MediaRecorder not saving audio to file

Question

I'm trying out the Android audio capture example (https://developer.android.com/guide/topics/media/audio-capture.html) but it doesn't seem to work on Samsung Galaxy S5 (the only phone I've tested this on). This is using API level 23.

The audio file does get created on disk but it is a 0 byte file - which is clearly incorrect. This makes me believe something isn't correct with MediaRecorder.

Another side note, the MediaRecorder's getMaxAmplitude seems to be working - so it does have access to the microphone.

I found a bunch of other questions on SO but none of them have an answer. Has anyone been running into this lately?

Answer 1

I have post the full code with all the thing so you have no problem to do it.

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="68dp"
        android:layout_marginTop="50dp"
        android:text="Start Recording"
        />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button1"
        android:layout_below="@+id/button1"
        android:layout_marginTop="64dp"
        android:text="Stop Recording"
        />
</RelativeLayout>

MainActivity.java

public class MainActivity extends Activity implements View.OnClickListener{


    private Button startButton;
    private Button stopButton;
    private MediaRecorder mediaRecorder;
    private File audioFile;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        startButton = (Button) findViewById(R.id.button1);
        startButton.setOnClickListener(this);
        startButton.setText("start");

        stopButton = (Button) findViewById(R.id.button2);
        stopButton.setOnClickListener(this);
        stopButton.setEnabled(false);
        stopButton.setText("stop");

        audioFile = new File(Environment.getExternalStorageDirectory(),
                "audio_test4.3gp");

    }

    private void resetRecorder() {
        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        mediaRecorder.setAudioEncodingBitRate(16);
        mediaRecorder.setAudioSamplingRate(44100);
        mediaRecorder.setOutputFile(audioFile.getAbsolutePath());

        try {
            mediaRecorder.prepare();
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.button1:
                mediaRecorder = new MediaRecorder();
                resetRecorder();
                mediaRecorder.start();

                startButton.setEnabled(false);
                stopButton.setEnabled(true);
                break;
            case R.id.button2:
                try {
                    mediaRecorder.stop();
                }catch (RuntimeException ex){

                }
                mediaRecorder.release();
                mediaRecorder = null;

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

    @Override
    protected void onPause() {
        super.onPause();

        if (mediaRecorder != null) {
            mediaRecorder.stop();
            mediaRecorder.release();
            mediaRecorder = null;
        }
    }


}

manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.softeng.audiorecording" >

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            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>

</manifest>

ScreenShot form Android device Monitor :

In my java code see I have give it name audio_test4.3gp and In ScreenShot there is file with same name and it size is 3104.