Access method from different screen controller

Support
#1

Hello,

I’m attempting to set a SideMenu badge after an entity has been committed. This will update the number of entries that need to be addressed. I’ve extended the Main Screen and created a service to get the data from the database, and all works perfectly upon loading the application. The problem I’m running into is after I commit a new entry, I receive a Null Pointer Exception trying to update the badge from there, but I can’t find what the issue is.

FlightBadgeCountServiceBean.java

package com.company.badgecount.service;

import com.company.badgecount.entity.Flight;
import com.haulmont.cuba.core.EntityManager;
import com.haulmont.cuba.core.Persistence;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.inject.Inject;
import java.util.List;

@Service(FlightBadgeCountService.NAME)
@Transactional
public class FlightBadgeCountServiceBean implements FlightBadgeCountService {
    @Inject
    private Persistence persistence;

    private static final String GET_FLIGHTS = "select e from badgecount_Flight e where e.flightAcknowledged is null or e.flightAcknowledged = :flightAcknowledged";

    public Integer getUnacknowledgedFlights() {
        EntityManager em = persistence.getEntityManager();

        List<Flight> result = em.createQuery(GET_FLIGHTS, Flight.class).setParameter("flightAcknowledged", false).getResultList();

        return result.size();
    }
}

ExtMainScreen.java

package com.company.badgecount.web.screens;

import com.company.badgecount.service.FlightBadgeCountService;
import com.haulmont.cuba.gui.components.mainwindow.SideMenu;
import com.haulmont.cuba.gui.screen.Subscribe;
import com.haulmont.cuba.gui.screen.UiController;
import com.haulmont.cuba.gui.screen.UiDescriptor;
import com.haulmont.cuba.web.app.main.MainScreen;

import javax.inject.Inject;

@UiController("extMainScreen")
@UiDescriptor("ext-main-screen.xml")
public class ExtMainScreen extends MainScreen {
    @Inject
    private SideMenu sideMenu;
    @Inject
    private FlightBadgeCountService flightBadgeCountService;

    @Subscribe
    public void onInit(InitEvent event) {
        updateFlightBadgeCount();
    }

    public void updateFlightBadgeCount() {
        Integer flightCount = flightBadgeCountService.getUnacknowledgedFlights();

        if (flightCount != null && flightCount > 0) {
            sideMenu.getMenuItem("flightMenuItem").setBadgeText(flightCount.toString());
        }
    }



}

FlightEdit.java

package com.company.badgecount.web.screens.flight;

import com.company.badgecount.web.screens.ExtMainScreen;
import com.haulmont.cuba.gui.screen.*;
import com.company.badgecount.entity.Flight;

@UiController("badgecount_Flight.edit")
@UiDescriptor("flight-edit.xml")
@EditedEntityContainer("flightDc")
@LoadDataBeforeShow
public class FlightEdit extends StandardEditor<Flight> {

    @Subscribe
    public void onAfterCommitChanges(AfterCommitChangesEvent event) {
        ExtMainScreen extMainScreen = new ExtMainScreen();
        extMainScreen.updateFlightBadgeCount();
    }


}

So the problem seems to stem from the FlightEdit.java class in the onAfterCommitChanges event. Am I simply calling the ExtMainScreen controller incorrectly in this area? Is there a different way to accomplish this?

I’d love an idea of what I’m doing incorrectly.

Thanks,
Adam

#2

I also referenced the following forum post, but I wasn’t able to get this working either.

#3

Hi,

Please provide full exception stack trace. It is essential to understand the cause of your problem.

#4

You cannot create screens like this, just by calling constructor.
If you are opening the screen, use Screens API to get instance of the screen controller:
https://doc.cuba-platform.com/manual-7.2/opening_screens.html

#5

Well, I’m not really trying to create a new screen, but rather just trying to access the SideMenu that exists in the ext-main-screen.xml descriptor. I’m just trying to update the badge in this file once a Flight instance has been saved.

I created the service to do this because I needed a way to access the database to check the total count of Flights that qualify to be listed as the badge number. I don’t know of a good way to access the SideMenu outside of the ExtMainScreen.java controller.

However…

I found a solution from the PetClinic demo by creating a timer facet in the ext-main-screen.xml descriptor.

<facets>
    <timer id="refreshFlights" delay="3000" autostart="true" repeating="true"/>
</facets>

And then in the controller…

@Subscribe("refreshFlights")
public void onRefreshFlightsTimerAction(Timer.TimerActionEvent event) {
    updateFlightBadgeCount();
}

Thanks!
Adam

#6

OK, the optimal recommended way to call logic from one screen to another is to use custom UI event.

  • create your own event class
  • throw event in FlightEdit
  • process event in ExtMainScreen

Examples here:
https://doc.cuba-platform.com/manual-7.2/events.html#ui_events

https://www.cuba-platform.com/guides/decouple-business-logic-with-app-events#cuba_ui_events