CODEWITHSUNDEEP
javafxcomboboxcontrols
Hervé Girod
Hervé Girod

Reputation: 527

How to force showing the popup part of a ComboBox in JavaFX

I want to be able to always show the popup part of a combobox regardless of the fact it has been clicked or not, or even without the combo being focused. I tried to use the show() method of the combo, but in my case the popup part never shows.

My code is:

import javafx.application.Platform;
import javafx.collections.ObservableList;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.layout.Pane;
import javafx.stage.Stage;

public class ComBoBoxTest {
   public static final void main(String[] args) {
      ComBoBoxTest test = new ComBoBoxTest();
      test.setup();
   }

   private void setup() {
      new JFXPanel();
      Platform.runLater(new Runnable() {
         @Override
         public void run() {
            createUI();
         }

      });
   }

   private void createUI() {
      Stage stage = new Stage();
      Pane pane = new Pane();
      ComboBox<String> combo = new ComboBox();
      ObservableList<String> values = combo.getItems();
      values.add("ONE");
      values.add("TWO");
      values.add("THREE"); 
      combo.setVisibleRowCount(3);
      combo.show();
      pane.getChildren().add(combo);
      Scene scene = new Scene(pane);
      stage.setScene(scene);
      stage.show(); // the important part
   }
}

In that case, I thought that my show() method would force to open the popup, but the result is that the popup is never shown

Upvotes: 0

Views: 272

Answers (1)

Herv&#233; Girod
Herv&#233; Girod

Reputation: 527

Per the excellent comment of kleopatra, the solution is to call show() on the Combo after the Stage is shown. This example works:

import javafx.application.Platform;
import javafx.collections.ObservableList;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.layout.Pane;
import javafx.stage.Stage;

public class ComBoBoxTest {
   public static final void main(String[] args) {
      ComBoBoxTest test = new ComBoBoxTest();
      test.setup();
   }

   private void setup() {
      new JFXPanel();
      Platform.runLater(new Runnable() {
         @Override
         public void run() {
            createUI();
         }

      });
   }

   private void createUI() {
      Stage stage = new Stage();
      Pane pane = new Pane();
      ComboBox<String> combo = new ComboBox();
      ObservableList<String> values = combo.getItems();
      values.add("ONE");
      values.add("TWO");
      values.add("THREE"); 
      combo.setVisibleRowCount(3);
      
      pane.getChildren().add(combo);
      Scene scene = new Scene(pane);
      stage.setScene(scene);
      stage.show(); 
      combo.show(); // call show() on the Combo after the stage is shown
   }
}

Upvotes: 2

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