Android提高第十篇之AudioRecord实现"助听器"

Android可以通过MediaRecorder和AudioRecord这两个工具来实现录音，MediaRecorder直接把麦克风的数据存到文 件，并且能够直接进行编码(如AMR,MP3等)，而AudioRecord则是读取麦克风的音频流。本文使用AudioRecord读取音频流，使用 AudioTrack播放音频流，通过“边读边播放”以及增大音量的方式来实现一个简单的助听器程序。

PS：由于目前的Android模拟器还不支持AudioRecord，因此本程序需要编译之后放到真机运行。

先贴出本文程序运行截图：

PS：程序音量调节只是程序内部调节音量而已，要调到最大音量还需要手动设置系统音量。

使用AudioRecord必须要申请许可，在AndroidManifest.xml里面添加这句：

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

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

main.xml的源码如下：

 <? xml   version = "1.0"   encoding = "utf-8" ?>
 < LinearLayout   xmlns:android = "http://schemas.android.com/apk/res/android"
     android:orientation = "vertical"   android:layout_width = "fill_parent"
     android:layout_height = "fill_parent" >

     < Button   android:layout_height = "wrap_content"   android:id = "@+id/btnRecord"
         android:layout_width = "fill_parent"   android:text = "开始边录边放" > </ Button >
     < Button   android:layout_height = "wrap_content"
         android:layout_width = "fill_parent"   android:text = "停止"   android:id = "@+id/btnStop" > </ Button >
     < Button   android:layout_height = "wrap_content"   android:id = "@+id/btnExit"
         android:layout_width = "fill_parent"   android:text = "退出" > </ Button >
     < TextView   android:id = "@+id/TextView01"   android:layout_height = "wrap_content"
         android:text = "程序音量调节"   android:layout_width = "fill_parent" > </ TextView >
     < SeekBar   android:layout_height = "wrap_content"   android:id = "@+id/skbVolume"
         android:layout_width = "fill_parent" > </ SeekBar >

 </ LinearLayout >

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <Button android:layout_height="wrap_content" android:id="@+id/btnRecord" android:layout_width="fill_parent" android:text="开始边录边放"></Button> <Button android:layout_height="wrap_content" android:layout_width="fill_parent" android:text="停止" android:id="@+id/btnStop"></Button> <Button android:layout_height="wrap_content" android:id="@+id/btnExit" android:layout_width="fill_parent" android:text="退出"></Button> <TextView android:id="@+id/TextView01" android:layout_height="wrap_content" android:text="程序音量调节" android:layout_width="fill_parent"></TextView> <SeekBar android:layout_height="wrap_content" android:id="@+id/skbVolume" android:layout_width="fill_parent"></SeekBar> </LinearLayout>

testRecord.java的源码如下：

 package  com.testRecord;

 import  android.app.Activity;
 import  android.media.AudioFormat;
 import  android.media.AudioManager;
 import  android.media.AudioRecord;
 import  android.media.AudioTrack;
 import  android.media.MediaRecorder;
 import  android.os.Bundle;
 import  android.view.View;
 import  android.widget.Button;
 import  android.widget.SeekBar;
 import  android.widget.Toast;

 public   class  testRecord  extends  Activity {
     /** Called when the activity is first created. */
     Button btnRecord, btnStop, btnExit;
     SeekBar skbVolume;//调节音量
     boolean  isRecording =  false ; //是否录放的标记
     static   final   int  frequency =  44100 ;
     static   final   int  channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
     static   final   int  audioEncoding = AudioFormat.ENCODING_PCM_16BIT;
     int  recBufSize,playBufSize;
     AudioRecord audioRecord;
     AudioTrack audioTrack;

     @Override
     public   void  onCreate(Bundle savedInstanceState) {
         super .onCreate(savedInstanceState);
         setContentView(R.layout.main);
         setTitle("助听器" );
         recBufSize = AudioRecord.getMinBufferSize(frequency,
                 channelConfiguration, audioEncoding);

         playBufSize=AudioTrack.getMinBufferSize(frequency,
                 channelConfiguration, audioEncoding);
         // -----------------------------------------
         audioRecord = new  AudioRecord(MediaRecorder.AudioSource.MIC, frequency,
                 channelConfiguration, audioEncoding, recBufSize);

         audioTrack = new  AudioTrack(AudioManager.STREAM_MUSIC, frequency,
                 channelConfiguration, audioEncoding,
                 playBufSize, AudioTrack.MODE_STREAM);
         //------------------------------------------
         btnRecord = (Button) this .findViewById(R.id.btnRecord);
         btnRecord.setOnClickListener(new  ClickEvent());
         btnStop = (Button) this .findViewById(R.id.btnStop);
         btnStop.setOnClickListener(new  ClickEvent());
         btnExit = (Button) this .findViewById(R.id.btnExit);
         btnExit.setOnClickListener(new  ClickEvent());
         skbVolume=(SeekBar)this .findViewById(R.id.skbVolume);
         skbVolume.setMax(100 ); //音量调节的极限
         skbVolume.setProgress(70 ); //设置seekbar的位置值
         audioTrack.setStereoVolume(0 .7f,  0 .7f); //设置当前音量大小
         skbVolume.setOnSeekBarChangeListener(new  SeekBar.OnSeekBarChangeListener() {

             @Override
             public   void  onStopTrackingTouch(SeekBar seekBar) {
                 float  vol=( float )(seekBar.getProgress())/( float )(seekBar.getMax());
                 audioTrack.setStereoVolume(vol, vol);//设置音量
             }

             @Override
             public   void  onStartTrackingTouch(SeekBar seekBar) {
                 // TODO Auto-generated method stub
             }

             @Override
             public   void  onProgressChanged(SeekBar seekBar,  int  progress,
                     boolean  fromUser) {
                 // TODO Auto-generated method stub
             }
         });
     }

     @Override
     protected   void  onDestroy() {
         super .onDestroy();
         android.os.Process.killProcess(android.os.Process.myPid());
     }

     class  ClickEvent  implements  View.OnClickListener {

         @Override
         public   void  onClick(View v) {
             if  (v == btnRecord) {
                 isRecording = true ;
                 new  RecordPlayThread().start(); // 开一条线程边录边放
             } else   if  (v == btnStop) {
                 isRecording = false ;
             } else   if  (v == btnExit) {
                 isRecording = false ;
                 testRecord.this .finish();
             }
         }
     }

     class  RecordPlayThread  extends  Thread {
         public   void  run() {
             try  {
                 byte [] buffer =  new   byte [recBufSize];
                 audioRecord.startRecording();//开始录制
                 audioTrack.play();//开始播放

                 while  (isRecording) {
                     //从MIC保存数据到缓冲区
                     int  bufferReadResult = audioRecord.read(buffer,  0 ,
                             recBufSize);

                     byte [] tmpBuf =  new   byte [bufferReadResult];
                     System.arraycopy(buffer, 0 , tmpBuf,  0 , bufferReadResult);
                     //写入数据即播放
                     audioTrack.write(tmpBuf, 0 , tmpBuf.length);
                 }
                 audioTrack.stop();
                 audioRecord.stop();
             } catch  (Throwable t) {
                 Toast.makeText(testRecord.this , t.getMessage(),  1000 );
             }
         }
     };
 }