メディアレコーダーが停止するとクラッシュする

Question

マイクから音声を録音するボイスチャットアプリケーションを作成しています。録音を開始するとうまく始まりますが、録音を停止すると、録音が​​停止して2回目にクラッシュし、音を録音して停止し、外部記憶装置にオーディオファイルを作成します最初の問題です。

ChatActivity.java

package com.example.usamaakmal.npproject; 

import android.graphics.Color; 
import android.media.MediaPlayer; 
import android.media.MediaRecorder; 
import android.os.Build; 
import android.os.Environment; 
import android.support.annotation.NonNull; 
import android.support.annotation.RequiresApi; 
import android.support.design.widget.BottomNavigationView; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.MenuItem; 
import android.view.MotionEvent; 
import android.view.View; 
import android.widget.Button; 
import android.widget.CompoundButton; 
import android.widget.Toast; 
import android.widget.ToggleButton; 

import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.nio.ByteBuffer; 
import java.nio.channels.FileChannel; 
import java.time.LocalDateTime; 
import java.util.Timer; 

public class ChatActivity extends AppCompatActivity { 

    ToggleButton recButton; 
    MediaRecorder recorder = null; 
    boolean recoredAlreadClicked = false; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_chat); 
     this.setTitle("Chat Room"); 

     File dir = new File(Environment.getExternalStorageDirectory()+"/NPProject"); 
     if (!dir.isDirectory()){ 
      dir.mkdir(); 
     } else { 
      deleteDir(dir); 
     } 
     BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation); 
     navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener); 

    } 
    private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener 
      = new BottomNavigationView.OnNavigationItemSelectedListener() { 

     @RequiresApi(api = Build.VERSION_CODES.O) 
     @Override 
     public boolean onNavigationItemSelected(@NonNull MenuItem item) { 
      switch (item.getItemId()) { 
       case R.id.send: 

        return true; 
       case R.id.play: 
        playRecording(); 
        return true; 
       case R.id.record: 
        if (recoredAlreadClicked){ 
         item.setIcon(R.drawable.ic_mic_black_24dp); 
         item.setTitle("Record"); 
         Toast.makeText(ChatActivity.this, "Stopping Recording", Toast.LENGTH_SHORT).show(); 
         try { 
          stopRec(); 
         } catch (IOException e) { 
          e.printStackTrace(); 
         } 
         recoredAlreadClicked = !recoredAlreadClicked; 
         return false; 
        }else{ 
         item.setIcon(R.drawable.ic_home_black_24dp); 
         item.setTitle("Stop"); 
         Toast.makeText(ChatActivity.this, "Starting Recording", Toast.LENGTH_SHORT).show(); 
         startRec(); 
         recoredAlreadClicked = !recoredAlreadClicked; 
         return true; 
        } 
      } 
      return false; 
     } 
    }; 


    public static boolean deleteDir(File dir) { 
     if (dir.isDirectory()) { 
      String[] children = dir.list(); 
      for (int i=0; i<children.length; i++) { 
       boolean success = deleteDir(new File(dir, children[i])); 
       if (!success) { 
        return false; 
       } 
      } 
     } 

     return dir.delete(); 
    } 

    public void playRecording() { 
     MediaPlayer mediaPlayer = new MediaPlayer(); 
     try { 
      mediaPlayer.setDataSource(Environment.getExternalStorageDirectory()+"/NPProject/audio.m4a"); 
      mediaPlayer.prepare(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
     mediaPlayer.start(); 
    } 


    private void startRec() { 
     Toast.makeText(this, "Test", Toast.LENGTH_SHORT).show(); 
     if (recorder != null) { 
      recorder.release(); 
     } 
     recorder = new MediaRecorder(); 
     recorder.setAudioSource(MediaRecorder.AudioSource.MIC); 
     recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4); 
     recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_WB); 
     recorder.setOutputFile(Environment.getExternalStorageDirectory()+"/NPProject/"+ SocketHelper.getName() +"-"+System.currentTimeMillis()+".m4a"); 
     try { 
      recorder.prepare(); 
      recorder.start(); 
     } catch (IOException e) { 
      Log.e("giftlist", "io problems while preparing [" + 
        getFilesDir() + "]: " + e.getMessage()); 
     } 
    } 

    private void stopRec() throws IOException { 
     if (recorder != null) { 
      recorder.stop(); 
      recorder.release(); 
      recorder = null; 
     } 

     // Toast.makeText(ChatActivity.this, ""+convertAudioToByte().length, Toast.LENGTH_SHORT).show(); 
    } 

    public byte[] convertAudioToByte() throws IOException { 
     FileInputStream inputStream = new FileInputStream(Environment.getExternalStorageDirectory()+"/NPProject/audio.m4a"); 
     FileChannel fc = inputStream.getChannel(); 
     ByteBuffer buffer = ByteBuffer.allocate((int)fc.size()); 
     fc.read(buffer); 
     return buffer.array(); 
    } 

    public void convertByteToAudio(byte[] b) throws IOException { 
     FileOutputStream outputStream = new FileOutputStream(Environment.getExternalStorageDirectory()+ "/NPProject/audio.m4a"); 
     outputStream.write(b); 
     outputStream.flush(); 
     outputStream.close(); 
    } 
} 

これは、アプリは

E/MediaRecorder: stop called in an invalid state: 4 
E/AndroidRuntime: FATAL EXCEPTION: main 
        Process: com.example.usamaakmal.npproject, PID: 12556 
        java.lang.IllegalStateException 
         at android.media.MediaRecorder.native_stop(Native Method) 
         at android.media.MediaRecorder.stop(MediaRecorder.java:1244) 
         at com.example.usamaakmal.npproject.ChatActivity.stopRec(ChatActivity.java:138) 
         at com.example.usamaakmal.npproject.ChatActivity.access$000(ChatActivity.java:31) 
         at com.example.usamaakmal.npproject.ChatActivity$1.onNavigationItemSelected(ChatActivity.java:71) 
         at android.support.design.widget.BottomNavigationView$1.onMenuItemSelected(BottomNavigationView.java:182) 
         at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:822) 
         at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:171) 
         at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:973) 
         at android.support.design.internal.BottomNavigationMenuView$1.onClick(BottomNavigationMenuView.java:95) 
         at android.view.View.performClick(View.java:5646) 
         at android.view.View$PerformClick.run(View.java:22459) 
         at android.os.Handler.handleCallback(Handler.java:761) 
         at android.os.Handler.dispatchMessage(Handler.java:98) 
         at android.os.Looper.loop(Looper.java:156) 
         at android.app.ActivityThread.main(ActivityThread.java:6523) 
         at java.lang.reflect.Method.invoke(Native Method) 
         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:942) 
         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:832) 

Answer 1

を墜落したとき、私は私が許可申請を与えることによって、この問題を解決し得たもの活動のスタックトレースですの設定でマイクを録音するには、実行時の権限を追加していないので、これが問題です。