如何使用 DialogFragment 显示 AsyncTask 的进度 - 不使用 ProgressDialog

Question

这个网站已经帮助了我一年了，这是我第一次找不到问题的答案。

我正在尝试从没有 ProgressDialog 的 AsyncTask 发布进度。用户只需输入一个地址，我想在地图和列表中显示该地址一定半径范围内的名胜古迹。因此，我需要从数据库中获取这些地方的地址并计算距离，然后才能知道我需要在地图上显示哪些地方作为标记。

在计算距离（在 AsyncTask 中）时，我想在标记最终显示在地图上之前让用户了解进度。

我的代码主要有两个问题：

• 它会正确显示和关闭 DialogFragment，但不会显示进度（既不按栏，也不按数字）
• 我不想使用 ProgressDialog

非常感谢任何提示或建议！

我的 AsyncTask 看起来像这样：

public class GetDistanceTask extends AsyncTask<Void,Integer,Integer>
{

private Location mSearchAddress;
private FragmentManager mSfm;
private ContentResolver mCr;
private static final String TAG = GetDistanceTask.class.getSimpleName();
private DialogFragment mDf;
private ProgressDialog mProgressDialog;

public GetDistanceTask(FragmentManager sfm, ContentResolver cr, Location searchAddress){
    mSfm = sfm;
    mCr = cr;
    mSearchAddress = searchAddress;
}

@Override
protected Integer doInBackground(Void...voids) {
    int rowsUpdated = 0;
    int max = 0;
    final Uri locationUri = KitaContract.LocationEntry.CONTENT_URI;
    String selection = KitaProvider.sLocationKitaSelection;
    String[] args = new String[] {"3"};
    //All entries, unsorted
    Cursor cursor = mCr.query(locationUri, null, selection, args, null);
    if (cursor != null) {
        max = cursor.getCount();
        cursor.moveToFirst();
    } else {
        Log.e(TAG, "Cursor == null !");
        return 0;
    }
        do{
            double kitaLat = cursor.getDouble(COL_LAT);
            double kitaLong = cursor.getDouble(COL_LONG);
            int id = cursor.getInt(COL_LOCID);

            //make a Location-object from Kita's Lat & Long
            Location kitaAddress = new Location("kitaName");
            kitaAddress.setLatitude(kitaLat);
            kitaAddress.setLongitude(kitaLong);
            //calculate distance
            float distance = kitaAddress.distanceTo(mSearchAddress);
            ContentValues contentValues = new ContentValues();
            contentValues.put(KitaContract.LocationEntry.COLUMN_DIST, distance);

            //add the distance to the kita entry in the database
            int rowUpdated =mCr.update(
                    locationUri,
                    contentValues,
                    KitaContract.LocationEntry._ID + " = ?",
                    new String[] {String.valueOf(id)});
            rowsUpdated += rowUpdated;
            publishProgress(rowsUpdated, max);
        }while (cursor.moveToNext());
    cursor.close();


    return rowsUpdated;
}

@Override
protected void onPreExecute() {
    super.onPreExecute();
    // instantiate ProgressDialog
    mDf = (DistanceProgressDialogFragment) mSfm.findFragmentByTag("dpdf_tag");
    if (mDf == null){
        mDf = new DistanceProgressDialogFragment();
        mSfm.beginTransaction()
                .add(mDf, "dpdf_tag")
                .commitAllowingStateLoss();
    }
    else mDf.show(mSfm, "dpdf_tag");

    if (mDf != null) {
        mProgressDialog = (ProgressDialog) mDf.getDialog();
        mProgressDialog.setProgressNumberFormat("%1d/%2d Kitas");
    }
}

@Override
protected void onProgressUpdate(Integer... progress) {
    mProgressDialog.setMax(progress[1]);
    mProgressDialog.setProgress(progress[0]);
    super.onProgressUpdate(progress);
}

@Override
protected void onPostExecute(Integer rowsUpdated) {
    if ( mDf != null) {
        mDf.dismiss();
    }
}

我的 DialogFragment 是这样的：

public class DistanceProgressDialogFragment extends DialogFragment
{

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setCancelable(false);
}



@NonNull
@Override
public ProgressDialog onCreateDialog(Bundle savedInstanceState)
{
    ProgressDialog dialog = new ProgressDialog(getActivity(), getTheme());
    dialog.setTitle("Kita Guide");
    dialog.setMessage("Suche Kitas in der Nähe");
    dialog.setIndeterminate(true);
    dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    return dialog;
}
}

Answer 1

dialog.setIndeterminate(true); 表示进度条应该永远保持 运行。