[ Android Audio ] 讀取 MIC 的音量

專案功能：能經由麥克風(MIC)讀取音量，並將數值顯示在TextView上

1. 新增專案
Project Name: voiceTest
Package Name: com.example.voicetest
Activity Name: MainActivity
SDK API: 15

2. 在TextView 新增 id

android:id="@+id/text1"

完整的main.xml如下：

3. 使用MediaRecorder來記錄聲音，並利用Handler來定時讀取音量的資訊，MainActivity.java完整程式列表。


package com.example.voicetest;

import java.io.IOException;

import android.media.AudioManager;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.support.v4.app.NavUtils;

public class MainActivity extends Activity {
private MediaRecorder mRecorder = null;
Handler handler = new Handler(){

@Override
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
super.handleMessage(msg);
double ringerVol = mRecorder.getMaxAmplitude();
       TextView tv = (TextView) findViewById(R.id.text1);
       tv.setText(Double.toString(ringerVol));
handler.sendMessageDelayed(Message.obtain(), 300);
}

};
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
if (mRecorder == null) {
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
   mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
   mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
   mRecorder.setOutputFile("/dev/null"); 
   try {
mRecorder.prepare();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
   mRecorder.start();
}
        handler.sendEmptyMessageDelayed(0, 1000);
    }

    @Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
if (mRecorder != null) {
mRecorder.stop();
mRecorder.release();
mRecorder = null;
}
}

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

 
}

4.新增權限

 5. 執行結果