对于这些问题，我想出了一个坚如磐石的解决方案，它符合“Android方式”。我使用IntentService模式进行所有长时间运行的操作。

也就是说，我的活动广播意图，IntentService负责工作，将数据保存在DB中，然后广播粘性意图。粘性部分很重要，即使Activity在用户启动工作后暂停，并且错过了来自IntentService的实时广播，我们仍然可以响应并从调用Activity中获取数据。progressdialog可以很好地使用onSaveInstanceState()与此模式一起工作。

Basically, you need to save a flag that you have a progress dialog running in the saved instance bundle. Do not save the progress dialog object because this will leak the entire Activity. To have a persistent handle to the progress dialog, I store it as a weak reference in the application object. On orientation change or anything else that causes the Activity to pause (phone call, user hits home etc.) and then resume, I dismiss the old dialog and recreate a new dialog in the newly created Activity.

对于无限进度对话框来说，这很容易。对于进度条样式，您必须将最后一个已知的进度放在bundle中，并将您在活动中本地使用的任何信息用于跟踪进度。在恢复进度时，您将使用此信息以与之前相同的状态重新生成进度条，然后根据当前状态进行更新。

总之，将长时间运行的任务放到IntentService中，再加上明智地使用onSaveInstanceState()，可以让你有效地跟踪对话框，并在活动生命周期事件中恢复对话框。活动代码的相关部分如下。您还需要BroadcastReceiver中的逻辑来适当地处理Sticky意图，但这超出了本文的范围。

public void doSignIn(View view) {
    waiting=true;
    AppClass app=(AppClass) getApplication();
    String logingon=getString(R.string.signon);
    app.Dialog=new WeakReference<ProgressDialog>(ProgressDialog.show(AddAccount.this, "", logingon, true));
    ...
}

@Override
protected void onSaveInstanceState(Bundle saveState) {
    super.onSaveInstanceState(saveState);
    saveState.putBoolean("waiting",waiting);
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if(savedInstanceState!=null) {
        restoreProgress(savedInstanceState);    
    }
    ...
}

private void restoreProgress(Bundle savedInstanceState) {
    waiting=savedInstanceState.getBoolean("waiting");
    if (waiting) {
        AppClass app=(AppClass) getApplication();
        ProgressDialog refresher=(ProgressDialog) app.Dialog.get();
        refresher.dismiss();
        String logingon=getString(R.string.signon);
        app.Dialog=new WeakReference<ProgressDialog>(ProgressDialog.show(AddAccount.this, "", logingon, true));
    }
}

我也遇到过同样的问题。我的活动需要从一个URL解析一些数据，它很慢。所以我创建了一个线程来完成这个任务，然后显示一个进度对话框。当线程完成时，我让线程通过处理程序发布消息回UI线程。在处理程序。handleMessage，我从线程获得数据对象(现在准备好了)，并将其填充到UI。这和你的例子很相似。

经过反复试验，我似乎找到了解决办法。至少现在我可以在任何时候旋转屏幕，在线程完成之前或之后。在所有测试中，对话框都是正确关闭的，所有行为都符合预期。

我所做的如下所示。目标是填充我的数据模型(mDataObject)，然后将其填充到UI。应该允许屏幕旋转在任何时候没有意外。

class MyActivity {

    private MyDataObject mDataObject = null;
    private static MyThread mParserThread = null; // static, or make it singleton

    OnCreate() {
        ...
        Object retained = this.getLastNonConfigurationInstance();
        if(retained != null) {
            // data is already completely obtained before config change
            // by my previous self.
            // no need to create thread or show dialog at all
            mDataObject = (MyDataObject) retained;
            populateUI();
        } else if(mParserThread != null && mParserThread.isAlive()){
            // note: mParserThread is a static member or singleton object.
            // config changed during parsing in previous instance. swap handler
            // then wait for it to finish.
            mParserThread.setHandler(new MyHandler());
        } else {
            // no data and no thread. likely initial run
            // create thread, show dialog
            mParserThread = new MyThread(..., new MyHandler());
            mParserThread.start();
            showDialog(DIALOG_PROGRESS);
        }
    }

    // http://android-developers.blogspot.com/2009/02/faster-screen-orientation-change.html
    public Object onRetainNonConfigurationInstance() {
        // my future self can get this without re-downloading
        // if it's already ready.
        return mDataObject;
    }

    // use Activity.showDialog instead of ProgressDialog.show
    // so the dialog can be automatically managed across config change
    @Override
    protected Dialog onCreateDialog(int id) {
        // show progress dialog here
    }

    // inner class of MyActivity
    private class MyHandler extends Handler {
        public void handleMessage(msg) {
            mDataObject = mParserThread.getDataObject();
            populateUI();
            dismissDialog(DIALOG_PROGRESS);
        }
    }
}

class MyThread extends Thread {
    Handler mHandler;
    MyDataObject mDataObject;

    // constructor with handler param
    public MyHandler(..., Handler h) {
        ...
        mHandler = h;
    }

    public void setHandler(Handler h) { mHandler = h; } // for handler swapping after config change
    public MyDataObject getDataObject() { return mDataObject; } // return data object (completed) to caller

    public void run() {
        mDataObject = new MyDataObject();
        // do the lengthy task to fill mDataObject with data
        lengthyTask(mDataObject);
        // done. notify activity
        mHandler.sendEmptyMessage(0); // tell activity: i'm ready. come pick up the data.
    }
}

这对我来说很有效。我不知道这是否是Android设计的“正确”方法——他们声称这种“在屏幕旋转期间破坏/重建活动”实际上使事情变得更简单，所以我猜这应该不是太棘手。

如果您在我的代码中发现问题，请告诉我。如上所述，我真的不知道是否有任何副作用。

我将贡献我处理这个轮换问题的方法。这可能与OP无关，因为他没有使用AsyncTask，但其他人可能会发现它很有用。这很简单，但它似乎为我做的工作:

我有一个带有嵌套AsyncTask类的登录活动，称为BackgroundLoginTask。

在我的BackgroundLoginTask中，我没有做任何不寻常的事情，除了在调用ProgressDialog的dismiss时添加一个空检查:

@Override
protected void onPostExecute(Boolean result)
{    
if (pleaseWaitDialog != null)
            pleaseWaitDialog.dismiss();
[...]
}

这是为了处理后台任务完成而活动不可见的情况，因此，进度对话框已经被onPause()方法解散。

接下来，在我的父Activity类中，我为我的AsyncTask类和我的ProgressDialog创建了全局静态句柄(AsyncTask被嵌套，可以访问这些变量):

private static BackgroundLoginTask backgroundLoginTask;
private static ProgressDialog pleaseWaitDialog;

这有两个目的:首先，它允许我的活动总是访问AsyncTask对象，即使是从一个新的，后旋转的活动。其次，它允许我的BackgroundLoginTask访问和解散ProgressDialog，即使在旋转之后。

接下来，我将此添加到onPause()，导致进度对话框在我们的活动离开前台时消失(防止丑陋的“强制关闭”崩溃):

    if (pleaseWaitDialog != null)
    pleaseWaitDialog.dismiss();

最后，我在onResume()方法中有以下内容:

if ((backgroundLoginTask != null) && (backgroundLoginTask.getStatus() == Status.RUNNING))
        {
           if (pleaseWaitDialog != null)
             pleaseWaitDialog.show();
        }

这允许对话框在活动被重新创建后重新出现。

这是整个班级:

public class NSFkioskLoginActivity extends NSFkioskBaseActivity {
    private static BackgroundLoginTask backgroundLoginTask;
    private static ProgressDialog pleaseWaitDialog;
    private Controller cont;

    // This is the app entry point.
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (CredentialsAvailableAndValidated())
        {
        //Go to main menu and don't run rest of onCreate method.
            gotoMainMenu();
            return;
        }
        setContentView(R.layout.login);
        populateStoredCredentials();   
    }

    //Save current progress to options when app is leaving foreground
    @Override
    public void onPause()
    {
        super.onPause();
        saveCredentialsToPreferences(false);
        //Get rid of progress dialog in the event of a screen rotation. Prevents a crash.
        if (pleaseWaitDialog != null)
        pleaseWaitDialog.dismiss();
    }

    @Override
    public void onResume()
    {
        super.onResume();
        if ((backgroundLoginTask != null) && (backgroundLoginTask.getStatus() == Status.RUNNING))
        {
           if (pleaseWaitDialog != null)
             pleaseWaitDialog.show();
        }
    }

    /**
     * Go to main menu, finishing this activity
     */
    private void gotoMainMenu()
    {
        startActivity(new Intent(getApplicationContext(), NSFkioskMainMenuActivity.class));
        finish();
    }

    /**
     * 
     * @param setValidatedBooleanTrue If set true, method will set CREDS_HAVE_BEEN_VALIDATED to true in addition to saving username/password.
     */
    private void saveCredentialsToPreferences(boolean setValidatedBooleanTrue)
    {
        SharedPreferences settings = getSharedPreferences(APP_PREFERENCES, MODE_PRIVATE);
        SharedPreferences.Editor prefEditor = settings.edit();
        EditText usernameText = (EditText) findViewById(R.id.editTextUsername);
        EditText pswText = (EditText) findViewById(R.id.editTextPassword);
        prefEditor.putString(USERNAME, usernameText.getText().toString());
        prefEditor.putString(PASSWORD, pswText.getText().toString());
        if (setValidatedBooleanTrue)
        prefEditor.putBoolean(CREDS_HAVE_BEEN_VALIDATED, true);
        prefEditor.commit();
    }

    /**
     * Checks if user is already signed in
     */
    private boolean CredentialsAvailableAndValidated() {
        SharedPreferences settings = getSharedPreferences(APP_PREFERENCES,
                MODE_PRIVATE);
        if (settings.contains(USERNAME) && settings.contains(PASSWORD) && settings.getBoolean(CREDS_HAVE_BEEN_VALIDATED, false) == true)
         return true;   
        else
        return false;
    }

    //Populate stored credentials, if any available
    private void populateStoredCredentials()
    {
        SharedPreferences settings = getSharedPreferences(APP_PREFERENCES,
            MODE_PRIVATE);
        settings.getString(USERNAME, "");
       EditText usernameText = (EditText) findViewById(R.id.editTextUsername);
       usernameText.setText(settings.getString(USERNAME, ""));
       EditText pswText = (EditText) findViewById(R.id.editTextPassword);
       pswText.setText(settings.getString(PASSWORD, ""));
    }

    /**
     * Validate credentials in a seperate thread, displaying a progress circle in the meantime
     * If successful, save credentials in preferences and proceed to main menu activity
     * If not, display an error message
     */
    public void loginButtonClick(View view)
    {
        if (phoneIsOnline())
        {
        EditText usernameText = (EditText) findViewById(R.id.editTextUsername);
        EditText pswText = (EditText) findViewById(R.id.editTextPassword);
           //Call background task worker with username and password params
           backgroundLoginTask = new BackgroundLoginTask();
           backgroundLoginTask.execute(usernameText.getText().toString(), pswText.getText().toString());
        }
        else
        {
        //Display toast informing of no internet access
        String notOnlineMessage = getResources().getString(R.string.noNetworkAccessAvailable);
        Toast toast = Toast.makeText(getApplicationContext(), notOnlineMessage, Toast.LENGTH_SHORT);
        toast.show();
        }
    }

    /**
     * 
     * Takes two params: username and password
     *
     */
    public class BackgroundLoginTask extends AsyncTask<Object, String, Boolean>
    {       
       private Exception e = null;

       @Override
       protected void onPreExecute()
       {
           cont = Controller.getInstance();
           //Show progress dialog
           String pleaseWait = getResources().getString(R.string.pleaseWait);
           String commWithServer = getResources().getString(R.string.communicatingWithServer);
            if (pleaseWaitDialog == null)
              pleaseWaitDialog= ProgressDialog.show(NSFkioskLoginActivity.this, pleaseWait, commWithServer, true);

       }

        @Override
        protected Boolean doInBackground(Object... params)
        {
        try {
            //Returns true if credentials were valid. False if not. Exception if server could not be reached.
            return cont.validateCredentials((String)params[0], (String)params[1]);
        } catch (Exception e) {
            this.e=e;
            return false;
        }
        }

        /**
         * result is passed from doInBackground. Indicates whether credentials were validated.
         */
        @Override
        protected void onPostExecute(Boolean result)
        {
        //Hide progress dialog and handle exceptions
        //Progress dialog may be null if rotation has been switched
        if (pleaseWaitDialog != null)
             {
            pleaseWaitDialog.dismiss();
                pleaseWaitDialog = null;
             }

        if (e != null)
        {
         //Show toast with exception text
                String networkError = getResources().getString(R.string.serverErrorException);
                Toast toast = Toast.makeText(getApplicationContext(), networkError, Toast.LENGTH_SHORT);
            toast.show();
        }
        else
        {
            if (result == true)
            {
            saveCredentialsToPreferences(true);
            gotoMainMenu();
            }
            else
            {
            String toastText = getResources().getString(R.string.invalidCredentialsEntered);
                Toast toast = Toast.makeText(getApplicationContext(), toastText, Toast.LENGTH_SHORT);
            toast.show();
            } 
        }
        }

    }
}

我绝不是一个经验丰富的Android开发人员，所以请随意发表评论。

如果你创建了一个后台服务来完成所有繁重的工作(tcp请求/响应，解组)，视图和活动可以被销毁并重新创建，而不会泄漏窗口或丢失数据。这允许Android推荐的行为，即在每次配置更改时销毁一个Activity。对于每个方向变化)。

它有点复杂，但它是调用服务器请求、数据预处理/后处理等的最佳方式。

您甚至可以使用您的服务将每个请求排队到服务器，因此它使处理这些事情变得简单和高效。

开发指南有一个关于服务的完整章节。

我有一个实现，允许活动在屏幕方向改变上被销毁，但仍然在重新创建的活动中成功地销毁对话框。 我用…NonConfigurationInstance将后台任务附加到重新创建的活动。 正常的Android框架处理重新创建对话框本身，没有任何改变。

我子类化了AsyncTask，为“拥有”活动添加了一个字段，以及一个更新这个所有者的方法。

class MyBackgroundTask extends AsyncTask<...> {
  MyBackgroundTask (Activity a, ...) {
    super();
    this.ownerActivity = a;
  }

  public void attach(Activity a) {
    ownerActivity = a;
  }

  protected void onPostExecute(Integer result) {
    super.onPostExecute(result);
    ownerActivity.dismissDialog(DIALOG_PROGRESS);
  }

  ...
}

在我的活动类中，我添加了一个字段backgroundTask引用'owned' backgroundTask，我使用onRetainNonConfigurationInstance和getLastNonConfigurationInstance更新这个字段。

class MyActivity extends Activity {
  public void onCreate(Bundle savedInstanceState) {
    ...
    if (getLastNonConfigurationInstance() != null) {
      backgroundTask = (MyBackgroundTask) getLastNonConfigurationInstance();
      backgroundTask.attach(this);
    }
  }

  void startBackgroundTask() {
    backgroundTask = new MyBackgroundTask(this, ...);
    showDialog(DIALOG_PROGRESS);
    backgroundTask.execute(...);
  }

  public Object onRetainNonConfigurationInstance() {
    if (backgroundTask != null && backgroundTask.getStatus() != Status.FINISHED)
      return backgroundTask;
    return null;
  }
  ...
}

进一步改进建议:

在任务完成后，清除活动中的backgroundTask引用以释放与之关联的所有内存或其他资源。 在活动被销毁之前，清除后台任务中的ownerActivity引用，以防它不会立即被重新创建。 创建一个BackgroundTask接口和/或集合，以允许不同类型的任务从相同的活动中运行。

最简单和最灵活的解决方案是使用带有ProgressBar静态引用的AsyncTask。这为方向更改问题提供了一个封装的、因此可重用的解决方案。这个解决方案很好地帮助我完成了各种异步任务，包括互联网下载、与服务通信和文件系统扫描。该解决方案已经在多个安卓版本和手机型号上进行了良好的测试。完整的演示可以在DownloadFile.java中找到

下面是一个概念示例

public class SimpleAsync extends AsyncTask<String, Integer, String> {
    private static ProgressDialog mProgressDialog = null;
    private final Context mContext;

    public SimpleAsync(Context context) {
        mContext = context;
        if ( mProgressDialog != null ) {
            onPreExecute();
        }
    }

    @Override
    protected void onPreExecute() {
        mProgressDialog = new ProgressDialog( mContext );
        mProgressDialog.show();
    }

    @Override
    protected void onPostExecute(String result) {
        if ( mProgressDialog != null ) {
            mProgressDialog.dismiss();
            mProgressDialog = null;
        }
    }

    @Override
    protected void onProgressUpdate(Integer... progress) {
        mProgressDialog.setProgress( progress[0] );
    }

    @Override
    protected String doInBackground(String... sUrl) {
        // Do some work here
        publishProgress(1);
        return null;
    }

    public void dismiss() {
        if ( mProgressDialog != null ) {
            mProgressDialog.dismiss();
        }
    }
}

在Android Activity中的使用很简单

public class MainActivity extends Activity {
    DemoServiceClient mClient = null;
    DownloadFile mDownloadFile = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate( savedInstanceState );
        setContentView( R.layout.main );
        mDownloadFile = new DownloadFile( this );

        Button downloadButton = (Button) findViewById( R.id.download_file_button );
        downloadButton.setOnClickListener( new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mDownloadFile.execute( "http://www.textfiles.com/food/bakebred.txt");
            }
        });
    }

    @Override
    public void onPause() {
        super.onPause();
        mDownloadFile.dismiss();
    }
}