Android Exoplayer: getAudioComponent为空

Question

我正在与exoplayer流式音频，我想有一个按钮，以静音和取消静音的音频。

我正在使用这些依赖项：

implementation 'com.google.android.exoplayer:exoplayer-core:2.10.5'
implementation 'com.google.android.exoplayer:exoplayer-dash:2.10.5'
implementation 'com.google.android.exoplayer:exoplayer-ui:2.10.5'

播放器初始化代码：

private void initializePlayer() {
        player = ExoPlayerFactory.newSimpleInstance(context);
        playerView.setPlayer(player);
        playerView.setControllerHideOnTouch(false);
        playerView.setControllerShowTimeoutMs(0);
        Uri uri = Uri.parse(mediaUrl);

        MediaSource mediaSource = buildMediaSource(uri);

        player.addListener(playbackStateListener);
        player.setPlayWhenReady(playWhenReady);
        player.seekTo(currentWindow, playbackPosition);
        player.prepare(mediaSource, false, false);

    }  

buildMediaSource：

private MediaSource buildMediaSource(Uri uri) {
        DataSource.Factory dataSourceFactory =
                new DefaultDataSourceFactory(context, "exoplayer-codelab");
        return new ProgressiveMediaSource.Factory(dataSourceFactory)
                .createMediaSource(uri);
    }

这就是我尝试静音和取消静音的方法：

    float currentAudioLevel = player.getAudioComponent().getVolume();
            mute.setOnClickListener(view -> {
                    if(!muteAudio) {
                        Objects.requireNonNull(player.getAudioComponent()).setVolume(0);
                        mute.setImageDrawable(ContextCompat.getDrawable(context,R.drawable.ic_volume_off));
                        muteAudio = true;
                    }else{
                        Objects.requireNonNull(player.getAudioComponent()).setVolume(currentAudioLevel);
                        mute.setImageDrawable(ContextCompat.getDrawable(context,R.drawable.ic_volume_on));
                        muteAudio = false;
                    }
            });

getAudioComponent抛出空指针异常：

 Attempt to invoke interface method 
   'com.google.android.exoplayer2.Player$AudioComponent 
    com.google.android.exoplayer2.Player.getAudioComponent()' on a null object reference

音频流正常，所有控件都正常工作，但我无法获取或设置音量。

Answer 1

只需使用player.setVolume(0.0f);即可

我建议先获取当前音量，然后将其静音。当你要取消静音时，你可以给用户相同的音量。

float currentvolume;
currentvolume = player.getVolume();
player.setVolume(0.0f);