Android提高第十篇之AudioRecord实现"助听器"

本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！

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);
			}
		}
	};
}