Android Audio Recording Tutorial

After many hours of trying to record audio on my Google Android device, I’ve finally arrived at a workable solution. There were a few bumps along the way besides the horribly out of date MediaRecorder documentation, which was sorely lacking details. For one, I could only get audio to record to the SD card. Additionally, the directory being recorded to must already exist before attempting to record to it. Without further ado, here is a complete example for recording audio on the Android via the MediaRecorder API:

package com.benmccann.android.hello;

import java.io.File;

import java.io.IOException;

import android.media.MediaRecorder;

import android.os.Environment;

/**

* @author Ben McCann

*/

public class AudioRecorder {

final MediaRecorder recorder = new MediaRecorder();

final String path;

/**

* Creates a new audio recording at the given path (relative to root of SD card).

*/

public AudioRecorder(String path) {

this.path = sanitizePath(path);

}

private String sanitizePath(String path) {

if (!path.startsWith(“/”)) {

path = “/” + path;

}

if (!path.contains(“.”)) {

path += “.3gp”;

}

return Environment.getExternalStorageDirectory().getAbsolutePath() + path;

}

/**

* Starts a new recording.

*/

public void start() throws IOException {

String state = android.os.Environment.getExternalStorageState();

if(!state.equals(android.os.Environment.MEDIA_MOUNTED)) {

throw new IOException(“SD Card is not mounted. It is ” + state + “.”);

}

// make sure the directory we plan to store the recording in exists

File directory = new File(path).getParentFile();

if (!directory.exists() && !directory.mkdirs()) {

throw new IOException(“Path to file could not be created.”);

}

recorder.setAudioSource(MediaRecorder.AudioSource.MIC);

recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);

recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

recorder.setOutputFile(path);

recorder.prepare();

recorder.start();

}

/**

* Stops a recording that has been previously started.

*/

public void stop() throws IOException {

recorder.stop();

recorder.release();

}

}