A button widget connected to a simple callback function.
In line 16 the "clicked" signal from the button is connected to the callback function do_clicked() using widget.connect(signal, callback function). See for a more detailed explanation.
set_relief(Gtk.ReliefStyle.NONE) sets to none the relief style of the edges of the Gtk.Button - as opposed to Gtk.ReliefStyle.NORMAL.
If the label of the button is a stock icon, set_use_stock(True) sets the label as the name of the corresponding stock icon.
To set an image (e.g. a stock image) for the button button:
image = Gtk.Image()
image.set_from_stock(Gtk.STOCK_ABOUT, Gtk.IconSize.BUTTON)
button.set_image(image)
You should not set a label for the button after this, otherwise it will show the label and not the image.
If we use set_focus_on_click(False) the button will not grab focus when it is clicked by the mouse. This could be useful in places like toolbars, so that the keyboard focus is not removed from the main area of the application.
In this sample we used the following:
GtkButton
GtkWindow