相当于iOS AVPlayer的exoplayer中的getBufferedPosition()

import com.google.android.exoplayer2.ExoPlayer;
import com.google.android.exoplayer2.ExoPlayerFactory;
import com.google.android.exoplayer2.SimpleExoPlayer;
import com.google.android.exoplayer2.source.MediaSource;
import com.google.android.exoplayer2.upstream.DefaultDataSourceFactory;
import com.google.android.exoplayer2.util.Util;

public class PlayerActivity extends AppCompatActivity {
    private SimpleExoPlayer player;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_player);

        player = ExoPlayerFactory.newSimpleInstance(this);
        PlayerView playerView = findViewById(R.id.player_view);
        playerView.setPlayer(player);

        DefaultDataSourceFactory dataSourceFactory = new DefaultDataSourceFactory(this, Util.getUserAgent(this, "yourAppName"));
        MediaSource mediaSource = new ProgressiveMediaSource.Factory(dataSourceFactory).createMediaSource(Uri.parse("https://your-media-url.mp4"));

        player.prepare(mediaSource);
        player.setPlayWhenReady(true);

        player.addListener(new Player.EventListener() {
            @Override
            public void onBufferingUpdate(int periodId, int bufferPercentage) {
                long bufferedPosition = player.getBufferedPosition();
                // 更新缓冲进度条
                updateBufferedProgressBar(bufferedPosition);
            }
        });
    }

    private void updateBufferedProgressBar(long bufferedPosition) {
        // 实现更新缓冲进度条的逻辑
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (player != null) {
            player.release();
            player = null;
        }
    }
}