MediaRecorder と MediaPlayer を使用して再生オーディオを録音できるアプリに取り組んでいます。maxAmplitude の値も表示したいと思います。getMaxAmplitude を使用しようとしましたが、機能しません。0を返し続けます。レコーダーとプレーヤーは正常に動作しています（developer.android.comからのものです）。誰かが私を助けてくれませんか。最終的にはdBを表示したいのですが、これが機能したら自分でできると思います。私はAndroid/Javaが初めてなので、どんな助けも大歓迎です。
私のコード
public class AudioRecordTest extends Activity{
private static final String LOG_TAG = "AudioRecordTest";
protected static final String TAG = null;
private static String mFileName = null;
private RecordButton mRecordButton = null;
private MediaRecorder mRecorder = null;
private PlayButton mPlayButton = null;
private MediaPlayer mPlayer = null;
private int currentAmplitude;
public boolean activeThread;
private void onRecord(boolean start) {
if (start) {
startRecording();
} else {
stopRecording();
}
}
private void onPlay(boolean start) {
if (start) {
startPlaying();
} else {
stopPlaying();
}
}
private void startPlaying() {
mPlayer = new MediaPlayer();
try {
mPlayer.setDataSource(mFileName);
mPlayer.prepare();
mPlayer.start();
} catch (IOException e) {
Log.e(LOG_TAG, "prepare() failed");
}
}
private void stopPlaying() {
mPlayer.release();
mPlayer = null;
}
private void startRecording() {
if (mRecorder == null) {
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setOutputFile(mFileName);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
}
try {
mRecorder.prepare();
} catch (IOException e) {
Log.e(LOG_TAG, "prepare() failed");
}
mRecorder.start();
}
private void stopRecording() {
mRecorder.stop();
mRecorder.release();
activeThread = true;
mRecorder = null;
}
public void run() {
// TODO Auto-generated method stub
try {
activeThread = true;
while(activeThread){
Log.i(TAG, "onRun()" );
Thread.sleep(50);
threadHandler.sendEmptyMessage(0);
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private Handler threadHandler = new Handler() {
public void handleMessage(android.os.Message msg) {
currentAmplitude = mRecorder.getMaxAmplitude();
Log.i(TAG, "handleMessage : MaxAmplitude : "+Integer.toString(currentAmplitude) );
}
};
class RecordButton extends Button {
boolean mStartRecording = true;
OnClickListener clicker = new OnClickListener() {
public void onClick(View v) {
onRecord(mStartRecording);
if (mStartRecording) {
setText("Stop recording");
} else {
setText("Start recording");
}
mStartRecording = !mStartRecording;
}
};
public RecordButton(Context ctx) {
super(ctx);
setText("Start recording");
setOnClickListener(clicker);
}
}
class PlayButton extends Button {
boolean mStartPlaying = true;
OnClickListener clicker = new OnClickListener() {
public void onClick(View v) {
onPlay(mStartPlaying);
if (mStartPlaying) {
setText("Stop playing");
} else {
setText("Start playing");
}
mStartPlaying = !mStartPlaying;
}
};
public PlayButton(Context ctx) {
super(ctx);
setText("Start playing");
setOnClickListener(clicker);
}
}
public AudioRecordTest() {
mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
mFileName += "/audiorecordtest.3gp";
}
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
LinearLayout ll = new LinearLayout(this);
mRecordButton = new RecordButton(this);
ll.addView(mRecordButton,
new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT,
0));
mPlayButton = new PlayButton(this);
ll.addView(mPlayButton,
new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT,
0));
TextView tv = new TextView(this);
ll.addView(tv,
new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT,
0));
tv.setText(Integer.toString(currentAmplitude));
setContentView(ll);
}
@Override
public void onPause() {
super.onPause();
if (mRecorder != null) {
mRecorder.release();
mRecorder = null;
}
if (mPlayer != null) {
mPlayer.release();
mPlayer = null;
}
}
}