Android编程之播放器MediaPlayer实现均衡器效果示例

public class AudioFxDemo extends Activity {
  private static final String TAG = "AudioFxDemo";
  private static final float VISUALIZER_HEIGHT_DIP = 50f;
  // 定义播放器
  private MediaPlayer mMediaPlayer;
  // 定义系统的频谱
  private Visualizer mVisualizer;
  // 定义系统的均衡器
  private Equalizer mEqualizer;
  private LinearLayout mLinearLayout;
  private VisualizerView mVisualizerView;
  private TextView mStatusTextView;
  @Override
  public void onCreate(Bundle bundle) {
    super.onCreate(bundle);
    // 音量控制
    setVolumeControlStream(AudioManager.STREAM_MUSIC);
    mStatusTextView = new TextView(this);
    mLinearLayout = new LinearLayout(this);
    mLinearLayout.setOrientation(LinearLayout.VERTICAL);
    mLinearLayout.addView(mStatusTextView);
    setContentView(mLinearLayout);
    // 创建MediaPlayer对象
    mMediaPlayer = MediaPlayer.create(this, R.raw.test_cbr);
    Log.d(TAG,
        "MediaPlayer audio session ID: "
            + mMediaPlayer.getAudioSessionId());
    // 设置频谱显示
    setupVisualizerFxAndUI();
    // 设置示波器显示
    setupEqualizerFxAndUI();
    // Make sure the visualizer is enabled only when you actually want to
    // receive data, and
    // when it makes sense to receive data.
    mVisualizer.setEnabled(true);
    // When the stream ends, we don't need to collect any more data. We
    // don't do this in
    // setupVisualizerFxAndUI because we likely want to have more,
    // non-Visualizer related code
    // in this callback.
    mMediaPlayer
        .setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
          public void onCompletion(MediaPlayer mediaPlayer) {
            mVisualizer.setEnabled(false);
            mStatusTextView.setText("播放结束");
          }
        });
    mMediaPlayer.start();
    mStatusTextView.setText("正在播放中");
  }
  private void setupEqualizerFxAndUI() {
    // Create the Equalizer object (an AudioEffect subclass) and attach it
    // to our media player,
    // with a default priority (0).
    mEqualizer = new Equalizer(0, mMediaPlayer.getAudioSessionId());
    mEqualizer.setEnabled(true);
    TextView eqTextView = new TextView(this);
    eqTextView.setText("Equalizer:");
    mLinearLayout.addView(eqTextView);
    short bands = mEqualizer.getNumberOfBands();
    final short minEQLevel = mEqualizer.getBandLevelRange()[0];
    final short maxEQLevel = mEqualizer.getBandLevelRange()[1];
    for (short i = 0; i = 3) {
      type = 0;
    }
    return true;
  }
  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    if (bytes == null) {
      return;
    }
    // 绘制黑色背景
    canvas.drawColor(Color.BLACK);
    // 使用rect对象记录该组件的宽度和高度
    rect.set(0, 0, getWidth(), getHeight());
    switch (type) {
    // 绘制块状的波形图
    case 0:
      for (int i = 0; i