I am trying to record audio by MediaRecorder, and I get an error, I tried to change everything and nothing works. Last two hours I try to find the error, I used Log class too and I found out that error occurred when it call recorder.start() method. What could be the problem?

public class AudioRecorderActivity extends Activity {

MediaRecorder recorder;
File audioFile = null;
private static final String TAG = "AudioRecorderActivity";
private View startButton;
private View stopButton;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    startButton = findViewById(R.id.start);
    stopButton = findViewById(R.id.stop);

    setContentView(R.layout.main);
}

public void startRecording(View view) throws IOException{

    startButton.setEnabled(false);
    stopButton.setEnabled(true);

    File sampleDir = Environment.getExternalStorageDirectory();

    try{
        audioFile = File.createTempFile("sound", ".3gp", sampleDir);
    }catch(IOException e){
        Toast.makeText(getApplicationContext(), "SD Card Access Error", Toast.LENGTH_LONG).show();
        Log.e(TAG, "Sdcard access error");
        return;
    }

    recorder = new MediaRecorder();
    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
    recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    recorder.setAudioEncodingBitRate(16);
    recorder.setAudioSamplingRate(44100);
    recorder.setOutputFile(audioFile.getAbsolutePath());
    recorder.prepare();
    recorder.start();
}

public void stopRecording(View view){
    startButton.setEnabled(true);
    stopButton.setEnabled(false);
    recorder.stop();
    recorder.release();
    addRecordingToMediaLibrary();
}

protected void addRecordingToMediaLibrary(){
    ContentValues values = new ContentValues(4);
    long current = System.currentTimeMillis();
    values.put(MediaStore.Audio.Media.TITLE, "audio" + audioFile.getName());
    values.put(MediaStore.Audio.Media.DATE_ADDED, (int)(current/1000));
    values.put(MediaStore.Audio.Media.MIME_TYPE, "audio/3gpp");
    values.put(MediaStore.Audio.Media.DATA, audioFile.getAbsolutePath());
    ContentResolver contentResolver = getContentResolver();

    Uri base = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Uri newUri = contentResolver.insert(base, values);

    sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, newUri));
    Toast.makeText(this, "Added File" + newUri, Toast.LENGTH_LONG).show();
    }

} 

And here is the xml layout.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/RelativeLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<Button
    android:id="@+id/start"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="146dp"
    android:onClick="startRecording"
    android:text="Start Recording" />

<Button
    android:id="@+id/stop"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/start"
    android:layout_below="@+id/start"
    android:layout_marginTop="41dp"
    android:enabled="false"
    android:onClick="stopRecording"
    android:text="Stop Recording" />

 </RelativeLayout>

And I added permission to AndroidManifest file.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="in.isuru.audiorecorder"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk android:minSdkVersion="8" />


<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name" >
    <activity
        android:name=".AudioRecorderActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

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

</manifest>

I need to record high quality audio.

Thanks!