Android录制声音(一)Recorder

再看Android SDK的录制声音的例子时看见文章比较短就翻译了一下，请大家提出宝贵意见：

Android SDK \docs\guide\topics\media\audio-capture.html 的翻译

音频录制

Android多媒体框架支持对常见音频的录制和编码，如果硬件支持，可以使用 MediaRecorder APIs 来非常方便的编写音频程序。

通过学习这篇文档，你可编写应用程序通过设备的麦克来录制声音，并且保持和播放声音。

  注意：Android模拟器不支持录制声音的功能，必须有实际设备。

运行录制声音程序

   音频的录制要比音频或者视频的播放要复杂,但是相对也比较简单，课遵循以下步骤：

1.      创建MediaRecorder实例: android.media.MediaRecorder

2.      设置音频来源：MediaRecorder.setAudioSource();

3.      设置输出音频格式：MediaRecorder.setOutputFormat();

4.      设置输出文件名:MediaRecorder.setOutputFile();

5.      设置输出编码格式:MediaRecorder.setAudioEncorder();

6.      在开始录制之前调用MediaRecorder.prepare();

7.      开始录制声音,调用：MediaRecorder.start();

8.      停止录制声音，调用：MediaRecorder.stop();

9.      当录制完声音的时候，调用MediaRecorder.release()来释放占用的相关资源

例子：录制音频并播放

下面的例子展示了怎样录制并播放声音

这个APP需要添加两个权限

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

/*
* The application needs to have the permission to write to external storage
* if the output file is written to the external storage, and also the
* permission to record audio. These permissions must be set in the
* application's AndroidManifest.xml file, with something like:
*
* <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
* <uses-permission android:name="android.permission.RECORD_AUDIO" />
*
*/
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 classAudioRecordTestextendsActivity
{
    private staticfinalString LOG_TAG="AudioRecordTest";
    private staticString mFileName=null;

    private RecordButton mRecordButton=null;
    private MediaRecorder mRecorder=null;

    private PlayButton   mPlayButton=null;
    private MediaPlayer   mPlayer=null;

    private void onRecord(boolean start){
        if (start){
            startRecording();
        } else{
            stopRecording();
        }
    }

    private void onPlay(boolean start){
        if (start){
            startPlaying();
        } else{
            stopPlaying();
        }
    }

    private void startPlaying(){
        mPlayer = newMediaPlayer();
        try {
            mPlayer.setDataSource(mFileName);
            mPlayer.prepare();
            mPlayer.start();
        } catch(IOException e){
            Log.e(LOG_TAG,"prepare() failed");
        }
    }

    private void stopPlaying(){
        mPlayer.release();
        mPlayer = null;
    }

    private void startRecording(){
        mRecorder = newMediaRecorder();
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mRecorder.setOutputFile(mFileName);
        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;
    }

    class RecordButtonextendsButton{
        boolean mStartRecording=true;

        OnClickListener clicker=newOnClickListener(){
            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);
        }
    }

    class PlayButtonextendsButton{
        boolean mStartPlaying = true;

        OnClickListener clicker=newOnClickListener(){
            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);
        }
    }

    public AudioRecordTest(){
        mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
        mFileName += "/audiorecordtest.3gp";
    }

    @Override
    public void onCreate(Bundle icicle){
        super.onCreate(icicle);

        LinearLayout ll = newLinearLayout(this);
        mRecordButton = new RecordButton(this);
        ll.addView(mRecordButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));
        mPlayButton = newPlayButton(this);
        ll.addView(mPlayButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));
        setContentView(ll);
    }

    @Override
    public void onPause(){
        super.onPause();
        if (mRecorder!=null){
            mRecorder.release();
            mRecorder = null;
        }

        if (mPlayer!=null){
            mPlayer.release();
            mPlayer = null;
        }
    }
}

这是SDK的中带的代码，我已经在自己的手机上成功运行没有任何错误！