type":1},{"id":3,"productName":"Pixel 3","type":2},{"id":11,"productName":"Pixel 3","type":18},{"id":369,"productName":"Jabra Elite 85h","type":8},{"id":363,"productName":"Jabra Elite 85h","type":7}]
2022-09-07 11:22:14.290 6101-6101/com.myApp D/MediaPlayerExtensions: selectedDevice: {id=3}, type="2", productName="Pixel 3"