Null pointer Исключение при использовании handler.obtainmessage

Question

Я использую обработчик для передачи значения переменной в поток пользовательского интерфейса в android. Однако приложение выходит из строя, как только оно достигает обработчика. Любая идея исправить будет большой помощью. Вот мой код:

String var = "NO Keyword Found"; 
         Message completeMessage = mHandler.obtainMessage(); 
         completeMessage.obj = var; 

         completeMessage.sendToTarget(); 

Заранее спасибо

Вот полный код threD:

import java.io.ByteArrayOutputStream; 
import java.io.File; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.util.ArrayList; 
import java.util.HashMap; 

import android.annotation.SuppressLint; 
import android.annotation.TargetApi; 
import android.app.Activity; 
import android.content.Context; 

import android.graphics.Bitmap; 
import android.media.MediaMetadataRetriever; 
import android.media.MediaPlayer; 
import android.net.Uri; 
import android.os.Build; 
import android.os.Bundle; 
import android.os.Environment; 
import android.os.Handler; 
import android.os.Message; 

import android.util.Log; 

public class FrameProcessor extends Thread { 
    private Uri uri = null; 
    private Handler mHandler = null; 
    private static volatile boolean bKeepRunning = true; 
    private String value = null; 
    private Context context = null; 

    public FrameProcessor(Object obj, Handler handler, Uri uri) { 
     if (obj != null) { 
      this.uri = uri; 
      this.mHandler = handler; 
     } 
     this.context = (Context) obj; 
    } 

    public void setIndex(String val) { 
     this.value = val; 
    } 

    @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH) 
    public void run() { 

     MediaMetadataRetriever retriever = new MediaMetadataRetriever(); 

     retriever.setDataSource(uri.toString(), new HashMap<String, String>()); 
     Log.v("FrameProcessor", "Video path set.... "); 
     ArrayList<Bitmap> rev = new ArrayList<Bitmap>(); 
     Log.v("FrameProcessor", "uri is: " + uri); 
     MediaPlayer mp = MediaPlayer.create(context, uri); 
     Log.v("FrameProcessor", "MP created "); 
     int millis = mp.getDuration(); 

     for (int i = 1000000; i < millis * 1000; i += 1000000) { 
      Log.v("FrameProcessor", "In Thread's for loop "); 
      Bitmap bitmap = retriever.getFrameAtTime(i, 
        MediaMetadataRetriever.OPTION_CLOSEST_SYNC); 
      rev.add(bitmap); 

      try { 
       saveFrames(rev); 
      } catch (IOException e) { 

       e.printStackTrace(); 
      } 
     } 

    } 

    @SuppressLint("ShowToast") 
    public void saveFrames(ArrayList<Bitmap> saveBitmapList) throws IOException { 
     Log.v("FrameProcessor", "In saveFrames "); 
     if (value != null) { 
      Log.v("FrameProcessor", value); 

      if (value.equals("0")) { 
       uri = Uri 
         .parse("http://html5dev.anorakstech.com/videos/video.mp4"); 
      } else if (value.equals("1")) { 
       uri = Uri 
         .parse("http://html5dev.anorakstech.com/videos/HSNvideo.mp4"); 
      } else if (value.equals("2")) { 
       uri = Uri 
         .parse("http://html5dev.anorakstech.com/videos/HSNMarkVideo.mp4"); 
      } 
      Log.v("FrameProcessor", uri.toString()); 
     } else { 

     } 
     if (value.equals("0")) { 
      String folder = Environment.getExternalStorageDirectory() 
        .toString(); 

      File saveFolder = new File(folder + "/Movies/Frames/"); 

      if (!saveFolder.exists()) { 
       saveFolder.mkdirs(); 

       Log.v("FrameProcessor", "Extracting Frames.... "); 

      } 

      int i = 1; 
      for (Bitmap b : saveBitmapList) { 
       Log.v("FrameProcessor", "In saveFrames for loop"); 
       ByteArrayOutputStream bytes = new ByteArrayOutputStream(); 
       b.compress(Bitmap.CompressFormat.JPEG, 40, bytes); 

       File f = new File(saveFolder, ("frame" + i + ".jpg")); 

       f.createNewFile(); 
       if (i >= 0 && i < 6) { 

        String var = "NO Keyword Found"; 
        Message completeMessage = mHandler.obtainMessage(); 
        completeMessage.obj = var; 

        completeMessage.sendToTarget(); 
        Log.v("FrameProcessor", "NO Keyword Found"); 

       } else if (i >= 6 && i < 12) { 

        **String var = "NO Keyword Found"; 
        Message completeMessage = mHandler.obtainMessage(); 
        completeMessage.obj = var; 

        completeMessage.sendToTarget();** 
        Log.v("FrameProcessor", "NO Keyword Found"); 

       } else if (i >= 12 && i < 18) { 
        String var = "NO Keyword Found"; 
        Message completeMessage = mHandler.obtainMessage(); 
        completeMessage.obj = var; 
        completeMessage.sendToTarget(); 
        Log.v("FrameProcessor", "NO Keyword Found"); 

       } else if (i > 18 && i < 24) { 
        String var = "NO Keyword Found"; 
        Message completeMessage = mHandler.obtainMessage(); 
        completeMessage.obj = var; 

        completeMessage.sendToTarget(); 
        Log.v("FrameProcessor", "NO Keyword Found"); 

       } else { 

       } 
       FileOutputStream fo = new FileOutputStream(f); 
       fo.write(bytes.toByteArray()); 

       fo.flush(); 
       fo.close(); 

       i++; 
      } 
     } else if (value.equals("1")) { 
      String folder = Environment.getExternalStorageDirectory() 
        .toString(); 

      File saveFolder = new File(folder + "/Movies/Frames/"); 

      if (!saveFolder.exists()) { 
       saveFolder.mkdirs(); 

       Log.v("FrameProcessor", "Extracting Frames.... "); 

      } 

      int i = 1; 
      for (Bitmap b : saveBitmapList) { 
       ByteArrayOutputStream bytes = new ByteArrayOutputStream(); 
       b.compress(Bitmap.CompressFormat.JPEG, 40, bytes); 

       File f = new File(saveFolder, ("frame" + i + ".jpg")); 

       f.createNewFile(); 
       if (i >= 0 && i < 6) { 

        String var = "NO Keyword Found"; 
        Message completeMessage = mHandler.obtainMessage(); 
        completeMessage.obj = var; 

        completeMessage.sendToTarget(); 
        Log.v("FrameProcessor", "NO Keyword Found"); 

       } else if (i >= 6 && i < 12) { 

        String var = "NO Keyword Found"; 
        Message completeMessage = mHandler.obtainMessage(); 
        completeMessage.obj = var; 

        completeMessage.sendToTarget(); 
        Log.v("FrameProcessor", "NO Keyword Found"); 

       } else if (i >= 12 && i < 18) { 
        String var = "NO Keyword Found"; 
        Message completeMessage = mHandler.obtainMessage(); 
        completeMessage.obj = var; 

        completeMessage.sendToTarget(); 
        Log.v("FrameProcessor", "NO Keyword Found"); 

       } else if (i > 18 && i < 24) { 
        String var = "NO Keyword Found"; 
        Message completeMessage = mHandler.obtainMessage(); 
        completeMessage.obj = var; 

        completeMessage.sendToTarget(); 
        Log.v("FrameProcessor", "NO Keyword Found"); 

       } else { 

       } 
       FileOutputStream fo = new FileOutputStream(f); 
       fo.write(bytes.toByteArray()); 

       fo.flush(); 
       fo.close(); 

       i++; 
      } 
     } else { 
      String folder = Environment.getExternalStorageDirectory() 
        .toString(); 

      File saveFolder = new File(folder + "/Movies/Frames/"); 

      if (!saveFolder.exists()) { 
       saveFolder.mkdirs(); 

       Log.v("FrameProcessor", "Extracting Frames.... "); 

      } 

      int i = 1; 
      while (bKeepRunning) { 

       for (Bitmap b : saveBitmapList) { 
        ByteArrayOutputStream bytes = new ByteArrayOutputStream(); 
        b.compress(Bitmap.CompressFormat.JPEG, 40, bytes); 

        File f = new File(saveFolder, ("frame" + i + ".jpg")); 

        f.createNewFile(); 
        if (i >= 0 && i < 6) { 

         String var = "Keyword HSN Found"; 
         Message completeMessage = mHandler.obtainMessage(); 
         completeMessage.obj = var; 

         completeMessage.sendToTarget(); 
         Log.v("FrameProcessor", "Keyword ABCFound"); 

        } else if (i >= 6 && i < 12) { 

         String var = "Keyword HSN Found"; 
         Message completeMessage = mHandler.obtainMessage(); 
         completeMessage.obj = var; 
         Log.v("FrameProcessor", "Keyword SHOP Found"); 

        } else if (i >= 12 && i < 18) { 
         String var = "Keyword HSN Found"; 
         Message completeMessage = mHandler.obtainMessage(); 
         completeMessage.obj = var; 
         Log.v("FrameProcessor", "Keyword BY Found"); 

        } else if (i > 18 && i < 24) { 
         String var = "Keyword HSN Found"; 
         Message completeMessage = mHandler.obtainMessage(); 
         completeMessage.obj = var; 
         Log.v("FrameProcessor", "Keyword REMOTE Found"); 

        } else { 

        } 
        FileOutputStream fo = new FileOutputStream(f); 
        fo.write(bytes.toByteArray()); 

        fo.flush(); 
        fo.close(); 

        i++; 
       } 
      } 
     } 
    } 

    public void kill() { 
     bKeepRunning = false; 
    } 
} 

Answer 1

Если обработчик имеет нулевое значение, вы можете использовать

Message.obtain() 

вместо. В любом случае вам нужно будет проверить, не обработан ли обработчик до отправки сообщения.