Android提高第十篇之AudioRecord实现"助听器"

本文来自http://blog.youkuaiyun.com/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：

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

main.xml的源码如下：

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1. <?xmlversion="1.0"encoding="utf-8"?>
2. <LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
3. android:orientation="vertical"android:layout_width="fill_parent"
4. android:layout_height="fill_parent">
6. <Buttonandroid:layout_height="wrap_content"android:id="@+id/btnRecord"
7. android:layout_width="fill_parent"android:text="开始边录边放"></Button>
8. <Buttonandroid:layout_height="wrap_content"
9. android:layout_width="fill_parent"android:text="停止"android:id="@+id/btnStop"></Button>
10. <Buttonandroid:layout_height="wrap_content"android:id="@+id/btnExit"
11. android:layout_width="fill_parent"android:text="退出"></Button>
12. <TextViewandroid:id="@+id/TextView01"android:layout_height="wrap_content"
13. android:text="程序音量调节"android:layout_width="fill_parent"></TextView>
14. <SeekBarandroid:layout_height="wrap_content"android:id="@+id/skbVolume"
15. android:layout_width="fill_parent"></SeekBar>
17. </LinearLayout>

testRecord.java的源码如下：

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1. packagecom.testRecord;
3. importandroid.app.Activity;
4. importandroid.media.AudioFormat;
5. importandroid.media.AudioManager;
6. importandroid.media.AudioRecord;
7. importandroid.media.AudioTrack;
8. importandroid.media.MediaRecorder;
9. importandroid.os.Bundle;
10. importandroid.view.View;
11. importandroid.widget.Button;
12. importandroid.widget.SeekBar;
13. importandroid.widget.Toast;
15. publicclasstestRecordextendsActivity{
16. /**Calledwhentheactivityisfirstcreated.*/
17. ButtonbtnRecord,btnStop,btnExit;
18. SeekBarskbVolume;//调节音量
19. booleanisRecording=false;//是否录放的标记
20. staticfinalintfrequency=44100;
21. staticfinalintchannelConfiguration=AudioFormat.CHANNEL_CONFIGURATION_MONO;
22. staticfinalintaudioEncoding=AudioFormat.ENCODING_PCM_16BIT;
23. intrecBufSize,playBufSize;
24. AudioRecordaudioRecord;
25. AudioTrackaudioTrack;
27. @Override
28. publicvoidonCreate(BundlesavedInstanceState){
29. super.onCreate(savedInstanceState);
30. setContentView(R.layout.main);
31. setTitle("助听器");
32. recBufSize=AudioRecord.getMinBufferSize(frequency,
33. channelConfiguration,audioEncoding);
35. playBufSize=AudioTrack.getMinBufferSize(frequency,
36. channelConfiguration,audioEncoding);
37. //-----------------------------------------
38. audioRecord=newAudioRecord(MediaRecorder.AudioSource.MIC,frequency,
39. channelConfiguration,audioEncoding,recBufSize);
41. audioTrack=newAudioTrack(AudioManager.STREAM_MUSIC,frequency,
42. channelConfiguration,audioEncoding,
43. playBufSize,AudioTrack.MODE_STREAM);
44. //------------------------------------------
45. btnRecord=(Button)this.findViewById(R.id.btnRecord);
46. btnRecord.setOnClickListener(newClickEvent());
47. btnStop=(Button)this.findViewById(R.id.btnStop);
48. btnStop.setOnClickListener(newClickEvent());
49. btnExit=(Button)this.findViewById(R.id.btnExit);
50. btnExit.setOnClickListener(newClickEvent());
51. skbVolume=(SeekBar)this.findViewById(R.id.skbVolume);
52. skbVolume.setMax(100);//音量调节的极限
53. skbVolume.setProgress(70);//设置seekbar的位置值
54. audioTrack.setStereoVolume(0.7f,0.7f);//设置当前音量大小
55. skbVolume.setOnSeekBarChangeListener(newSeekBar.OnSeekBarChangeListener(){
57. @Override
58. publicvoidonStopTrackingTouch(SeekBarseekBar){
59. floatvol=(float)(seekBar.getProgress())/(float)(seekBar.getMax());
60. audioTrack.setStereoVolume(vol,vol);//设置音量
61. }
63. @Override
64. publicvoidonStartTrackingTouch(SeekBarseekBar){
65. //TODOAuto-generatedmethodstub
66. }
68. @Override
69. publicvoidonProgressChanged(SeekBarseekBar,intprogress,
70. booleanfromUser){
71. //TODOAuto-generatedmethodstub
72. }
73. });
74. }
76. @Override
77. protectedvoidonDestroy(){
78. super.onDestroy();
79. android.os.Process.killProcess(android.os.Process.myPid());
80. }
82. classClickEventimplementsView.OnClickListener{
84. @Override
85. publicvoidonClick(Viewv){
86. if(v==btnRecord){
87. isRecording=true;
88. newRecordPlayThread().start();//开一条线程边录边放
89. }elseif(v==btnStop){
90. isRecording=false;
91. }elseif(v==btnExit){
92. isRecording=false;
93. testRecord.this.finish();
94. }
95. }
96. }
98. classRecordPlayThreadextendsThread{
99. publicvoidrun(){
100. try{
101. byte[]buffer=newbyte[recBufSize];
102. audioRecord.startRecording();//开始录制
103. audioTrack.play();//开始播放
105. while(isRecording){
106. //从MIC保存数据到缓冲区
107. intbufferReadResult=audioRecord.read(buffer,0,
108. recBufSize);
110. byte[]tmpBuf=newbyte[bufferReadResult];
111. System.arraycopy(buffer,0,tmpBuf,0,bufferReadResult);
112. //写入数据即播放
113. audioTrack.write(tmpBuf,0,tmpBuf.length);
114. }
115. audioTrack.stop();
116. audioRecord.stop();
117. }catch(Throwablet){
118. Toast.makeText(testRecord.this,t.getMessage(),1000);
119. }
120. }
121. };
122. }