Why ComboBox setValue do not work in Vaadin? - combobox

Question

I have simple code:
ComboBox<String> combo=new ComboBox<>("Combo");
Button button = new Button("Button");
button.addClickListener(new ComponentEventListener<ClickEvent<Button>>() {
#Override
public void onComponentEvent(ClickEvent<Button> event) {
combo.setItems("11","22");
combo.setValue("22");
}
});
When I first time click button i have items "11" and "22" present in combobox and value "22" is selected.
Second click makes value cleared but items "11" and "22" are still present.
In case I select "11" or leave "22" selected in combobox and click button - value clears.
It seems that setValue() only works when combobox is empty but following code do not helps as well:
combo.setValue(null);
combo.clear();
combo.setItems("11","22");
combo.setValue(null);
combo.clear();
combo.setValue("22");
Following code sets value of ComboBox correctly, no matter if I select some value or clear it before click:
ComboBox<String> combo=new ComboBox<>("Combo");
combo.setItems("11","22");
Button button = new Button("Button");
button.addClickListener(new ComponentEventListener<ClickEvent<Button>>() {
#Override
public void onComponentEvent(ClickEvent<Button> event) {
combo.setValue("22");
}
});
But I have to set items of Combobox dynamically and the last solution do not suitable for me.
Vaadin version is 10.0.9.
Has anyone some suggestions or advices ?
PS.
Thanks !
I've tried following code:
combo.setItems(Collections.emptyList());
combo.setItems("11","22");
combo.setValue("22");
But it do not work as well.
This code works only if value in combo is empty, but if I input something in combo the code just clears value by .setItems() and further .setValue() do not work.
If value of combo is empty the code works well.

Answer 1

Your code works perfectly fine in a minimum project based on https://vaadin.com/start/latest/project-base (which uses Vaadin 12.0.7)
#Route("")
#PWA(name = "Project Base for Vaadin Flow", shortName = "Project Base")
public class MainView extends VerticalLayout {
public MainView() {
ComboBox<String> combo=new ComboBox<>("Combo");
Button button = new Button("Button");
button.addClickListener(new ComponentEventListener<ClickEvent<Button>>() {
#Override
public void onComponentEvent(ClickEvent<Button> event) {
combo.setItems("11","22");
combo.setValue("22");
}
});
add(combo,button);
}
}
Whatever value you set in the ComboBox via UI .. when the button is clicked, the selected value will switch to 22.
If that's an option for you, you could update to a newer Vaadin version and try it with that.

Answer 2

To better show what I meant in my comment, I'm writing it as an answer.
What I meant was to set an empty collection not in the clickListener but directly after initializing the ComboBox:
ComboBox<String> combo=new ComboBox<>("Combo");
combo.setItems(Collections.emptyList());
Button button = new Button("Button");
button.addClickListener(new ComponentEventListener<ClickEvent<Button>>() {
#Override
public void onComponentEvent(ClickEvent<Button> event) {
combo.setItems("11","22");
combo.setValue("22");
}
});
please try it out and let me know if that works