not able to set focus on TextBox in a GWT app

Question

This should not be causing me so much pain but it is. It is a very weird problem. In a GWT application, I have two .java files, login.java and application.java. In login.java, I

Answer 1

Try using Scheduler.scheduleDeferred():

public void onModuleLoad() {
    Login login = new Login();
    Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand () {
        public void execute () {
            login.textBoxUsername.setFocus(true);
        }
    });
    RootLayoutPanel.get().add(login);       
}

Update: answer updated to use Scheduler.get().scheduleDeferred() instead of DeferredCommand, which is deprecated.

Answer 2

Why using DefferedCommand, I think it's better to use someWidget.getElement().focus() which is a native Javascript. I'm using it everywhere, I've not seen any problem.

Answer 3

It would be so easy for GWT to store a 'wantsFocus' in the internal state, and call focus after the widget is attached. We are still waiting after many years for that feature however...

Still, even after the attach handler is called, setFocus does not always work.

So in the meantime, our GwtUtil library has used the following code. It is a combination of several other solutions, and has been wrapped in a utility function:

static public void setFocus(final FocusWidget focusWidget) {
    if (focusWidget.isAttached()) {
        Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
            @Override
            public void execute() {
                focusWidget.setFocus(true);
            }
        });
    } else {
        focusWidget.addAttachHandler(new AttachEvent.Handler() {
            @Override
            public void onAttachOrDetach(AttachEvent event) {
                if (event.isAttached()) {
                    Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
                        @Override
                        public void execute() {
                            focusWidget.setFocus(true);
                        }
                    });
                }
            }
        });
    }
}

And call it like this:

setFocus(myTextBox);

It makes sense to use a utility function; If and when GWT finally makes setFocus work, you won't have to change your source code in multiple places.

Answer 4

If your Widget extends Composite, you can:

@Override
protected void onAttach() {
    super.onAttach();
    textBoxUsername.setFocus(true);
}