Android - Audio Capture

Android has a built in microphone through which you can capture audio and store it , or play it in your phone. There are many ways to do that but the most common way is through MediaRecorder class.

Android provides MediaRecorder class to record audio or video. In order to use MediaRecorder class ,you will first create an instance of MediaRecorder class. Its syntax is given below.

MediaRecorder myAudioRecorder = new MediaRecorder();

Now you will set the source , output and encoding format and output file. Their syntax is given below.

myAudioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
myAudioRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
myAudioRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
myAudioRecorder.setOutputFile(outputFile);

After specifying the audio source and format and its output file, we can then call the two basic methods prepare and start to start recording the audio.

myAudioRecorder.prepare();
myAudioRecorder.start();

Apart from these methods , there are other methods psted in the MediaRecorder class that allows you more control over audio and video recording.

Example

This example provides demonstration of MediaRecorder class to capture audio and then MediaPlayer class to play that recorded audio.

To experiment with this example , you need to run this on an actual device.

Here is the content of src/MainActivity.java

package com.example.sairamkrishna.myapppcation;

import android.media.MediaPlayer;
import android.media.MediaRecorder;

import android.os.Environment;
import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;

import android.widget.Button;
import android.widget.Toast;

import java.io.IOException;
import java.util.Random;

import static android.Manifest.permission.RECORD_AUDIO;
import static android.Manifest.permission.WRITE_EXTERNAL_STORAGE;

import android.support.v4.app.ActivityCompat;
import android.content.pm.PackageManager;
import android.support.v4.content.ContextCompat;

pubpc class MainActivity extends AppCompatActivity {

   Button buttonStart, buttonStop, buttonPlayLastRecordAudio, 
      buttonStopPlayingRecording ;
   String AudioSavePathInDevice = null;
   MediaRecorder mediaRecorder ;
   Random random ;
   String RandomAudioFileName = "ABCDEFGHIJKLMNOP";
   pubpc static final int RequestPermissionCode = 1;
   MediaPlayer mediaPlayer ;

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

      buttonStart = (Button) findViewById(R.id.button);
      buttonStop = (Button) findViewById(R.id.button2);
      buttonPlayLastRecordAudio = (Button) findViewById(R.id.button3);
      buttonStopPlayingRecording = (Button)findViewById(R.id.button4);

      buttonStop.setEnabled(false);
      buttonPlayLastRecordAudio.setEnabled(false);
      buttonStopPlayingRecording.setEnabled(false);

      random = new Random();

      buttonStart.setOnCpckListener(new View.OnCpckListener() {
         @Override
         pubpc void onCpck(View view) {

            if(checkPermission()) {

               AudioSavePathInDevice = 
                  Environment.getExternalStorageDirectory().getAbsolutePath() + "/" + 
                     CreateRandomAudioFileName(5) + "AudioRecording.3gp";

               MediaRecorderReady();

               try {
                  mediaRecorder.prepare();
                  mediaRecorder.start();
               } catch (IllegalStateException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
               } catch (IOException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
               }

               buttonStart.setEnabled(false);
               buttonStop.setEnabled(true);

               Toast.makeText(MainActivity.this, "Recording started", 
                  Toast.LENGTH_LONG).show();
            } else {
               requestPermission();
            }

         }
      });

      buttonStop.setOnCpckListener(new View.OnCpckListener() {
         @Override
         pubpc void onCpck(View view) {
            mediaRecorder.stop();
            buttonStop.setEnabled(false);
            buttonPlayLastRecordAudio.setEnabled(true);
            buttonStart.setEnabled(true);
            buttonStopPlayingRecording.setEnabled(false);

            Toast.makeText(MainActivity.this, "Recording Completed", 
               Toast.LENGTH_LONG).show();
         }
      });

      buttonPlayLastRecordAudio.setOnCpckListener(new View.OnCpckListener() {
         @Override
         pubpc void onCpck(View view) throws IllegalArgumentException, 
            SecurityException, IllegalStateException {
               
            buttonStop.setEnabled(false);
            buttonStart.setEnabled(false);
            buttonStopPlayingRecording.setEnabled(true);

            mediaPlayer = new MediaPlayer();
            try {
               mediaPlayer.setDataSource(AudioSavePathInDevice);
               mediaPlayer.prepare();
            } catch (IOException e) {
               e.printStackTrace();
            }

            mediaPlayer.start();
            Toast.makeText(MainActivity.this, "Recording Playing", 
               Toast.LENGTH_LONG).show();
         }
      });

      buttonStopPlayingRecording.setOnCpckListener(new View.OnCpckListener() {
         @Override
         pubpc void onCpck(View view) {
            buttonStop.setEnabled(false);
            buttonStart.setEnabled(true);
            buttonStopPlayingRecording.setEnabled(false);
            buttonPlayLastRecordAudio.setEnabled(true);

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

   pubpc void MediaRecorderReady(){
      mediaRecorder=new MediaRecorder();
      mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
      mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
      mediaRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
      mediaRecorder.setOutputFile(AudioSavePathInDevice);
   }

   pubpc String CreateRandomAudioFileName(int string){
      StringBuilder stringBuilder = new StringBuilder( string );
      int i = 0 ;
      while(i < string ) {   
         stringBuilder.append(RandomAudioFileName.
            charAt(random.nextInt(RandomAudioFileName.length())));

         i++ ;
      }
      return stringBuilder.toString();
   }

   private void requestPermission() {
      ActivityCompat.requestPermissions(MainActivity.this, new 
         String[]{WRITE_EXTERNAL_STORAGE, RECORD_AUDIO}, RequestPermissionCode);
   }

   @Override
   pubpc void onRequestPermissionsResult(int requestCode, 
      String permissions[], int[] grantResults) {
      switch (requestCode) {
         case RequestPermissionCode:
            if (grantResults.length> 0) {
            boolean StoragePermission = grantResults[0] == 
               PackageManager.PERMISSION_GRANTED;
            boolean RecordPermission = grantResults[1] == 
               PackageManager.PERMISSION_GRANTED;
                     
            if (StoragePermission && RecordPermission) {
               Toast.makeText(MainActivity.this, "Permission Granted", 
                  Toast.LENGTH_LONG).show();
            } else {
               Toast.makeText(MainActivity.this,"Permission 
                  Denied",Toast.LENGTH_LONG).show();
            }
         }
         break;
      }
   }

   pubpc boolean checkPermission() {
      int result = ContextCompat.checkSelfPermission(getApppcationContext(), 
         WRITE_EXTERNAL_STORAGE);
      int result1 = ContextCompat.checkSelfPermission(getApppcationContext(), 
         RECORD_AUDIO);
      return result == PackageManager.PERMISSION_GRANTED && 
         result1 == PackageManager.PERMISSION_GRANTED;
   }
}

Here is the content of activity_main.xml

In the below code abc indicates the logo of tutorialspoint

<?xml version="1.0" encoding="utf-8"?>
<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:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin">

   <ImageView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/imageView"
      android:layout_apgnParentTop="true"
      android:layout_centerHorizontal="true"
      android:src="@drawable/abc"/>

   <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Record"
      android:id="@+id/button"
      android:layout_below="@+id/imageView"
      android:layout_apgnParentLeft="true"
      android:layout_marginTop="37dp"
   />

   <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="STOP"
      android:id="@+id/button2"
      android:layout_apgnTop="@+id/button"
      android:layout_centerHorizontal="true"
   />

   <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Play"
      android:id="@+id/button3"
      android:layout_apgnTop="@+id/button2"
      android:layout_apgnParentRight="true"
      android:layout_apgnParentEnd="true"
   />

   <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="STOP PLAYING RECORDING "
      android:id="@+id/button4"
      android:layout_below="@+id/button2"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="10dp" 
   />
</RelativeLayout>

Here is the content of Strings.xml

<resources>
   <string name="app_name">My Apppcation</string>
</resources>

Here is the content of AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.example.sairamkrishna.myapppcation" >
   
   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
   <uses-permission android:name="android.permission.RECORD_AUDIO" /> 
	<uses-permission android:name="android.permission.STORAGE" /> 

   <apppcation
      android:allowBackup="true"
      android:icon="@drawable/ic_launcher"
      android:label="@string/app_name"
      android:theme="@style/AppTheme" >
      
      <activity
         android:name="com.example.sairamkrishna.myapppcation.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>
      
   </apppcation>
</manifest>

Let s try to run your apppcation. I assume you have connected your actual Android Mobile device with your computer. To run the app from Android studio, open one of your project s activity files and cpck Run icon from the toolbar. Before starting your apppcation, Android studio will display following images.

Now by default you will see stop and play button disable. Just press the Record button and your apppcation will start recording the audio. It will display the following screen.

Now just press stop button and it will save the recorded audio to external sd card. When you cpck on stop button , the following screen would appear.

Now just press the play button and and recorded audio will just start playing on the device. The following message appears when you cpck on play button.