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");
      }
  }
}

这是我提出的解决方案:

Move the AsyncTask or Thread to a retained Fragment, as explained here. I believe it is a good practice to move all network calls to fragments. If you are already using fragments, one of them could be made responsible for the calls. Otherwise, you can create a fragment just for doing the request, as the linked article proposes. The fragment will use a listener interface to signal the task completion/failure. You don't have to worry for orientation changes there. The fragment will always have the correct link to the current activity and progress dialog can be safely resumed. Make your progress dialog a member of your class. In fact you should do that for all dialogs. In the onPause method you should dismiss them, otherwise you will leak a window on the configuration change. The busy state should be kept by the fragment. When the fragment is attached to the activity, you can bring up the progress dialog again, if the call is still running. A void showProgressDialog() method can be added to the fragment-activity listener interface for this purpose.

当你切换方向时，Android会创建一个新的View。你可能会崩溃，因为你的后台线程试图改变旧线程的状态。(它也可能有麻烦，因为你的后台线程不在UI线程上)

我建议将mHandler设为volatile，并在方向改变时更新它。

If you're struggling with detecting orientation change events of a dialog INDEPENDENT OF AN ACTIVITY REFERENCE, this method works excitingly well. I use this because I have my own dialog class that can be shown in multiple different Activities so I don't always know which Activity it's being shown in. With this method you don't need to change the AndroidManifest, worry about Activity references, and you don't need a custom dialog (as I have). You do need, however, a custom content view so you can detect the orientation changes using that particular view. Here's my example:

设置

public class MyContentView extends View{
    public MyContentView(Context context){
        super(context);
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig){
        super.onConfigurationChanged(newConfig);

        //DO SOMETHING HERE!! :D
    }
}

实现1 -对话

Dialog dialog = new Dialog(context);
//set up dialog
dialog.setContentView(new MyContentView(context));
dialog.show();

实现2 - AlertDialog。构建器

AlertDialog.Builder builder = new AlertDialog.Builder(context);
//set up dialog builder
builder.setView(new MyContentView(context));        //Can use this method
builder.setCustomTitle(new MycontentView(context)); // or this method
builder.build().show();

实现3 - ProgressDialog / AlertDialog

ProgressDialog progress = new ProgressDialog(context);
//set up progress dialog
progress.setView(new MyContentView(context));        //Can use this method
progress.setCustomTitle(new MyContentView(context)); // or this method
progress.show();

将长任务移动到单独的类中。将其实现为主题-观察者模式。每当创建活动时，注册并在关闭时注销任务类。任务类可以使用AsyncTask。

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();
    }
}