Problem with ScrolledWindow

[krzmaciek]

Hello! I am using GTK-3 with Vala. In my app when button is clicked then new child is added to Box which is inside ScrolledWindow. I want ScrolledWindow to be scrolled to the bottom when such a thing happens. I tried to use ResizeMode.IMMEDIATE and it worked well (else it just scrolled to the bottom minus added element size) but it is deprecated. What is correct way of doing that?

[lb90]

You can get the scrolled window vadjustment and set its value. Look into gtk_scrolled_window_get_vadjustment and gtk_adjustment_set_value. According to the docs you should set the adjustment value to upper - page-size:

static void
scroll_to_bottom (GtkWidget *scrolled_window)
{
  GtkAdjustment *adjustment = gtk_scrolled_window_get_vadjustment (GTK_SCROLLED_WINDOW (scrolled_window));
  double upper = gtk_adjustment_get_upper (adjustment);
  double page_size = gtk_adjustment_get_page_size (adjustment);
  gtk_adjustment_set_value (adjustment, upper - page_size);
}

[chimpa_theist]

Also, to the “scrolled to bottom minus element size”, you can do.

create a callback to “changed” signal of the GtkAdjustment. This signal is emmited when some attribute different from ‘value’ is changed. Eg. It is emmited when ‘page_size’ changes.

So, all we need to do is to get the ‘upper’ attribute from the GtkAdjustment and set the ‘value’ attribute to this value (or to ‘upper’ - ‘page_size’, if you prefer).

Doing this, the scroll will be on the bottom of the Scrolled Window.