Android Studio - Saving audios

I would like to know how I can save various audio and then access it, and my program is closing every time I record the first audio.

Code:

package com.example.pedri.audiorecod;

import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.os.Environment;
import android.provider.MediaStore;
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;

public class MainActivity extends AppCompatActivity {

    private Button play, stop, record; //variáveis de instância
    private MediaRecorder myAudioRecorder;//variáveis de instância
    private String outputFile;//variáveis de instância
/*Declando as variáveis de instância, pois assim todos os métodos da Classe  MainActivity extends AppCompatActivity
pode manipular a variávels de instância
  */

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        play = (Button) findViewById(R.id.play);
        stop = (Button) findViewById(R.id.stop);
        record = (Button) findViewById(R.id.recod);
        stop.setEnabled(false);
        play.setEnabled(false);


        outputFile = Environment.getExternalStorageDirectory().getAbsolutePath() + "/recording.3gp";

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



        record.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    myAudioRecorder.prepare();
                    myAudioRecorder.start();
                } catch (IllegalStateException ise) {
                } catch (IOException ioe) {
                }
                record.setEnabled(false);
                stop.setEnabled(true);

                Toast.makeText(getApplicationContext(), "Gravação Iniciada", Toast.LENGTH_LONG).show();

            }
        });
        stop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                myAudioRecorder.stop();
                myAudioRecorder.release();
                myAudioRecorder = null;
                record.setEnabled(true);
                stop.setEnabled(false);
                play.setEnabled(true);
                Toast.makeText(getApplicationContext(), "Áudio Gravado com Sucesso", Toast.LENGTH_LONG).show();
            }
        });

        play.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                MediaPlayer mediaPlayer = new MediaPlayer();

                try{
                    mediaPlayer.setDataSource(outputFile);
                    mediaPlayer.prepare();
                    mediaPlayer.start();

                    Toast.makeText(getApplicationContext(), "Comece o Áudio", Toast.LENGTH_LONG).show();

                } catch (IOException e) {

                }
            }
        });

    }
}