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。

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();
    }
}

我的解决方案是扩展ProgressDialog类来获得我自己的MyProgressDialog。

我重新定义了show()和dismiss()方法来在显示对话框之前锁定方向，并在对话框被解散时将其解锁。

因此，当显示对话框并且设备的方向发生变化时，屏幕的方向保持不变，直到调用dismiss()，然后屏幕方向根据传感器值/设备方向发生变化。

这是我的代码:

public class MyProgressDialog extends ProgressDialog {
    private Context mContext;

    public MyProgressDialog(Context context) {
        super(context);
        mContext = context;
    }

    public MyProgressDialog(Context context, int theme) {
        super(context, theme);
        mContext = context;
    }
    
    public void show() {
        if (mContext.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT)
            ((Activity) mContext).setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        else
            ((Activity) mContext).setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        super.show();
    }
    
    public void dismiss() {
        super.dismiss();
        ((Activity) mContext).setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);
    }
}

看起来太“快速和肮脏”了，所以请指出缺点，但我发现有用的是……

在我的AsyncTask的onPostExecute方法中，我简单地包装了`。try/catch块中的进度对话框(带有空捕获)的Dismiss '，然后简单地忽略所引发的异常。似乎是错误的，但似乎没有不良影响(至少对于我随后所做的事情，这是启动另一个活动，将我的长时间运行查询的结果传递为一个额外)

编辑:谷歌工程师不推荐这种方法，正如Dianne Hackborn(又名hackbod)在StackOverflow的帖子中所描述的那样。查看这篇博客文章了解更多信息。

你必须把这个添加到manifest中的activity声明中:

android:configChanges="orientation|screenSize"

看起来是这样的

<activity android:label="@string/app_name" 
        android:configChanges="orientation|screenSize|keyboardHidden" 
        android:name=".your.package">

问题是，当配置发生更改时，系统将破坏活动。看到ConfigurationChanges。

所以把它放在配置文件中可以避免系统破坏你的活动。相反，它调用onConfigurationChanged(Configuration)方法。

这是我面对这个问题时的解决方案: ProgressDialog不是一个Fragment子，所以我的自定义类“ProgressDialogFragment”可以扩展DialogFragment，以保持对话框显示的配置更改。

import androidx.annotation.NonNull;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.os.Bundle; 
import androidx.fragment.app.DialogFragment;
import androidx.fragment.app.FragmentManager;

 /**
 * Usage:
 * To display the dialog:
 *     >>> ProgressDialogFragment.showProgressDialogFragment(
 *              getSupportFragmentManager(), 
 *              "fragment_tag", 
 *              "my dialog title", 
 *              "my dialog message");
 *              
 * To hide the dialog
 *     >>> ProgressDialogFragment.hideProgressDialogFragment();
 */ 


public class ProgressDialogFragment extends DialogFragment {

    private static String sTitle, sMessage;
    private static ProgressDialogFragment sProgressDialogFragment;

    public ProgressDialogFragment() {
    }

    private ProgressDialogFragment(String title, String message) {
        sTitle = title;
        sMessage = message;
    }


    @NonNull
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        return ProgressDialog.show(getActivity(), sTitle, sMessage);
    }

    public static void showProgressDialogFragment(FragmentManager fragmentManager, String fragmentTag, String title, String message) {
        if (sProgressDialogFragment == null) {
            sProgressDialogFragment = new ProgressDialogFragment(title, message);
            sProgressDialogFragment.show(fragmentManager, fragmentTag);

        } else { // case of config change (device rotation)
            sProgressDialogFragment = (ProgressDialogFragment) fragmentManager.findFragmentByTag(fragmentTag); // sProgressDialogFragment will try to survive its state on configuration as much as it can, but when calling .dismiss() it returns NPE, so we have to reset it on each config change
            sTitle = title;
            sMessage = message;
        }

    }

    public static void hideProgressDialogFragment() {
        if (sProgressDialogFragment != null) {
            sProgressDialogFragment.dismiss();
        }
    }
}

我们面临的挑战是在屏幕上保留对话框标题和消息 当它们重置为默认空字符串时旋转，尽管对话框仍然显示

有两种方法可以解决这个问题:

第一种方法: 使利用对话框的活动在manifest文件中的配置更改期间保留状态:

android:configChanges="orientation|screenSize|keyboardHidden"

谷歌不喜欢此方法。

第二种方法: 在活动的onCreate()方法上，如果savedInstanceState不为空，你需要通过重新构建ProgressDialogFragment来保留你的对话片段。

@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_deal);

 if (savedInstanceState != null) {
      ProgressDialogFragment saveProgressDialog = (ProgressDialogFragment) getSupportFragmentManager()
              .findFragmentByTag("fragment_tag");
      if (saveProgressDialog != null) {
          showProgressDialogFragment(getSupportFragmentManager(), "fragment_tag", "my dialog title", "my dialog message");
      }
  }
}