参考文章Android中实时获取音量分贝值详解：http://www.jb51.net/article/64806.htm

public class MediaRecorderDemo { private final String TAG = "MediaRecord"; private MediaRecorder mMediaRecorder; public static final int MAX_LENGTH = 1000 * 60 * 10;// 最大录音时长1000*60*10; private String filePath; public MediaRecorderDemo(){ this.filePath = "/dev/null"; } public MediaRecorderDemo(File file) { this.filePath = file.getAbsolutePath(); } private long startTime; private long endTime; /** * 开始录音 使用amr格式 * * 录音文件 * @return */ public void startRecord() { // 开始录音 /* ①Initial：实例化MediaRecorder对象 */ if (mMediaRecorder == null) mMediaRecorder = new MediaRecorder(); try { /* ②setAudioSource/setVedioSource */ mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);// 设置麦克风 /* ②设置音频文件的编码：AAC/AMR_NB/AMR_MB/Default 声音的（波形）的采样 */ mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT); /* * ②设置输出文件的格式：THREE_GPP/MPEG-4/RAW_AMR/Default THREE_GPP(3gp格式 * ，H263视频/ARM音频编码)、MPEG-4、RAW_AMR(只支持音频且音频编码要求为AMR_NB) */ mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); /* ③准备 */ mMediaRecorder.setOutputFile(filePath); mMediaRecorder.setMaxDuration(MAX_LENGTH); mMediaRecorder.prepare(); /* ④开始 */ mMediaRecorder.start(); // AudioRecord audioRecord. /* 获取开始时间* */ startTime = System.currentTimeMillis(); updateMicStatus(); Log.i("ACTION_START", "startTime" + startTime); } catch (IllegalStateException e) { Log.i(TAG, "call startAmr(File mRecAudioFile) failed!" + e.getMessage()); } catch (IOException e) { Log.i(TAG, "call startAmr(File mRecAudioFile) failed!" + e.getMessage()); } } /** * 停止录音 * */ public long stopRecord() { if (mMediaRecorder == null) return 0L; endTime = System.currentTimeMillis(); Log.i("ACTION_END", "endTime" + endTime); mMediaRecorder.stop(); mMediaRecorder.reset(); mMediaRecorder.release(); mMediaRecorder = null; Log.i("ACTION_LENGTH", "Time" + (endTime - startTime)); return endTime - startTime; } private final Handler mHandler = new Handler(); private Runnable mUpdateMicStatusTimer = new Runnable() { public void run() { updateMicStatus(); } }; /** * 更新话筒状态 * */ private int BASE = 1; private int SPACE = 100;// 间隔取样时间 private void updateMicStatus() { if (mMediaRecorder != null) { double ratio = (double)mMediaRecorder.getMaxAmplitude() /BASE; double db = 0;// 分贝 if (ratio > 1) db = 20 * Math.log10(ratio); Log.d(TAG,"分贝值："+db); mHandler.postDelayed(mUpdateMicStatusTimer, SPACE); } } }