监控麦克风音量~~

VolumeRecord.java

package com.example.ipcjs.voicedemo;

import android.content.Context;
import android.media.MediaRecorder;
import android.os.Environment;
import android.os.Handler;

import java.io.File;
import java.io.IOException;

/**
 * Created by ipcjs on 2015/5/26.
 */
public class VolumeRecord {

    private static final int MAX_AMPLITUDE = 32767;
    private String mFilePath;

    public interface VolumeCallback {
        void onVolumeCallback(int progress);
    }

    private VolumeCallback mVolumeCallback;
    private MediaRecorder mMediaRecorder;
    private Context mContext;

    public VolumeRecord(Context context, VolumeCallback volumeCallback) {
        mContext = context;
        mVolumeCallback = volumeCallback;
        if (mContext.getExternalCacheDir() != null) {
            mFilePath = mContext.getExternalCacheDir().getAbsolutePath();
        } else {
            mFilePath = Environment.getExternalStorageState();
        }
        mFilePath += "/" + getClass().getSimpleName() + ".3gp";
    }

    public boolean isRecording() {
        return mMediaRecorder != null;
    }

    public boolean start() {
        if (isRecording()) {
            return false;
        }
        mMediaRecorder = new MediaRecorder();
        mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        mMediaRecorder.setOutputFile(mFilePath);
        try {
            mMediaRecorder.prepare();
        } catch (IOException e) {
            e.printStackTrace();
            mMediaRecorder = null;
            return false;
        }
        mMediaRecorder.start();
        updateUi();
        return true;
    }

    public void stop() {
        if (isRecording()) {
            mMediaRecorder.stop();
            mMediaRecorder.release();
            mMediaRecorder = null;
            new File(mFilePath).delete();
        }
    }

    private void updateUi() {
        if (!isRecording()) {
            return;
        }
        int maxAmplitude = mMediaRecorder.getMaxAmplitude();
        if (mVolumeCallback != null) {
            mVolumeCallback.onVolumeCallback((int) (100f * maxAmplitude / MAX_AMPLITUDE + 0.5));
        }
        mHandler.postDelayed(mUpdateUiRunnable, 100);
    }

    private Runnable mUpdateUiRunnable = new Runnable() {
        @Override
        public void run() {
            updateUi();
        }
    };
    private Handler mHandler = new Handler();
}

权限：

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