如何解决在Android中拒绝执行的异常

Question

public class TopMovie extends Activity { 
    GridView lv; 
    Vibrator vibrator; 
    private Object params; 
    public static String movie_Id; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     super.onCreate(savedInstanceState); 
     Log.i("Category", MainActivity.movie_Category); 
     setContentView(R.layout.new_movie); 
     LayoutInflater inflater = getLayoutInflater(); 
     View view = inflater.inflate(R.layout.customtoast, 
       (ViewGroup) findViewById(R.id.custom_toast_layout)); 
     Toast toast = new Toast(getApplicationContext()); 
     toast.setDuration(Toast.LENGTH_LONG); 
     toast.setGravity(Gravity.CENTER_HORIZONTAL, 0, 0); 
     toast.setView(view); 
     toast.show(); 

     vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE); 
     lv = (GridView) findViewById(R.id.grid_view); 

     // URL to the JSON data 
     String strUrl = "http://vaibhavtech.com/work/android/movie_list.php?category=" 
       + MainActivity.movie_Category + "&sub_category=other"; 
     DownloadTask downloadTask = new DownloadTask(); 
     downloadTask.execute(strUrl); 
     lv.setOnItemClickListener(new OnItemClickListener() { 

      @Override 
      public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, 
        long arg3) { 
       // // TODO Auto-generated method stub 
       vibrator.vibrate(40); 
       LayoutInflater inflater = getLayoutInflater(); 
       View view = inflater.inflate(R.layout.customtoast, 
         (ViewGroup) findViewById(R.id.custom_toast_layout)); 
       Toast toast = new Toast(getApplicationContext()); 
       toast.setDuration(Toast.LENGTH_LONG); 
       toast.setGravity(Gravity.CENTER_HORIZONTAL, 0, 0); 
       toast.setView(view); 
       toast.show(); 
       MainActivity.movie_Id = ((TextView) arg1 
         .findViewById(R.id.tv_girdview_content_id)).getText() 
         .toString(); 
       Log.i("Name is", MainActivity.movie_Id); 
       startActivity(new Intent(TopMovie.this, MovieDescription.class)); 
      } 
     }); 
    } 

    private String downloadUrl(String strUrl) throws IOException { 
     String data = ""; 
     InputStream iStream = null; 
     try { 
      URL url = new URL(strUrl); 

      // Creating an http connection to communicate with url 
      HttpURLConnection urlConnection = (HttpURLConnection) url 
        .openConnection(); 

      // Connecting to url 
      urlConnection.connect(); 

      // Reading data from url 
      iStream = urlConnection.getInputStream(); 

      BufferedReader br = new BufferedReader(new InputStreamReader(
        iStream)); 

      StringBuffer sb = new StringBuffer(); 
      String line = ""; 

      while ((line = br.readLine()) != null) { 
       sb.append(line); 
      } 

      data = sb.toString(); 

      br.close(); 
     } catch (Exception e) { 
      Log.d("Exception while downloading url", e.toString()); 
     } finally { 
      iStream.close(); 
     } 

     return data; 
    } 

    /** AsyncTask to download json data */ 
    private class DownloadTask extends AsyncTask<String, Integer, String> { 
     String data = null; 

     @Override 
     protected String doInBackground(String... url) { 
      try { 
       data = downloadUrl(url[0]); 
      } catch (Exception e) { 
       Log.d("Background Task", e.toString()); 
      } 
      return data; 
     } 

     @Override 
     protected void onPostExecute(String result) { 

      // The parsing of the xml data is done in a non-ui thread 
      ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask(); 

      // Start parsing xml data 
      listViewLoaderTask.execute(result); 
     } 
    } 

    /** AsyncTask to parse json data and load ListView */ 
    private class ListViewLoaderTask extends 
      AsyncTask<String, Void, SimpleAdapter> { 

     JSONObject jObject; 

     // Doing the parsing of xml data in a non-ui thread 
     @Override 
     protected SimpleAdapter doInBackground(String... strJson) { 
      try { 
       jObject = new JSONObject(strJson[0]); 
       MovieParser countryJsonParser = new MovieParser(); 
       countryJsonParser.parse(jObject); 
      } catch (Exception e) { 
       Log.d("JSON Exception1", e.toString()); 
      } 

      // Instantiating json parser class 
      MovieParser countryJsonParser = new MovieParser(); 

      // A list object to store the parsed countries list 
      List<HashMap<String, Object>> countries = null; 

      try { 
       // Getting the parsed data as a List construct 
       countries = countryJsonParser.parse(jObject); 
      } catch (Exception e) { 
       Log.d("Exception", e.toString()); 
      } 

      // Keys used in Hashmap 
      String[] from = { "image", "id", "year", "duration", "name" }; 

      // Ids of views in listview_layout 
      // int[] to = { 
      // R.id.iv_radio_data_image,R.id.tv_radio_data_id,R.id.tv_radio_data_like,R.id.tv_radio_data_rating,R.id.tv_radio_data_listner,R.id.tv_radio_data_radio_url,R.id.tv_radio_data_name}; 
      int[] to = { R.id.iv_girdview_content_image, 
        R.id.tv_girdview_content_id, R.id.tv_girdview_content_like, 
        R.id.tv_girdview_content_listner, 
        R.id.tv_girdview_content_name }; 

      SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), 
        countries, R.layout.grid_view_content, from, to); 

      return adapter; 
     } 

     /** Invoked by the Android on "doInBackground" is executed */ 
     @Override 
     protected void onPostExecute(SimpleAdapter adapter) { 

      // Setting adapter for the listview 
      lv.setAdapter(adapter); 

      for (int i = 0; i < adapter.getCount(); i++) { 
       HashMap<String, Object> hm = (HashMap<String, Object>) adapter 
         .getItem(i); 
       String imgUrl = (String) hm.get("flag_path"); 
       ImageLoaderTask imageLoaderTask = new ImageLoaderTask(); 

       HashMap<String, Object> hmDownload = new HashMap<String, Object>(); 
       hm.put("flag_path", imgUrl); 
       hm.put("position", i); 

       // Starting ImageLoaderTask to download and populate image in 
       // the listview 
       imageLoaderTask.execute(hm); 
      } 
     } 
    } 

    /** AsyncTask to download and load an image in ListView */ 
    private class ImageLoaderTask extends AsyncTask<HashMap<String, Object>, Void, HashMap<String, Object>> { 

     @Override 
     protected HashMap<String, Object> doInBackground(HashMap<String, Object>... hm) { 

      InputStream iStream = null; 
      String imgUrl = (String) hm[0].get("flag_path"); 
      int position = (Integer) hm[0].get("position"); 

      URL url; 
      try { 
       url = new URL(imgUrl); 

       // Creating an http connection to communicate with url 
       HttpURLConnection urlConnection = (HttpURLConnection) url 
         .openConnection(); 

       // Connecting to url 
       urlConnection.connect(); 

       // Reading data from url 
       iStream = urlConnection.getInputStream(); 

       // Getting Caching directory 
       File cacheDirectory = getBaseContext().getCacheDir(); 

       // Temporary file to store the downloaded image 
       File tmpFile = new File(cacheDirectory.getPath() + "/wpta_" 
         + position + ".png"); 

       // The FileOutputStream to the temporary file 
       FileOutputStream fOutStream = new FileOutputStream(tmpFile); 

       // Creating a bitmap from the downloaded inputstream 
       Bitmap b = BitmapFactory.decodeStream(iStream); 

       // Writing the bitmap to the temporary file as png file 
       b.compress(Bitmap.CompressFormat.PNG, 100, fOutStream); 

       // Flush the FileOutputStream 
       fOutStream.flush(); 

       // Close the FileOutputStream 
       fOutStream.close(); 

       // Create a hashmap object to store image path and its position 
       // in the listview 
       HashMap<String, Object> hmBitmap = new HashMap<String, Object>(); 

       // Storing the path to the temporary image file 
       hmBitmap.put("image", tmpFile.getPath()); 

       // Storing the position of the image in the listview 
       hmBitmap.put("position", position); 

       // Returning the HashMap object containing the image path and 
       // position 
       return hmBitmap; 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
      return null; 
     } 

     @Override 
     protected void onPostExecute(HashMap<String, Object> result) { 
      // Getting the path to the downloaded image 
      String path = (String) result.get("image"); 

      // Getting the position of the downloaded image 
      int position = (Integer) result.get("position"); 

      // Getting adapter of the listview 
      SimpleAdapter adapter = (SimpleAdapter) lv.getAdapter(); 

      // Getting the hashmap object at the specified position of the 
      // listview 
      HashMap<String, Object> hm = (HashMap<String, Object>) adapter 
        .getItem(position); 

      // Overwriting the existing path in the adapter 
      hm.put("image", path); 
      adapter.notifyDataSetChanged(); 
     } 
    } 
} 

在使用AsyncTask之后，它在我的代码中发出异常。我究竟做错了什么？

的logcat的低于：

RejectedExecutionException: Task rejected from java.util.concurrent.ThreadPoolExecutorRunning, pool size = 128, active threads = 128, queued tasks = 10, completed tasks = 4] 

10-26 08:39:30.797: E/AndroidRuntime(4404): FATAL EXCEPTION: main 
10-26 08:39:30.797: E/AndroidRuntime(4404): java.util.concurrent.RejectedExecutionException: Task android.os.AsyncTask$3@411eb538 rejected from java.util.concurrent.ThreadPoolExecutor@40ce4100[Running, pool size = 128, active threads = 128, queued tasks = 10, completed tasks = 4] 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:1979) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:786) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1307) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:589) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at android.os.AsyncTask.execute(AsyncTask.java:534) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at target.mymovie.TopMovie$ListViewLoaderTask.onPostExecute(TopMovie.java:236) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at target.mymovie.TopMovie$ListViewLoaderTask.onPostExecute(TopMovie.java:1) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at android.os.AsyncTask.finish(AsyncTask.java:631) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at android.os.AsyncTask.access$600(AsyncTask.java:177) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at android.os.Handler.dispatchMessage(Handler.java:99) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at android.os.Looper.loop(Looper.java:137) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at android.app.ActivityThread.main(ActivityThread.java:5041) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at java.lang.reflect.Method.invokeNative(Native Method) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at java.lang.reflect.Method.invoke(Method.java:511) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
10-26 08:39:30.797: E/AndroidRuntime(4404):  at dalvik.system.NativeStart.main(Native Method) 
10-26 08:39:33.097: I/Process(4404): Sending signal. PID: 4404 SIG: 9 
10-26 08:39:34.427: E/Trace(4575): error opening trace file: No such file or directory (2) 
10-26 08:39:34.977: D/dalvikvm(4575): GC_FOR_ALLOC freed 67K, 8% free 2494K/2684K, paused 33ms, total 36ms 
10-26 08:39:34.997: I/dalvikvm-heap(4575): Grow heap (frag case) to 4.016MB for 1536016-byte allocation 
10-26 08:39:35.107: D/dalvikvm(4575): GC_FOR_ALLOC freed 2K, 5% free 3992K/4188K, paused 104ms, total 104ms 
10-26 08:39:35.157: D/dalvikvm(4575): GC_CONCURRENT freed <1K, 5% free 3992K/4188K, paused 4ms+14ms, total 52ms 
10-26 08:39:35.767: D/dalvikvm(4575): GC_CONCURRENT freed 4K, 4% free 4428K/4608K, paused 73ms+4ms, total 144ms 
10-26 08:39:36.067: D/gralloc_goldfish(4575): Emulator without GPU emulation detected. 

Answer 1

RejectedExecutionException： 异常通过当一个任务不能执行 可以接受一个Executor抛出。

AsyncTask一次支持10个并发线程和10个排队线程。

您致电imageLoaderTask.execute(hm);太多次在for loop这是造成问题，是一种不好的做法。

相反，你可以启动一个线程，并将其收集所有的图像在一个循环，而他们都在 onPostExecute添加到适配器。

Answer 2

如果您的Executor调用关闭方法，并且在给出新的Task（Runnable）以供执行之后，也会发生此异常。 像 mThreadPoolExecutor.shutdown(); ... ... ... mThreadPoolExecutor.execute(new Runnable(){...});