android 录音波形图不持续出现

Question

以下是修改的一段画录音波形图的代码，数据是jni层录音返回的一个byte数组，在录音的时候，只是画了一小段波形就不再继续，不知道哪里出现了问题

class RecordTask extends AsyncTask {

    private int recBufSize;
    private byte[] pcmData;
    private SurfaceView sfv;// 画板
    private Paint mPaint;// 画笔

    public RecordTask(byte[] pcmData, int recBufSize, SurfaceView sfv,
            Paint mPaint) {
        this.pcmData = pcmData;
        this.recBufSize = recBufSize;
        this.sfv = sfv;
        this.mPaint = mPaint;
    }

    @Override
    protected Object doInBackground(Object... params) {
        try {
             byte[] buffer = new byte[1764];
            ByteArrayInputStream arrayInputStream = new ByteArrayInputStream(
                    pcmData);
            while (isRecording) {
                int readsize = arrayInputStream.read(buffer,0,1764);
                synchronized (inBuf) {
                    // 添加数据
                    int len = readsize / rateX;
                    for (int i = 0; i < len; i += rateX) {
                        inBuf.add((short) ((0x0000 | buffer[i + 1]) << 8 | buffer[i]));
                    }
                }
                publishProgress();
            }
        } catch (Throwable t) {
        }
        return null;
    }

    @Override
    protected void onProgressUpdate(Object... values) {
        long time = new Date().getTime();
        if (time - c_time >= draw_time) {
            c_time = new Date().getTime();
            SimpleDraw(inBuf, baseLine);
        }
        super.onProgressUpdate(values);
    }

    void SimpleDraw(ArrayList<Short> inBuf, int baseLine) {
        if (rateY == 0) {
            rateY = 50000 / sfv.getHeight();
            baseLine = sfv.getHeight() / 2;
        }
        Canvas canvas = sfv.getHolder().lockCanvas(
                new Rect(0, 0, sfv.getWidth(), sfv.getHeight()));// 关键:获取画布
        canvas.drawColor(Color.BLACK);// 清除背景
        int start = sfv.getWidth() - inBuf.size() * divider;
        int py = baseLine;
        if (inBuf.size() > 0)
            py += inBuf.get(0) / rateY;
        int y;
        canvas.drawLine(0, baseLine, start - divider, baseLine, mPaint);
        for (int i = 0; i < inBuf.size(); i++) {
            y = inBuf.get(i) / rateY + baseLine;// 调节缩小比例，调节基准线
            canvas.drawLine(start + (i - 1) * divider, py, start + i
                    * divider, y, mPaint);
            py = y;
        }
        sfv.getHolder().unlockCanvasAndPost(canvas);// 解锁画布，提交画好的图像
    }
}

Answer 1

单步调试一下，容易找出问题，或者加几个提示信息，判断一下哪里出问题