本文來自 http://blog.csdn.net/hellogv/ ，引用必須注明出處！

Android可以通過MediaRecorder和AudioRecord這兩個工具來實現錄音，MediaRecorder直接把麥克風的數據存到文件，并且能夠直接進行編碼(如AMR,MP3等)，而AudioRecord則是讀取麥克風的音頻流。本文使用AudioRecord讀取音頻流，使用AudioTrack播放音頻流，通過“邊讀邊播放”以及增大音量的方式來實現一個簡單的助聽器程序。

PS：由于目前的Android模擬器還不支持AudioRecord，因此本程序需要編譯之后放到真機運行。

先貼出本文程序運行截圖：

PS：程序音量調節只是程序內部調節音量而已，要調到最大音量還需要手動設置系統音量。

使用AudioRecord必須要申請許可，在AndroidManifest.xml里面添加這句：

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

main.xml的源碼如下：

<?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="開始邊錄邊放"></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="程序音量調節" 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的源碼如下：

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;//調節音量 boolean isRecording = false;//是否錄放的標記 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("助聽器"); 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);//音量調節的極限 skbVolume.setProgress(70);//設置seekbar的位置值 audioTrack.setStereoVolume(0.7f, 0.7f);//設置當前音量大小 skbVolume.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { @Override public void onStopTrackingTouch(SeekBar seekBar) { float vol=(float)(seekBar.getProgress())/(float)(seekBar.getMax()); audioTrack.setStereoVolume(vol, vol);//設置音量 } @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();// 開一條線程邊錄邊放 } 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();//開始錄制 audioTrack.play();//開始播放 while (isRecording) { //從MIC保存數據到緩沖區 int bufferReadResult = audioRecord.read(buffer, 0, recBufSize); byte[] tmpBuf = new byte[bufferReadResult]; System.arraycopy(buffer, 0, tmpBuf, 0, bufferReadResult); //寫入數據即播放 audioTrack.write(tmpBuf, 0, tmpBuf.length); } audioTrack.stop(); audioRecord.stop(); } catch (Throwable t) { Toast.makeText(testRecord.this, t.getMessage(), 1000); } } }; }

Android提高第十篇之AudioRecord實現"助聽器"