Question

我有一个线程，它使用AudioTrack来合成一系列音符，并使用搜索栏来改变速度。

t = new Thread()
    {
        public void run()
        {
            setPriority(Thread.MAX_PRIORITY);

            int buffersize = AudioTrack.getMinBufferSize(sr, AudioFormat.CHANNEL_OUT_MONO,
                    AudioFormat.ENCODING_PCM_16BIT);

            audiotrack = new AudioTrack(AudioManager.STREAM_MUSIC, sr,
                    AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT,
                    buffersize, AudioTrack.MODE_STREAM);

            short samples[] = new short[buffersize];

            int amplitude = 10000;
            double twopi = 2*Math.PI;

            double ph = 0.0;


            audiotrack.play();
            double r = 1.0594630943593; //the 12th root of 2
            frequency=261.63;
            for(int k = 1; k<9; k++) //number of notes played
            {
                frequency*=r;
                for (int i = 0; i < 4+4*temposliderval; i++) //duration of each note, if i = 50, note duration = 12 seconds
                {

                    for (int j = 0; j < buffersize; j++)
                    {
                        samples[j] = (short) (amplitude * Math.sin(ph));
                        ph += twopi * frequency / sr;
                    }
                    audiotrack.write(samples, 0, buffersize);
                }
            }

            audiotrack.stop();
            audiotrack.release();

        }
    };


    //play button
    play = (Button)findViewById(R.id.play);
    play.setBackgroundResource(R.mipmap.play);
    play.setOnClickListener(new View.OnClickListener()
    {
        public void onClick(View v)
        {
            t.start();
        }
    });







    //stop button
    stop = (Button)findViewById(R.id.stop);
    stop.setBackgroundResource(R.mipmap.stop);
    stop.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            t.interrupt();
        }
    });

我希望能够在按下停止按钮时停止音频。调用t.interrupt（）不起作用，所以我想知道如何在按下停止按钮时正确停止线程。目标是能够在需要时停止音频，并且再次按下播放按钮时再次启动它。

Answer 1

最简单的方法可能是声明一个volatile成员变量：

private volatile boolean mStop = false;

两个线程都可以访问。你可以在线程循环内部轮询变量并在设置时停止循环，并在按下按钮时将变量设置为true。

Answer 2

我明白了！这种方法似乎没有列在其他任何地方，所以我一定很幸运：

简单地将线程放在一个新方法中，并在playbutton click上调用该方法，而不是试图阻止该线程，只需停止录音带的音频：

 play = (Button)findViewById(R.id.play);
    play.setBackgroundResource(R.mipmap.play);
    play.setOnClickListener(new View.OnClickListener()
    {
        public void onClick(View v)
        {
            playScale();
        }
    });







    //stop button
    stop = (Button)findViewById(R.id.stop);
    stop.setBackgroundResource(R.mipmap.stop);
    stop.setOnClickListener(new View.OnClickListener()
    {
        public void onClick(View v)
        {
            audiotrack.stop();
        }
    });

现在，每次点击播放按钮时，线程都会重新启动，尽管实际上已停止。

public void playScale()
{
    t = new Thread()
    {
        public void run()
        {
            t.setPriority(Thread.MAX_PRIORITY);

            int buffersize = AudioTrack.getMinBufferSize(sr, AudioFormat.CHANNEL_OUT_MONO,
                    AudioFormat.ENCODING_PCM_16BIT);

            audiotrack = new AudioTrack(AudioManager.STREAM_MUSIC, sr,
                    AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT,
                    buffersize, AudioTrack.MODE_STREAM);

            short samples[] = new short[buffersize];

            int amplitude = 10000;

            double twopi = 2 * Math.PI;

            double ph = 0.0;

            audiotrack.play();

            double r = 1.0594630943593; //the 12th root of 2

            frequency = 261.63;
            for (int k = 1; k < 9; k++) //number of notes played
            {
                frequency *= r;
                for (int i = 0; i < 4 + 4 * temposliderval; i++) //duration of each note, if i = 50, note duration = 12 seconds; minimum tempo = 60 bpm
                {
                    for (int j = 0; j < buffersize; j++)
                    {
                        samples[j] = (short) (amplitude * Math.sin(ph));
                        ph += twopi * frequency / sr;
                    }
                    audiotrack.write(samples, 0, buffersize);
                }
            }
        }
    };
    t.start();
}

android如何按下按钮按下音频线程？

2 个答案: