[gtkmm-4.0] how to check if a Gtk::Entry has focus

[lanfust]

I use gtkmm-4.0 on ubuntu 22.04 LTS.

For example create 2 entries and test them if they are focused with is_focus() or has_focus(). It always answer false even if i use grab_focus().
If i test another focus widget it answers true.

So how to check and know which entry is used by a user ?

[StefanSalewski]

Better describe what you really intend, not what you do. I have no idea why someone may want to query focus for a widget. For your task, maybe Gtk.Widget.get_state_flags would help, I played with that function myself recently. But maybe what you desire is just connecting to a signal?

[lanfust]

Thanks for your answer.

For example you have many entries, user set text in an entry.
How to know in which entry the user is typing text?

[StefanSalewski]

Generally we connect to the “activate” or the “changed” signal for a GtkEntry. “activate” is emitted, when the user pressed RETURN or another meta key, changed is emited for every keystroke. Most of the time “activate” is what we want – if the user is done with his input, we get the new string. I can not tell you how you connect to signals in gtkmm, I have used only C, Python, Ruby, Nim. But you should find that in the gtkmm tutorials, or just ask here again.

[lb90]

With GTK4 it’s best to use the following method to determine whether a widget has focus:

bool
util_widget_is_focused (const Gtk::Widget& widget)
{
  const Gtk::Root *root = widget.get_root ();
  if (!root)
    return false;

  const Gtk::Widget *focused = root->get_focus ();
  if (!focused)
    return false;

  return focused->is_ancestor (widget);
}

NOTE: not sure if an overload of Gtk::Widget::is_ancestor() taking a const reference as an argument exists. If you find issues, remove all the const qualifiers from the sample above.

[StefanSalewski]

@lb90

With GTK4 it’s best

That is an interesting idea. But I have the strong feeling, that the initial poster just is new to GTK and has to learn how one connect widget signals to callback functions.

[lanfust]

lb90
Thanks
Exactly what i need.
You are right don’t use const because of

error: binding reference of type ‘Gtk::Widget&’ to ‘const Gtk::Widget’ discards qualifiers
60 | return focused->is_ancestor(widget);