Question

我正在使用的Android应用程序使用AudioTrack来播放音符。这会创建一个新的线程，对于每个被按下的音符都不会结束（直到我的应用程序崩溃）。

来自A组的

：

AudioGenerator.playSound(AudioGenerator.genTone((tone)));

AudioGenerator类：

import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;

public class AudioGenerator {

private static final int sampleRate = 8000;
private static final double duration = 1; // seconds
private static double dnumSamples = duration * sampleRate;
private static final int numSamples = (int) dnumSamples;
private static double sample[] = new double[numSamples];
private static byte generatedSnd[] = new byte[2*numSamples];

  static void playSound(byte[] sound){
      final byte[] play = sound;
      (new Thread(new Runnable() {
            @Override
              public void run() {
                      AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, 8000, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT, numSamples, AudioTrack.MODE_STATIC);
                      audioTrack.write(play, 0, play.length);
                      audioTrack.play();
              }})).start();
  } 

  static byte[] genTone(double freq){
      for (int i = 0; i < numSamples; ++i) sample[i] = Math.sin(freq * 2 * Math.PI * i / (sampleRate));
      // convert to 16 bit pcm sound array
      // assumes the sample buffer is normalised.
      int idx = 0;
      int i = 0;
      int ramp = numSamples/20; // Amplitude ramp as a percent of sample count
      for (i = 0; i< ramp; ++i) {                                     // Ramp amplitude up (to avoid clicks)
          double dVal = sample[i];
                                                                      // Ramp up to maximum
          final short val = (short) ((dVal * 32767 * i/ramp));
                                                                      // in 16 bit wav PCM, first byte is the low order byte
          generatedSnd[idx++] = (byte) (val & 0x00ff);
          generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
      }
      for (i = i; i< numSamples - ramp; ++i) {                        // Max amplitude for most of the samples
          double dVal = sample[i];
                                                                      // scale to maximum amplitude
          final short val = (short) ((dVal * 32767));
                                                                      // in 16 bit wav PCM, first byte is the low order byte
          generatedSnd[idx++] = (byte) (val & 0x00ff);
          generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
      }

      for (i = i; i< numSamples; ++i) {                               // Ramp amplitude down
          double dVal = sample[i];
                                                                      // Ramp down to zero
          final short val = (short) ((dVal * 32767 * (numSamples-i)/ramp ));
                                                                      // in 16 bit wav PCM, first byte is the low order byte
          generatedSnd[idx++] = (byte) (val & 0x00ff);
          generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
      }
      return generatedSnd;
  }

}

我无法弄清楚我错过了什么。请帮忙

Answer 1

尝试修改playTone和playSamples方法：

private void playTone(final int freq, final double duration)
{
    Thread thread = new Thread(new Runnable()
    {
        public void run()
        {
            genTone(freq, duration);
        }
    });

    thread.start();
}


private void playSamples(byte[] generatedSound, int sampleRate, int numSamples)
{
    AudioTrack audioTrack = null;
    try
    {
        audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, sampleRate, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT,
                (int) numSamples * 2, AudioTrack.MODE_STATIC);

        // Load the track
        audioTrack.write(generatedSound, 0, generatedSound.length);
        audioTrack.play();
    }
    catch (Exception e)
    {
        Log.e(MainActivity.DEBUG_TAG, "Audio track exception: " + e.getMessage());
    }

    int x = 0;
    do
    { // Montior playback to find when done
        if (audioTrack != null)
            x = audioTrack.getPlaybackHeadPosition();
        else
            x = numSamples;
    }
    while (x < numSamples);
    audioTrack.release();
}

最后，将playSamples(generatedSnd, sampleRate, numSamples);添加到genTone方法的末尾;

线程永远不会结束

1 个答案: