Android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>

 

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);    
            }    
        }    
    };    
}