JavaFX Get ComboBox from ChoiceDialog

Question

I have a javafx.scene.control.ChoiceDialog object in my JavaFX project. When the dialog opens, I want to set the focus to the underlying ComboBox. However, I can't figure out how to get the underlying ComboBox control. With a TextInputDialog, there is a method called getEditor(). Is there any way (other than reflectively accessing the private comboBox member) to get the underlying ComboBox?

Answer 1

To set the focus to the ComboBox you can use a dirty hack, which triggers updateGrid of the ChoiceDialog after it is shown:

ChoiceDialog<String> choiceDialog = new ChoiceDialog<>("test", getData());
choiceDialog.showingProperty().addListener((ov, b, b1) -> {
    if (b1) {
        choiceDialog.setContentText("");
    }else {
        choiceDialog.setContentText(null);
    }

    //or 
    if (b1) {
        Node comboBox = choiceDialog.getDialogPane().lookup(".combo-box");
        comboBox.requestFocus();
    }
});

---

Obtaining the ComboBox instance using the style class is useful to override the default keyboard navigation:

final var options = (ComboBox) getDialogPane().lookup( ".combo-box" );
options.setOnKeyPressed( ( event ) -> {
  // When the user presses the down arrow, open the drop-down. This prevents
  // navigating to the cancel button.
  if( event.getCode() == KeyCode.DOWN && !options.isShowing() ) {
    options.show();
    event.consume();
  }
} );

When the above changes in place, pressing the down arrow key will open the combo box instance instead of navigating to the Cancel button.