Android mMediaRecorder.stop() 报错， 你蛋疼了吗？

import java.io.File;
import java.io.IOException;

import android.content.Context;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.os.Environment;

public class Recorder {
MediaRecorder mMediaRecorder;
MediaPlayer mediaPlayer;
Context context;
File mRecAudioFile;
File mRecAudioPath;
String strTempFile = "recaudio_";
private static MediaRecorder m=null;
public Recorder(Context context) {
// TODO Auto-generated constructor stub
this.context = context;
mediaPlayer = new MediaPlayer();
}

private MediaRecorder getInstance(){
if (m==null) {
m=new MediaRecorder();
}
return m;
}

public void startRecord() {
try {
if (!initRecAudioPath()) {
return;
}

if (mMediaRecorder != null) {
return;
}

mMediaRecorder = getInstance();
mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);// …Ë÷√¬ÛøÀ∑Á
mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT);
mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT);
try {
mRecAudioFile = File.createTempFile(strTempFile, ".amr",
mRecAudioPath);

} catch (Exception e) {
e.printStackTrace();
}
mMediaRecorder.setOutputFile(mRecAudioFile.getAbsolutePath());
mMediaRecorder.prepare();
mMediaRecorder.start();
} catch (IOException e) {
e.printStackTrace();
}
}

public void stopRecord() {
if (mRecAudioFile != null && mMediaRecorder != null) {

try {
mMediaRecorder.setOnErrorListener(null);
mMediaRecorder.setPreviewDisplay(null);
mMediaRecorder.stop();
mMediaRecorder.release();
mMediaRecorder = null;
} catch (Exception e) {
// TODO: handle exception
}

}
}

public void playMusic() {
/*
* Intent intent = new Intent();
* intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
* intent.setAction(android.content.Intent.ACTION_VIEW);
* intent.setDataAndType(Uri.fromFile(mRecAudioFile), "audio");
* context.startActivity(intent);
*/

if (mMediaRecorder != null) {
return;
}

try {

mediaPlayer.reset();
mediaPlayer.setDataSource(mRecAudioFile.getAbsolutePath());
mediaPlayer.prepare();
mediaPlayer.start();
} catch (Exception e) {
// TODO: handle exception
}

}

private boolean initRecAudioPath() {
if (sdcardIsValid()) {
String path = Environment.getExternalStorageDirectory().toString()
+ File.separator + "record";// µ√µΩSDø®µ√¬∑æ∂
mRecAudioPath = new File(path);
if (!mRecAudioPath.exists()) {
mRecAudioPath.mkdirs();
}
} else {
mRecAudioPath = null;
}
return mRecAudioPath != null;
}

private boolean sdcardIsValid() {
if (Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED)) {
return true;
} else {
}
return false;
}

}