有时我会在下面的活动中收到此错误，有时不会：
The content of the adapter has changed
but ListView did not receive a notification. Make sure the content of
your adapter is not modified from a background thread, but only from the
UI thread.
但我不确定我在下面班级的错误在哪里。有人知道吗？
public class FavoriteActivity extends SpeakSuperActivity {
private final static String TAG = FavoriteActivity.class.getSimpleName();
private Button btn_filter_topic, btn_filter_rating, btn_filter_none;
private TextView fav_filter_text;
private static ListView listViewFavorites;
private static TextView txtNoFavoritesYet;
private List<Favorite> currentFavorites;
private ArrayAdapter<Favorite> currentFavoritesArrayAdapter;
// required for list loading piece by piece
final int itemsPerLoading = Configuration.LOADED_ITEMS_ON_LIST_AT_ONCE;
boolean loadingMore = false;
private List<Long> idList;
int currentDataLoaded;
private static int oldBtnViewId = 0;
// set the start value as same as the loading value
int maximumDataLoadedYet = Configuration.LOADED_ITEMS_ON_LIST_AT_ONCE;
// 0 = not sorted, 1 = sorted by topic and minimum number of stars
private int caseSelection = 0;
private static View progressView;
private View footerView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.favorites);
Log.d(TAG, "FavoritesScreen onCreate()...");
// indicator for waiting processes
progressView = UIUtils.addBlockingProgressIndicatorBlack(this);
// init Listview
listViewFavorites = (ListView) findViewById(R.id.fav_listview_favorites);
// add the footer before adding the adapter, else the footer
// will not load!
footerView = ((LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.listviewfooter, null, false);
listViewFavorites.addFooterView(footerView);
listViewFavorites = (ListView) findViewById(R.id.fav_listview_favorites);
fav_filter_text = (TextView) findViewById(R.id.fav_filter_text);
btn_filter_none = (Button) findViewById(R.id.btn_fav_filter_none);
btn_filter_topic = (Button) findViewById(R.id.btn_fav_filter_topic);
btn_filter_rating = (Button) findViewById(R.id.btn_fav_filter_rating);
toggleButtonStates(R.id.btn_fav_filter_none);
LoadDataTask ldTask = new LoadDataTask();
ldTask.execute();
// no favorites yet?
txtNoFavoritesYet = (TextView) findViewById(R.id.fav_no_favorites_yet);
updateUI();
}
/**
* An asynchronous Task (doesn't block the UI Thread) for loading the Data in background.
*
* @author Jonas Soukup
*/
private class LoadDataTask extends AsyncTask<Void, Void, LoudmouthException> {
private final String TAG = LoadDataTask.class.getName();
protected void onPreExecute() {
super.onPreExecute();
if (FavoriteProvider.getInstance().getNumOfFavorites() != 0)
progressView.setVisibility(View.VISIBLE);
else
progressView.setVisibility(View.GONE);
listViewFavorites.setVisibility(View.GONE);
fav_filter_text.setVisibility(View.GONE);
btn_filter_none.setVisibility(View.GONE);
btn_filter_topic.setVisibility(View.GONE);
btn_filter_rating.setVisibility(View.GONE);
}
protected LoudmouthException doInBackground(Void... params) {
LoudmouthException exception = null;
Log.d(TAG, "loading data..");
switch (caseSelection) {
case 0:
// Get FavoriteList without sorting
idList = FavoriteProvider.getInstance().getFavoritesByDate();
break;
case 1:
// Get FavoriteList sorted by
// Topics + amount of stars
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
float minRating = prefs.getFloat(getResources().getString(R.string.rating_filter_star_amount), 0);
idList = FavoriteProvider.getInstance().getFavoritesByTopicAndMinRating(minRating);
break;
default:
Log.e(TAG, "No Case with number: " + caseSelection);
}
// reset data loaded, so it loads till maximumDataLoadedYet on a
// refresh of the list
currentDataLoaded = 0;
// reset List on Data change
currentFavorites = new ArrayList<Favorite>();
Log.d(TAG, "..loading data finished");
return exception;
}
protected void onPostExecute(LoudmouthException result) {
try {
Log.d(TAG, "LoadDataTask.onPostExecute()");
super.onPostExecute(result);
progressView.setVisibility(View.GONE);
if (result != null) {
// Error ocurred during loading
android.content.DialogInterface.OnClickListener retryClickListener = new android.content.DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
new LoadDataTask().execute();
}
};
UIUtils.showRetryCancelAlertDialog(getApplicationContext(), result, retryClickListener, null);
} else {
// Everythings fine, data loaded
// showing & hiding
if (FavoriteProvider.getInstance().getNumOfFavorites() == 0) {
fav_filter_text.setVisibility(View.GONE);
btn_filter_none.setVisibility(View.GONE);
btn_filter_topic.setVisibility(View.GONE);
btn_filter_rating.setVisibility(View.GONE);
} else {
fav_filter_text.setVisibility(View.VISIBLE);
btn_filter_none.setVisibility(View.VISIBLE);
btn_filter_topic.setVisibility(View.VISIBLE);
btn_filter_rating.setVisibility(View.VISIBLE);
}
if (idList.size() == 0) {
txtNoFavoritesYet.setVisibility(View.VISIBLE);
listViewFavorites.setVisibility(View.GONE);
} else {
txtNoFavoritesYet.setVisibility(View.GONE);
listViewFavorites.setVisibility(View.VISIBLE);
runOnUiThread(new Runnable() {
public void run() {
btn_filter_none.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
caseSelection = 0;
FavoriteProvider.getInstance().setCurrentFavoriteListStateDirty(true);
toggleButtonStates(v.getId());
updateUI();
}
});
btn_filter_topic.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
caseSelection = 1;
TopicFilterFavDialog tfFavDialog = new TopicFilterFavDialog(FavoriteActivity.this, FavoriteActivity.this, v
.getId());
tfFavDialog.show();
}
});
btn_filter_rating.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
caseSelection = 1;
RatingFilterFavDialog ratDialog = new RatingFilterFavDialog(FavoriteActivity.this, FavoriteActivity.this, v
.getId());
ratDialog.show();
}
});
}
});
}
}
// init listview displaying with data loaded step by step
currentFavoritesArrayAdapter = new FavoriteArrayAdapter(FavoriteActivity.this, FavoriteActivity.this, R.layout.favorite_list_entry,
currentFavorites);
listViewFavorites.setAdapter(currentFavoritesArrayAdapter);
currentFavoritesArrayAdapter.notifyDataSetChanged();
} catch (Exception exception) {
// silent catch because activity could be closed meanwhile
Log.i(TAG, "silent exception catch in onPostExecute: " + exception.getMessage());
}
}
}
/**
* Update UI
*/
public void updateUI() {
LoadDataTask ldTask = new LoadDataTask();
ldTask.execute();
if (currentFavoritesArrayAdapter != null)
currentFavoritesArrayAdapter.notifyDataSetChanged();
}
@Override
protected void onResume() {
super.onResume();
updateUI();
}
private class ListMoreItemsTask extends AsyncTask<Void, Void, LoudmouthException> {
@Override
protected LoudmouthException doInBackground(Void... arg0) {
LoudmouthException exception = null;
loadingMore = true;
// reset loading values if adapter was reseted
if (currentFavoritesArrayAdapter.getCount() == 0)
maximumDataLoadedYet = Configuration.LOADED_ITEMS_ON_LIST_AT_ONCE;
// Get value of Configuration.LOADEDITEMSONLISTATONCE new listitems
for (; currentDataLoaded < maximumDataLoadedYet && currentDataLoaded < idList.size(); currentDataLoaded++) {
// Fill the list with new information
currentFavorites.add(FavoriteProvider.getInstance().getFavorite(idList.get(currentDataLoaded)));
}
maximumDataLoadedYet += itemsPerLoading;
// Done loading more.
loadingMore = false;
return exception;
}
protected void onPostExecute(LoudmouthException result) {
if (result == null) {
// Tell to the adapter that changes have been made, this will
// cause
// the list to refresh
currentFavoritesArrayAdapter.notifyDataSetChanged();
// remove loading view when maximum data is reached
if (currentFavorites.size() == idList.size()) {
listViewFavorites.removeFooterView(footerView);
}
}
}
}
public void toggleButtonStates(int viewId) {
// set clicked button as selected
if (viewId != 0) {
switch (viewId) {
case R.id.btn_fav_filter_none:
btn_filter_none.setCompoundDrawablesWithIntrinsicBounds(getResources().getDrawable(R.drawable.filter_neuste_selected), null, null,
null);
btn_filter_none.setTextColor(getResources().getColor(color.black));
break;
case R.id.btn_fav_filter_topic:
btn_filter_topic.setCompoundDrawablesWithIntrinsicBounds(getResources().getDrawable(R.drawable.filter_themen_selected), null, null,
null);
btn_filter_topic.setTextColor(getResources().getColor(color.black));
break;
case R.id.btn_fav_filter_rating:
btn_filter_rating.setCompoundDrawablesWithIntrinsicBounds(getResources().getDrawable(R.drawable.filter_rating_selected), null, null,
null);
btn_filter_rating.setTextColor(getResources().getColor(color.black));
break;
default:
Log.d("TAG", "No View with id: " + viewId);
}
}
// if previews Button exists and wasn't the same button set the old
// one
// to selected false
if (oldBtnViewId != 0 && oldBtnViewId != viewId) {
// set clicked button as not selected
switch (oldBtnViewId) {
case R.id.btn_fav_filter_none:
btn_filter_none.setCompoundDrawablesWithIntrinsicBounds(getResources().getDrawable(R.drawable.filter_neuste), null, null, null);
btn_filter_none.setTextColor(getResources().getColor(R.color.font_grey));
break;
case R.id.btn_fav_filter_topic:
btn_filter_topic.setCompoundDrawablesWithIntrinsicBounds(getResources().getDrawable(R.drawable.filter_themen), null, null, null);
btn_filter_topic.setTextColor(getResources().getColor(R.color.font_grey));
break;
case R.id.btn_fav_filter_rating:
btn_filter_rating.setCompoundDrawablesWithIntrinsicBounds(getResources().getDrawable(R.drawable.filter_rating), null, null, null);
btn_filter_rating.setTextColor(getResources().getColor(R.color.font_grey));
break;
default:
Log.d("TAG", "No View with id: " + viewId);
}
}
oldBtnViewId = viewId;
}
}