책보고 따라해서 만든 기본예제인데,,, 빌드는 성공적으로 됐는데, 앱을 실행한 후 녹음 버튼 누르기만 하면 앱이 바로 중지되네요;;;

무엇이 문제일까요?;

   아래는 코드 입니다. ㅠ 고수님들 도움이 필요합니당...

   package com.example.e.hello;

import android.content.ContentValues;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.appindexing.Thing;
import com.google.android.gms.common.api.GoogleApiClient;

public class MainActivity extends AppCompatActivity{
final private static String RECORDED_FILE = "/storage/emulated/0/VoIceRecorder/recorded.mp4"; //녹음된 음성을 저장할 파일 위치 정의

 private Button recordBtn;
private Button recordStopBtn;
private Button playBtn;
private Button playStopBtn;

private MediaPlayer player;         //음성 재생을 위한 MediaPlayer 변수 선언
 private MediaRecorder recorder =null;     //음성 녹음을 위한 MediaRecorder 변수 선언

 private GoogleApiClient client;

@Override
 protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

recordBtn=(Button)findViewById(R.id.recordBtn);
recordStopBtn=(Button)findViewById(R.id.recordStopBtn);
playBtn=(Button)findViewById(R.id.button3);
playStopBtn=(Button)findViewById(R.id.button4);



recordBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (recorder != null) {
recorder.stop();
recorder.release();
recorder = null;
                                             }
recorder = new MediaRecorder();             //MediaRecorder 객체 생성

 recorder.setAudioSource(MediaRecorder.AudioSource.MIC);         //MediaRecorder 객체에 필요한 정보 설명
 recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT);
recorder.setOutputFile(RECORDED_FILE);

try {
recorder.prepare();
recorder.start();
                                             } catch (Exception ex) {
                                                 Log.e("SampleAudioRecorder", "Exception : ", ex);          //prepare()와 start() 메소드를 이용해 녹음 시작
 }

                                         }

                                     }
        );

playBtn.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){

                System.out.println("HI/W");
            }
        });
recordStopBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (recorder == null)
return;

recorder.stop();            //녹음을 중지/리소스 해제
 recorder.release();
recorder = null;

                ContentValues values = new ContentValues(10);

                values.put(MediaStore.MediaColumns.TITLE, "Recorded");
                values.put(MediaStore.Audio.Media.ALBUM, "Audio Album");
                values.put(MediaStore.Audio.Media.ARTIST, "Mike");
                values.put(MediaStore.Audio.Media.DISPLAY_NAME, "Recorded Audio");
                values.put(MediaStore.Audio.Media.IS_RINGTONE, 1);
                values.put(MediaStore.Audio.Media.IS_MUSIC, 1);
                values.put(MediaStore.Audio.Media.DATE_ADDED, System.currentTimeMillis()/ 1000);
                values.put(MediaStore.MediaColumns.MIME_TYPE,"audio/mp4");
                values.put(MediaStore.Audio.Media.DATA, RECORDED_FILE);

                Uri audioUri = getContentResolver().insert(         //녹음 목록에 저장
 MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,values);
if(audioUri==null) {
                    Log.d("SampleAudioRecorder", "Audio insert failed.");
return;
                }}
        });






// ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
 client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();

    }

protected void onPause() {
if (recorder != null) {
recorder.release();
recorder = null;
        }

super.onPause();
    }
protected void onResume() {
super.onResume();
recorder = new MediaRecorder();

    }

 public Action getIndexApiAction() {
        Thing object = new Thing.Builder()
                .setName("Main Page") // TODO: Define a title for the content shown.
 // TODO: Make sure this auto-generated URL is correct.
 .setUrl(Uri.parse("http://[ENTER-YOUR-URL-HERE]"))
                .build();
return new Action.Builder(Action.TYPE_VIEW)
                .setObject(object)
                .setActionStatus(Action.STATUS_TYPE_COMPLETED)
                .build();
    }

@Override
 public void onStart() {
super.onStart();

// ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
 client.connect();
        AppIndex.AppIndexApi.start(client, getIndexApiAction());
    }

@Override
 public void onStop() {
super.onStop();

// ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
 AppIndex.AppIndexApi.end(client, getIndexApiAction());
client.disconnect();
    }
}