get data from database in android widget

Question

i've created a class for my widget that should get data from the database of my app, but i have issues getting the data...here is my class

public class AppWidget extends AppWidgetProvider {
private static DBAdapter mDbHelper;
@Override
public void onReceive(Context ctxt, Intent intent)
{
    if(intent.getAction()==null)
    {
        ctxt.startService(new Intent (ctxt,ToggleService.class));
    }
    else
    {
        super.onReceive(ctxt,intent);
    }

}
@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds)
{

    context.startService(new Intent(context,ToggleService.class));
}

public static void updateWidgetContent(Context context,
    AppWidgetManager appWidgetManager, int[] appWidgetIds) {

}
private static DBAdapter getDatabaseHelper(Context context) {
    DBAdapter dbh = null;
    if (dbh == null) {
        dbh = new DBAdapter(context);
        dbh.open();
    }
    return dbh;
}
public static class ToggleService extends IntentService
{
    public ToggleService()
    {
        super("AppWidget$ToggleService");
    }

    @Override
    protected void onHandleIntent(Intent intent)
    {
        ComponentName me= new ComponentName(this,AppWidget.class);
        AppWidgetManager mgr= AppWidgetManager.getInstance(this);
        mgr.updateAppWidget(me,buildUpdate(this));
    }

    private RemoteViews buildUpdate(Context context)
    {
        RemoteViews updateViews= new RemoteViews(context.getPackageName(),R.layout.widget);


        Calendar c = Calendar.getInstance();
        SimpleDateFormat dateFormat= new SimpleDateFormat("yyyyMMdd");
        String dateForButton= dateFormat.format(c.getTime());
        Cursor ce= mDbHelper.fetchReminder(Integer.parseInt(dateForButton));
        ce.moveToFirst();
        //startManagingCursor(ce);

        updateViews.setTextViewText(R.id.dd,ce.getString(ce.getColumnIndexOrThrow(DBAdapter.KEY_de)));
        updateViews.setTextViewText(R.id.tt,"test2");
        updateViews.setTextViewText(R.id.ss,"test1");
        Intent i= new Intent(this, AppWidget.class);
        PendingIntent pi=  PendingIntent.getBroadcast(context, 0, i, 0);
        updateViews.setOnClickPendingIntent(R.id.kr, pi);
        return updateViews;

    }
}
 }

in the manifest everything is as it should, i have created the receiver and a service and before i added the line with the cursor the widget showed on the home screen but now with the cursor code included it crashes the app throwing null point exception on IntentService

Answer 1

what i see as error is that you should write this line of code

      mDbHelper=getDatabaseHelper(this);

before

   Cursor ce= mDbHelper.fetchReminder(Integer.parseInt(dateForButton));

because you have already defined the method getDatabaseHelper

Answer 2

The problem should be that u are using mDbHelper before instantiation.

I suggest you to initialize first your Adapter as follow:

private static DBAdapter getDatabaseHelper(Context context) {

    if (mDbHelper == null) {
        mDbHelper = new DBAdapter(context);
        mDbHelper.open();
    }
    return mDbHelper;
}

If this won't resolve your problem, please post your LogCat