Android progressdialog和asynktask衝突

Question

我已經開發了一個簡單的asynctask，並附有progressdialog，以顯示給定任務的進度。

他們工作很好，沒有任何問題，而沒有方向變化發生。我改變了設備的方向（我在真實設備上測試），對話框出現在窗口中。

我嘗試了手動解除進度對話框，當方向改變時，但沒有任何東西似乎影響對話框。

這裏是我的AsyncTask代碼：

class DownloadFileAsync extends AsyncTask<String, String, String>{ 

    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     showDialog(DOWNLOAD_PROGRESS_DIALOG); 
    } 

    @Override 
    protected String doInBackground(String... params) { 
     File file = null; 
     try { 
      URL url = new URL(fileURL); 
      file = new File(fileName); 

      if(!file.exists()){ 
       file.createNewFile(); 
      }else{ 
       return "0"; 
      } 

      /* Open a connection to that URL. */ 
      URLConnection ucon = url.openConnection(); 

      int lenghtOfFile = ucon.getContentLength(); 
      /* 
      * Define InputStreams to read from the URLConnection. 
      */ 
      InputStream is = ucon.getInputStream(); 
      FileOutputStream fos = new FileOutputStream(file); 

      byte[] buffer = new byte[1024]; 
      int len1 = 0; 
      long total = 0; 
      while((len1 = is.read(buffer)) > 0){ 
       total += len1; 
       publishProgress("" + (int) ((total*100)/lenghtOfFile)); 
       fos.write(buffer, 0, len1); 
      } 
      fos.close(); 

      return "1"; 
     } catch (IOException e) { 
      if(file != null && file.exists()){ 
       file.delete(); 
      } 
      dismissDialog(DOWNLOAD_PROGRESS_DIALOG); 

     } 
     return "0"; 
    } 
    @Override 
    protected void onProgressUpdate(String... values) { 
     try{ 
      downloadProgress.setProgress(Integer.parseInt(values[0])); 
     }catch(Exception e){ 

     } 
    } 

    @Override 
    protected void onPostExecute(String result) { 
     downloadResult = result;  
     dismissDialog(DOWNLOAD_PROGRESS_DIALOG); 
    } 

} 

而以下是我oncreatedialog

@Override 
protected Dialog onCreateDialog(int id) { 
... 
}case(DOWNLOAD_PROGRESS_DIALOG):{ 
     if(downloadProgress == null){ 
      downloadProgress = new ProgressDialog(this); 
      downloadProgress.setOnDismissListener(new DialogInterface.OnDismissListener() { 
       @Override 
       public void onDismiss(DialogInterface dialog) { 
        if(downloadResult == "1"){ 
         FileStored newFileStored = new FileStored(fileName, new Date()); 
         db.insertFile(newFileStored); 
         refreshLastDownload(); 
         downloadResult = null; 
        }else{ 
         showDialog(DOWNLOAD_PROBLEM); 
        } 
        downloadProgress = null; 
       } 
      }); 
      Resources r = getResources(); 
      downloadProgress.setMessage(r.getString(R.string.downloading)); 
      downloadProgress.setIndeterminate(false); 
      downloadProgress.setMax(100); 
      downloadProgress.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); 
      downloadProgress.setCancelable(true); 
      downloadProgress.show(); 
     } 
     return downloadProgress; 
    }case(DOWNLOAD_PROBLEM):{ 
     if(this.downloadProblemDialog == null){ 
      TextView problemView = new TextView(this); 
      problemView.setText(R.string.problem_download_text); 
      AlertDialog.Builder problemDialog = new AlertDialog.Builder(this); 
      problemDialog.setTitle(R.string.problem_download); 
      problemDialog.setView(problemView); 
      problemDialog.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int which) { 

       } 
      }); 
      this.downloadProblemDialog = problemDialog.create(); 
     } 
     return this.downloadProblemDialog; 
    } 
... 

最後，調用異步任務

new DownloadFileAsync().execute(fileURL); 

你能發現什麼不對的線索到這個方向改變怪異的行爲？

謝謝你在前進，

Vyrphan

Answer 1

添加以下屬性在Android清單文件的活動。

<activity android:name=".name" android:label="@string/app_name" 
    android:configChanges="touchscreen|keyboard|keyboardHidden|navigation|orientation"></activity> 

Answer 2

當設備的方向改變時，android生命週期從onCreate方法重複。 所以要處理你的進度對話框的方向變化，你有兩種選擇，一種是設置配置變化活動標誌爲方向。而另一種選擇是保留狀態翻過配置更改，請參閱鏈接：

How to save state during orientation change in Android if the state is made of my classes?