Android多媒体框架包含获取和编码多种音频格式的支持，所以你可以轻松地把音频合并到你的应用中．如果设备支持，你可以使用MediaRecorder APIs 进行录音．
本章向你展示如何写一个应用从设备上的microphone获取音频，然后保存并回放．
注：Android模拟器不具有录音的能力，但是真实的设备一般都具有此功能．
执行音频获取
从设备获取音频比回放音频或视频要复杂一点，但是也还算简单：
- 创建一个android.media.MediaRecorder的新实例．
- 使用MediaRecorder.setAudioSource()设置音频源，一般要使用MediaRecorder.AudioSource.MIC.
- 使用MediaRecorder.setOutputFormat()设置输出文件的格式．
- 使用MediaRecorder.setOutputFile()设置输出文件的名字．
- 使用MediaRecorder.setAudioEncoder()设置音频编码．
- 调用MediaRecorder 实例的MediaRecorder.prepare()．
- MediaRecorder.start()开始获取音频．
- 调用MediaRecorder.stop().停止．
- 当你用完MediaRecorder实例后，调用MediaRecorder.release()，就会立即释放资源．
示例：录音并回放录音
下面的例子演示了如何设置，开始以及停止音频获取，以及回放录制的文件．
/* * 如果输出文件被写入外部存储， * 本应用需要具有写外部存储的权限, * 还要具有录音的权限．这些权限必须 * 在AndroidManifest.xml 文件中声明，像这样： * ** * */package com.android.audiorecordtest;import android.app.Activity;import android.widget.LinearLayout;import android.os.Bundle;import android.os.Environment;import android.view.ViewGroup;import android.widget.Button;import android.view.View;import android.view.View.OnClickListener;import android.content.Context;import android.util.Log;import android.media.MediaRecorder;import android.media.MediaPlayer;import java.io.IOException;public class AudioRecordTest extends Activity{ private static final String LOG_TAG = "AudioRecordTest"; private static String mFileName = null; //录音按钮 private RecordButton mRecordButton = null; private MediaRecorder mRecorder = null; //回放按钮 private PlayButton mPlayButton = null; private MediaPlayer mPlayer = null; //当录音按钮被click时调用此方法，开始或停止录音 private void onRecord(boolean start) { if (start) { startRecording(); } else { stopRecording(); } } //当播放按钮被click时调用此方法，开始或停止播放 private void onPlay(boolean start) { if (start) { startPlaying(); } else { stopPlaying(); } } private void startPlaying() { mPlayer = new MediaPlayer(); try { //设置要播放的文件 mPlayer.setDataSource(mFileName); mPlayer.prepare(); //播放之 mPlayer.start(); } catch (IOException e) { Log.e(LOG_TAG, "prepare() failed"); } } //停止播放 private void stopPlaying() { mPlayer.release(); mPlayer = null; } private void startRecording() { mRecorder = new MediaRecorder(); //设置音源为Micphone mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC); //设置封装格式 mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP); mRecorder.setOutputFile(mFileName); //设置编码格式 mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); try { mRecorder.prepare(); } catch (IOException e) { Log.e(LOG_TAG, "prepare() failed"); } mRecorder.start(); } private void stopRecording() { mRecorder.stop(); mRecorder.release(); mRecorder = null; } //定义录音按钮 class RecordButton extends Button { boolean mStartRecording = true; OnClickListener clicker = new OnClickListener() { public void onClick(View v) { onRecord(mStartRecording); if (mStartRecording) { setText("Stop recording"); } else { setText("Start recording"); } mStartRecording = !mStartRecording; } }; public RecordButton(Context ctx) { super(ctx); setText("Start recording"); setOnClickListener(clicker); } } //定义播放按钮 class PlayButton extends Button { boolean mStartPlaying = true; OnClickListener clicker = new OnClickListener() { public void onClick(View v) { onPlay(mStartPlaying); if (mStartPlaying) { setText("Stop playing"); } else { setText("Start playing"); } mStartPlaying = !mStartPlaying; } }; public PlayButton(Context ctx) { super(ctx); setText("Start playing"); setOnClickListener(clicker); } } //构造方法 public AudioRecordTest() { mFileName = Environment.getExternalStorageDirectory().getAbsolutePath(); mFileName += "/audiorecordtest.3gp"; } @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); //构造界面 LinearLayout ll = new LinearLayout(this); mRecordButton = new RecordButton(this); ll.addView(mRecordButton, new LinearLayout.LayoutParams( ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, 0)); mPlayButton = new PlayButton(this); ll.addView(mPlayButton, new LinearLayout.LayoutParams( ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, 0)); setContentView(ll); } @Override public void onPause() { super.onPause(); //Activity暂停时释放录音和播放对象 if (mRecorder != null) { mRecorder.release(); mRecorder = null; } if (mPlayer != null) { mPlayer.release(); mPlayer = null; } }}