10.AudioRecord实现“助听器”

Android可以利用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：

?

1

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

main.xml的源码如下：

?

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

<?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:id="@+id/btnRecord"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="开始边录边放"

        />

    <Button

        android:id="@+id/btnStop"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="停止"

        />

    <Button

        android:id="@+id/btnExit"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="退出"

        >

    <TextView

        android:id="@+id/TextView01"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="程序音量调节"

        />

    <SeekBar

        android:id="@+id/skbVolume"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        />

</LinearLayout>

testRecord.java的源码如下：

?

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

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(newSeekBar.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);

            }

        }

    };

}