我尝试使用以下代码编写一个放在主屏幕上的小部件：
this.userObservable = this.db.getUserAsObjectObservable() as FirebaseObjectObservable<any>;
this.userObservable.subscribe(data => console.log('Observable', data));
但是小部件在文本视图中显示时没有数据。
package com.example.anirudh.chatter;
import android.app.PendingIntent;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.widget.ArrayAdapter;
import android.widget.RemoteViews;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
/**
* Implementation of App Widget functionality.
*/
public class NewAppWidget extends AppWidgetProvider {
void updateAppWidget(Context context, AppWidgetManager appWidgetManager,
int appWidgetId) {
RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.new_app_widget);
views.setTextViewText(R.id.tv1, "hello");
System.out.print("abcdef");
Intent intent = new Intent(context, NewAppWidget.class);
intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
intent.setAction("update");
//This pending intent will run the intent created above
PendingIntent pi = PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
views.setOnClickPendingIntent(R.id.btnRefresh, pi);
new MyAsyncTask().execute(context);
// Instruct the widget manager to update the widget
appWidgetManager.updateAppWidget(appWidgetId, views);
}
@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
// There may be multiple widgets active, so update all of them
for (int appWidgetId : appWidgetIds) {
updateAppWidget(context, appWidgetManager, appWidgetId);
}
}
@Override
public void onReceive(Context context, Intent intent) {
super.onReceive(context, intent);
if (intent.getAction().equals("update")) {
new MyAsyncTask().execute(context);
System.out.print("abcdef");
}
}
@Override
public void onEnabled(Context context) {
// Enter relevant functionality for when the first widget is created
}
@Override
public void onDisabled(Context context) {
// Enter relevant functionality for when the last widget is disabled
}
class MyAsyncTask extends AsyncTask<Context, Void, ArrayList<String>> {
ArrayList<String> links = new ArrayList<>();
Context context;
RemoteViews views;
@Override
protected ArrayList<String> doInBackground(Context... params) {
context = params[0];
ArrayList<String> headlines = new ArrayList<>();
try {
URL url = new URL("http://www.codingconnect.net/feed");
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
factory.setNamespaceAware(false);
XmlPullParser xpp = factory.newPullParser();
// We will get the XML from an input stream
xpp.setInput(getInputStream(url), "UTF_8");
boolean insideItem = false;
// Returns the type of current event: START_TAG, END_TAG, etc..
int eventType = xpp.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT) {
if (eventType == XmlPullParser.START_TAG) {
if (xpp.getName().equalsIgnoreCase("item")) {
insideItem = true;
} else if (xpp.getName().equalsIgnoreCase("title")) {
if (insideItem)
headlines.add(xpp.nextText()); //extract the headline
} else if (xpp.getName().equalsIgnoreCase("link")) {
if (insideItem)
links.add(xpp.nextText()); //extract the link of article
}
} else if (eventType == XmlPullParser.END_TAG && xpp.getName().equalsIgnoreCase("item")) {
insideItem = false;
}
eventType = xpp.next(); //move to next element
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (XmlPullParserException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
System.out.print("heads:" + headlines);
return headlines;
}
protected void onPostExecute(ArrayList<String> heads) {
views = new RemoteViews(context.getPackageName(), R.layout.new_app_widget);
views.setTextViewText(R.id.tv1, " ");
views.setTextViewText(R.id.tv2, " ");
views.setTextViewText(R.id.tv3, " ");
views.setTextViewText(R.id.tv4, " ");
views.setTextViewText(R.id.tv5, " ");
if (heads != null && heads.size() >= 5) {
views.setTextViewText(R.id.tv1, heads.get(0));
views.setTextViewText(R.id.tv2, heads.get(1));
views.setTextViewText(R.id.tv3, heads.get(2));
views.setTextViewText(R.id.tv4, heads.get(3));
views.setTextViewText(R.id.tv5, heads.get(4));
}
}
public InputStream getInputStream(URL url) {
try {
return url.openConnection().getInputStream();
} catch (IOException e) {
return null;
}
}
}
}
方法永远不会被调用， Asynctask 也是如此，它用于必须放在文本视图中的rss-feed标题。
有人知道我的代码中有什么问题吗？