Instant value change handler on a GWT textbox

Question

I would like to update a text field instantly when typing in a GWT TextBox. My problem is that ValueChangeEvent and ChangeEvent handlers only fire when the TextBox loses foc

Answer 1

As a general solution, what works for me (thx to gal-bracha comment):

Generally, GWT does not have classes to handle input event (described here and here). So we need to implement it by ourselves:

Handler class:

import com.google.gwt.event.shared.EventHandler;

public interface InputHandler extends EventHandler {

  void onInput(InputEvent event);

}

Event class:

import com.google.gwt.event.dom.client.DomEvent;

public class InputEvent extends DomEvent {

    private static final Type TYPE = new Type("input", new InputEvent());

    public static Type getType() {
        return TYPE;
    }

    protected InputEvent() {
    }

    @Override
    public final Type getAssociatedType() {
        return TYPE;
    }

    @Override
    protected void dispatch(InputHandler handler) {
        handler.onInput(this);
    }

}

Usage:

box.addDomHandler(new InputHandler() {

    @Override
    public void onInput(InputEvent event) {
        text.setText(box.getText());
    }
},InputEvent.getType());

It works on every TextBox value change including pasting using context menu. It does not react on arrows, ctrl, shift etc...