【发布时间】：2018-03-25 22:34:28
【问题描述】：
我正在为我的应用程序创建一个小部件，但是当我必须填充列表视图时我被卡住了。我使用我在 WidgetDataProvider（实现 RemoteViewsService.RemoteViewsFactory）的 onCreate() 中调用的 asynctask 从我的 web db 中获取每个项目。 问题是，通常当我创建小部件时，它不会填充列表，我必须等待几秒钟才能在主屏幕中释放小部件。
如果我抓住并释放小部件，它会如下所示：empty widget
如果我等待，它会像这样显示：right widget
这是我的代码：
AppWidget
public class AppWidget extends AppWidgetProvider {
static void updateAppWidget(Context context, AppWidgetManager appWidgetManager, int appWidgetId) {
RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.app_widget);
Intent intent = new Intent(context, LoginActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);
views.setOnClickPendingIntent(R.id.widget_title, pendingIntent);
views.setRemoteAdapter(R.id.widget_listView, new Intent(context, WidgetService.class));
appWidgetManager.updateAppWidget(appWidgetId, views);
}
@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
super.onUpdate(context, appWidgetManager, appWidgetIds);
for (int appWidgetId : appWidgetIds) {
updateAppWidget(context, appWidgetManager, appWidgetId);
}
}
@Override
public void onEnabled(Context context) {
}
@Override
public void onDisabled(Context context) {
}
}
**WidgetService **
public class WidgetService extends RemoteViewsService {
@Override
public RemoteViewsFactory onGetViewFactory(Intent intent) {
return new WidgetDataRemote(this, intent);
}}
WidgetDataRemote
public class WidgetDataRemoteimplements RemoteViewsService.RemoteViewsFactory {
Context context;
Intent intent;
ArrayList<String> date = new ArrayList<>();
ArrayList<String> subj = new ArrayList<>();
ArrayList<String> type = new ArrayList<>();
ArrayList<String> comment = new ArrayList<>();
JSONParser jsonParser = new JSONParser();
ArrayList<String> subjFromDb = new ArrayList<>();
int pippo = 0;
public WidgetDataRemote(Context context, Intent intent) {
this.context = context;
this.intent = intent;
}
@Override
public RemoteViews getViewAt(int position) {
RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.item_widget);
remoteViews.setTextViewText(R.id.task_data, date.get(position));
remoteViews.setTextViewText(R.id.task_subject, subj.get(position));
remoteViews.setTextViewText(R.id.task_type, type.get(position));
remoteViews.setTextViewText(R.id.task_comment, comment.get(position));
return remoteViews;
}
@Override
public void onCreate() {
new LoadSubjects().execute();
}
@Override
public void onDataSetChanged() {
}
@Override
public void onDestroy() {
date.clear();
subj.clear();
type.clear();
comment.clear();
}
@Override
public int getCount() {
return date.size();
}
@Override
public RemoteViews getLoadingView() {
return null;
}
@Override
public int getViewTypeCount() {
return 1;
}
@Override
public long getItemId(int id) {
return id;
}
@Override
public boolean hasStableIds() {
return true;
}
class LoadSubjects extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
subjFromDb.clear();
pippo = 0;
}
@Override
protected String doInBackground(String... args) {
List<NameValuePair> params = new ArrayList<>();
params.add(new BasicNameValuePair("class", User.getClasse()));
JSONArray json = jsonParser.makeHttpRequestArray(Constants.URL_LOAD_SUBJECTS, "POST", params);
try {
if (!json.toString().equals("[null]")) {
for (int i = 0; i < json.length(); i++) {
JSONObject c = json.getJSONObject(i);
String subj = c.getString(Constants.TAG_NAME);
subjFromDb.add(subj);
}
} else {
pippo = 1;
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
if (pippo == 0) {
new LoadTasks().execute();
}
}
class LoadTasks extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pippo = 0;
}
@Override
protected String doInBackground(String... args) {
List<NameValuePair> params = new ArrayList<>();
params.add(new BasicNameValuePair("id_class", User.getClasse()));
JSONArray json = jsonParser.makeHttpRequestArray(Constants.URL_LOAD_TASKS, "POST", params);
try {
if (!json.toString().equals("[null]")) {
for (int i = 0; i < json.length(); i++) {
JSONObject c = json.getJSONObject(i);
Date data = null;
try {
data = new SimpleDateFormat("yyyy-MM-dd").parse(c.getString(Constants.TAG_DATE));
} catch (ParseException e) {
e.printStackTrace();
}
String newDate = new SimpleDateFormat("dd/MM/yyyy").format(data);
if (subjFromDb.contains(c.getString(Constants.TAG_SUBJECT))) {
date.add(newDate);
subj.add(c.getString(Constants.TAG_SUBJECT));
type.add(c.getString(Constants.TAG_TYPE));
comment.add(c.getString(Constants.TAG_COMMENT));
}
}
} else {
pippo = 1;
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
if (pippo == 0){
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
ComponentName thisWidget = new ComponentName(context, WidgetDataProvider.class);
int[] appWidgetIds = appWidgetManager.getAppWidgetIds(thisWidget);
appWidgetManager.notifyAppWidgetViewDataChanged(appWidgetIds, R.id.widget_listView);
// I use this to update the listview after fetch data. Is it correct?
}
}
}
}}
【问题讨论】：
标签： android listview android-asynctask widget