配置更改后方向对话框不更新（方向转为水平方向）

Question

当屏幕方向更改时，ProgressDialog退出更新。我已经制定了一个解决方案，它可以拯救asynctask，并在它被摧毁和重建之后，将asynctask的活动设置为新活动。 progressdialog上的完成百分比保持在定位更改之前的百分比。

我错过了什么？

package net.daleroy.fungifieldguide.activities; 

import java.io.BufferedInputStream; 
import java.io.FileOutputStream; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.net.URL; 
import java.net.URLConnection; 
import android.app.Activity; 
import android.app.Dialog; 
import android.app.ProgressDialog; 
import android.content.Intent; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.View; 
import android.view.Window; 
import android.view.View.OnClickListener; 
import android.widget.Toast; 
import net.daleroy.fungifieldguide.R; 
import net.daleroy.fungifieldguide.fungifieldguideapplication; 

public class FungiFieldGuide extends Activity { 
    //static final int PROGRESS_DIALOG = 0; 
    //ProgressThread progressThread; 
    private final static String LOG_TAG = FungiFieldGuide.class.getSimpleName(); 
    fungifieldguideapplication appState; 
    private DownloadFile mTask; 
    public boolean mShownDialog; 
    ProgressDialog progressDialog; 
    private final static int DIALOG_ID = 1; 

    @Override 
    protected void onPrepareDialog(int id, Dialog dialog) { 
     super.onPrepareDialog(id, dialog); 

     if (id == DIALOG_ID) { 
      mShownDialog = true; 
     } 
    } 

    private void onTaskCompleted() { 
     Log.i(LOG_TAG, "Activity " + this + " has been notified the task is complete."); 

     //Check added because dismissDialog throws an exception if the current 
     //activity hasn't shown it. This Happens if task finishes early enough 
     //before an orientation change that the dialog is already gone when 
     //the previous activity bundles up the dialogs to reshow. 
     if (mShownDialog) { 
      dismissDialog(DIALOG_ID); 
      Toast.makeText(this, "Finished..", Toast.LENGTH_LONG).show(); 
     } 
    } 

    @Override 
    protected Dialog onCreateDialog(int id) { 
     switch(id) { 
     case DIALOG_ID: 
      progressDialog = new ProgressDialog(this); 
      progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); 
      progressDialog.setMessage("Loading Database (only first run)..."); 
      return progressDialog; 
     default: 
      return super.onCreateDialog(id); 
     } 
    } 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     requestWindowFeature(Window.FEATURE_NO_TITLE); 
     setContentView(R.layout.main); 
     appState = ((fungifieldguideapplication)this.getApplication()); 

     Object retained = getLastNonConfigurationInstance(); 
     if (retained instanceof DownloadFile) { 
      Log.i(LOG_TAG, "Reclaiming previous background task."); 
      mTask = (DownloadFile) retained; 
      mTask.setActivity(this); 
      //showDialog(DIALOG_ID); 
     } 
     else { 
      if(!appState.service.createDataBase()) 
      { 
       Log.i(LOG_TAG, "Creating new background task."); 
       //showDialog(DIALOG_ID); 
       mTask = new DownloadFile(this); 
       mTask.execute("http://www.codemarshall.com/Home/Download"); 
      } 
     } 
      //showDialog(PROGRESS_DIALOG); 

     View btn_Catalog = findViewById(R.id.btn_Catalog); 
     btn_Catalog.setOnClickListener(new OnClickListener() 
     { 
      public void onClick(View v) 
      { 
       Intent i = new Intent(getBaseContext(), Cat_Genus.class);//new Intent(this, Total.class); 
       startActivity(i); 
      } 
     }); 

     View btn_Search = findViewById(R.id.btn_Search); 
     btn_Search.setOnClickListener(new OnClickListener() 
     { 
      public void onClick(View v) 
      { 
       Intent i = new Intent(getBaseContext(), Search.class);//new Intent(this, Total.class); 
       startActivity(i); 
      } 
     }); 
    } 

    @Override 
    public Object onRetainNonConfigurationInstance() { 
      mTask.setActivity(null); 
      return mTask; 
    } 

    @Override 
    public void onDestroy() 
    { 
     super.onDestroy(); 
     //progressDialog.dismiss(); 
     //progressDialog = null; 
     appState.service.ClearSearchParameters(); 
    } 

    private class DownloadFile extends AsyncTask<String, Integer, Boolean>{ 
     private FungiFieldGuide activity; 
     private boolean completed; 
     private String Error = null; 
     private String Content; 

     private DownloadFile(FungiFieldGuide activity) { 
      this.activity = activity; 
     } 

     @Override 
     protected void onPreExecute() 
     { 
      showDialog(DIALOG_ID); 
     } 


     @Override 
     protected Boolean doInBackground(String... urlarg) { 
      int count; 

      try { 
       URL url = new URL(urlarg[0]); 
       URLConnection conexion = url.openConnection(); 
       conexion.setDoInput(true); 
       conexion.setUseCaches(false); 

       // this will be useful so that you can show a tipical 0-100% progress bar 
       int lenghtOfFile = conexion.getContentLength(); 

       // downlod the file 
       InputStream input = new BufferedInputStream(conexion.getInputStream()); 
       OutputStream output = new FileOutputStream("/data/data/net.daleroy.fungifieldguide/databases/Mushrooms.db"); 

       byte data[] = new byte[1024]; 

       long total = 0; 

       while ((count = input.read(data)) != -1) { 
        total += count; 
        // publishing the progress.... 
        publishProgress((int)total*100/lenghtOfFile); 
        output.write(data, 0, count); 
       } 

       output.flush(); 
       output.close(); 
       input.close(); 
      } catch (Exception e) { 
       Log.i(LOG_TAG, e.getMessage()); 
      } 
      return null; 
     } 

     @Override 
     public void onProgressUpdate(Integer... args){ 
      progressDialog.setProgress(args[0]); 
     } 

     @Override 
     protected void onPostExecute(Boolean result) 
     { 
      completed = true; 
      notifyActivityTaskCompleted(); 
     } 

     private void notifyActivityTaskCompleted() { 
      if (null != activity) { 
       activity.onTaskCompleted(); 
      } 
     } 

     private void setActivity(FungiFieldGuide activity) { 
      this.activity = activity; 
      if (completed) { 
        notifyActivityTaskCompleted(); 
      } 
     } 
    } 
} 

Answer 1

这不能不防止的AsyncTask的生命在此我只是禁用取向的变化与添加第一个真正的解决办法：

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_NOSENSOR);

，当任务完成：

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);

希望这会有所帮助。