Android getMaxAmpliance（）始终返回0

我试图得到

声级压力

以

分贝

表示，但我总是得到

0

。（文本视图

的输出是-Infinity，但因为log（0）=-Infinity

Manifest.xml
中的权限：

<uses-permission android:name="android.permission.RECORD_AUDIO" />

但是什么都没有，仍然变得越来越强大-无限

我认为您需要按照开发人员说明调用recorder.prepare（）和recorder.start（）

更新您还必须设置输出文件（文件路径）

试试这个：

MediaRecorder recorder = new MediaRecorder();
    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
    recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    Timer timer = new Timer();
    timer.scheduleAtFixedRate(new RecorderTask(recorder), 0, 500);
    recorder.setOutputFile("/dev/null");

    try {
        recorder.prepare();
        recorder.start();
    } catch(IllegalStateException e)
    {
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }


}

private class RecorderTask extends TimerTask {
    TextView sound = (TextView) findViewById(R.id.decibel);
    private MediaRecorder recorder;

    public RecorderTask(MediaRecorder recorder) {
        this.recorder = recorder;
    }

    public void run() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                int amplitude = recorder.getMaxAmplitude();
                double amplitudeDb = 20 * Math.log10((double)Math.abs(amplitude)); 
                sound.setText("" + amplitudeDb);
            }
        });
    }
}

如果没有/32768，我得到的值在30分贝（我安静的房间）和88分贝（当我放大声的音乐时）之间


我想他们没问题
下面的代码适合我，需要设置“setAudioSamplingRate”和“setAudioEncodingBitRate”

recorder.GetMaxAmplium（）是否每次都返回0？@Mark Gilchrist是的。我正在两个不同的设备上进行尝试您是否尝试在“活动”中添加一个按钮并从UI线程获取值，以及为什么要调用runOnUIThread（）当你的任务不在后台时？你检查过录音是包含声音还是只有静默吗？你没有调用recorder.prepare（）或recorder.start（），我添加了recorder.prepare（）；recorder.start（）；但我只在日志中得到一个错误无法启动活动组件信息{beta_toolbox.pier.beta_toolbox/beta_toolbox.pier.beta_toolbox.SLP}：java.lang.IllegalStateException java.lang.IllegalStateException联机记录器.start（）；如果你将stacktrace粘贴到你的问题中，我可能会有更多的帮助。它是否说了一些类似于……由……引起的内容，整个stacktrace将更有帮助，你可以通过编辑itLet us将其添加到你的问题中。是的，实际上它是有效的，我也得到了该范围内的值。但我对操作不是很确定，我的意思是，很多问题在上一节课上，我看到有人说要得到db的值，我必须这样做：powerDb=20*log10（getAmplificate（）/referenceAmp）；_有4个问题可以让你理解：1）2）3）4）哦，我明白了，我只要有int-Amplificate=recorder.getMaxAmplificate（）；double AmplicatedB=20*Math.log10（（双）Math.abs（振幅））；以获得声级压力。非常感谢男士：D
MediaRecorder recorder = new MediaRecorder();
    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
    recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    recorder.setOutputFile("/dev/null");
    try {
        recorder.prepare();
    } catch (IOException e) {
        e.printStackTrace();
    }
    recorder.start();
    Timer timer = new Timer();
    timer.scheduleAtFixedRate(new RecorderTask(recorder), 0, 500);
    recorder.reset();
}
private class RecorderTask extends TimerTask {
    TextView risultato = (TextView) findViewById(R.id.decibel);
    private MediaRecorder recorder;

    public RecorderTask(MediaRecorder recorder) {
        this.recorder = recorder;
    }

    public double getAmplitude() {
        if (recorder != null)
            return  (recorder.getMaxAmplitude());
        else
            return 0;

    }

    public void run() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                int amplitude = recorder.getMaxAmplitude();
                double amplitudeDb = 20 * Math.log10(getAmplitude() / 32768);
                //double db = 20 * Math.log(recorder.getMaxAmplitude() / 2700.0);
                risultato.setText("" + amplitudeDb);
            }
        });
    }
}

MediaRecorder recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
recorder.setOutputFile(PATH_NAME);
recorder.prepare();
recorder.start();   // Recording is now started
 ...
recorder.stop();
recorder.reset();   // You can reuse the object by going 

MediaRecorder recorder = new MediaRecorder();
    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
    recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    Timer timer = new Timer();
    timer.scheduleAtFixedRate(new RecorderTask(recorder), 0, 500);
    recorder.setOutputFile("/dev/null");

    try {
        recorder.prepare();
        recorder.start();
    } catch(IllegalStateException e)
    {
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }


}

private class RecorderTask extends TimerTask {
    TextView sound = (TextView) findViewById(R.id.decibel);
    private MediaRecorder recorder;

    public RecorderTask(MediaRecorder recorder) {
        this.recorder = recorder;
    }

    public void run() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                int amplitude = recorder.getMaxAmplitude();
                double amplitudeDb = 20 * Math.log10((double)Math.abs(amplitude)); 
                sound.setText("" + amplitudeDb);
            }
        });
    }
}

 MediaRecorder recorder = new MediaRecorder();
 recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
 if (Build.VERSION.SDK_INT >= 10) {
  recorder.setAudioSamplingRate(44100);
  recorder.setAudioEncodingBitRate(96000);
  recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
  recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
} else {
  // older version of Android, use crappy sounding voice codec
   recorder.setAudioSamplingRate(8000);
   recorder.setAudioEncodingBitRate(12200);
   recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
   recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
}
recorder.setOutputFile(file.getAbsolutePath());
try {
 recorder.prepare();
 } catch (IOException e) {
throw new RuntimeException(e);
}