下載時出現通知錯誤

Question

我在網上使用了一些代碼 - 但我仍然不知道爲什麼它不工作... 如果我拿出Notification的東西，那麼它下載罰款（在後臺- 不好！）。但是，每當我包括他們，它迫使退出，我不知道爲什麼！

通知設置

Intent intent = new Intent(this, ListActivity.class); 
    final PendingIntent pendingIntent = PendingIntent.getActivity(getApplicationContext(), 0, intent, 0); 

    // configure the notification 
    final Notification notification = new Notification(R.drawable.icon, "Downloading Rom via RomGet", System 
      .currentTimeMillis()); 
    notification.flags = notification.flags | Notification.FLAG_ONGOING_EVENT; 
    notification.contentView = new RemoteViews(getApplicationContext().getPackageName(), R.layout.layout_download); 
    notification.contentIntent = pendingIntent; 
    notification.contentView.setImageViewResource(R.id.status_icon, R.drawable.icon_rom); 
    notification.contentView.setTextViewText(R.id.download_description, "Downloading"); 
    notification.contentView.setProgressBar(R.id.download_progress, 100, 0, false); 
    notification.icon = R.drawable.ic_stat_rom; 

    final NotificationManager notificationManager = (NotificationManager) getApplicationContext().getSystemService(
      getApplicationContext().NOTIFICATION_SERVICE); 

    notificationManager.notify(43, notification); 

下載類

public void run() {   
     try { 
      // Setup download things here - all good 

      totalSize = urlConnection.getContentLength(); 

      //create a buffer... 
      byte[] buffer = new byte[1024]; 
      int bufferLength = 0; //used to store a temporary size of the buffer 

      //now, read through the input buffer and write the contents to the file 
      while ((bufferLength = inputStream.read(buffer)) > 0) { 
       //add the data in the buffer to the file in the file output stream (the file on the sd card 
       fileOutput.write(buffer, 0, bufferLength); 
       //add up the size so we know how much is downloaded 
       downloadedSize += bufferLength; 
       //this is where you would do something to report the prgress, like this maybe 

       handler.sendEmptyMessage(0); 
      } 
      //close the output stream when done 
      fileOutput.close(); 

     //catch some possible errors... 
     } catch (MalformedURLException e) { 
      e.printStackTrace(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
     // see http://androidsnippets.com/download-an-http-file-to-sdcard-with-progress-notificationØ 
    } 

    private Handler handler = new Handler() { 

     @Override 
     public void handleMessage(Message msg) { 
      //notification.setProgressBar(R.id.download_progress, Math.round(totalSize), Math.round(downloadedSize), false); 
      notification.contentView.setTextViewText(R.id.download_description, Integer.toString(downloadedSize)); 
      // inform the progress bar of updates in progress 
      notificationManager.notify(43, notification); 
     } 
    }; 
} 

這是它給我的錯誤：

05-31 22:48:23.539: DEBUG/AndroidRuntime(24431): Shutting down VM 
05-31 22:48:23.539: WARN/dalvikvm(24431): threadid=1: thread exiting with uncaught exception (group=0x40015560) 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431): FATAL EXCEPTION: main 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431): java.lang.NullPointerException 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431):  at com.ezeh.romget.ListActivity$DownloadThread$1.handleMessage(ListActivity.java:285) 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431):  at android.os.Handler.dispatchMessage(Handler.java:99) 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431):  at android.os.Looper.loop(Looper.java:123) 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431):  at android.app.ActivityThread.main(ActivityThread.java:3835) 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431):  at java.lang.reflect.Method.invokeNative(Native Method) 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431):  at java.lang.reflect.Method.invoke(Method.java:507) 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841) 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599) 
05-31 22:48:23.542: ERROR/AndroidRuntime(24431):  at dalvik.system.NativeStart.main(Native Method) 
05-31 22:48:23.558: WARN/ActivityManager(13390): Force finishing activity com.ezeh.romget/.ListActivity 
05-31 22:48:24.074: WARN/ActivityManager(13390): Activity pause timeout for HistoryRecord{407e8090 com.ezeh.romget/.ListActivity} 
05-31 22:48:29.386: INFO/Process(24431): Sending signal. PID: 24431 SIG: 9 
05-31 22:48:29.460: INFO/ActivityManager(13390): Process com.ezeh.romget (pid 24431) has died. 
05-31 22:48:29.464: INFO/WindowManager(13390): WIN DEATH: Window{408fbb18 com.ezeh.romget/com.ezeh.romget.ListActivity paused=false} 
05-31 22:48:29.468: INFO/DemoService(13809): DiyScheduer.onStart 
05-31 22:48:29.468: INFO/ggheart(13809): onStart 
05-31 22:48:29.472: INFO/WindowManager(13390): WIN DEATH: Window{40863a78 com.ezeh.romget/com.ezeh.romget.HomeActivity paused=false} 
05-31 22:48:29.484: INFO/rxq(13809): onResume() 
05-31 22:48:34.644: DEBUG/dalvikvm(24165): GC_EXPLICIT freed 87K, 49% free 3507K/6791K, external 0K/0K, paused 28ms 

Answer 1

要使用的應用程序凍結你的新問題而下載，你實際上是通過下載本身阻止UI進程。解決方法是使用AsyncTask在後臺執行下載。 Google有一個AsyncTasks here的介紹。還有很多關於如何在線下載後臺文件的好資源。