Android提高第十篇之AudioRecord实现"助听器"

http://blog.csdn.net/hellogv/archive/2010/11/22/6026455.aspx
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>

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>

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);              }          }      };  }

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