Python Gtk: How to get blink a row in a Treeview

I have a button and I want that the selected row blinks. Someone should click the blink button and then click event to_blinkstart a Thread _blink which change the values of the 3-6 str elements at MyTreeStore.

import threading
import time

class MyTreeStore(Gtk.TreeStore):
    def __init__(self):
        # i use the 3 last str's for the background colors
        Gtk.TreeStore.__init__(self, str, str, str, str, str, str)

 class TestBox(Gtk.VBox):
     def __init__(self): 

        self.treestore = MyTreeStore()
        self.treeview = Gtk.TreeView()
        self.treeview.set_model(self.treestore)

        renderer_col1 = Gtk.CellRendererText()
        column_1 = Gtk.TreeViewColumn("Col1", renderer_col1, text=0, cell_background=3)

        ...

        self.blink_button = Gtk.Button('Blink')
        self.is_connected_button.connect('clicked', self.to_blink)

   def to_blink(self, button):
    """ take certain row, start thread which change background-color """
       tree_selection = self.treeview.get_selection()
       tree_model, treepath = tree_selection.get_selected()

       if treepath:
           tree_model[treepath][3] = "green"
           tree_model[treepath][4] = "green"
           tree_model[treepath][5] = "green"

           t = threading.Thread(target=self._blink, args=(tree_model[treepath],))
           t.daemon = True
           t.start()

   def _blink(self, path):

       for i in range(100):
           path[3] = "green"
           path[4] = "green"
           path[5] = "green"
           time.sleep(1)
           path[3] = "white"
           path[4] = "white"
           path[5] = "white"

Solution

You should avoid threading as much as possible when working with GTK. In this case this could be solved with GLib.timeout_add instead.

Replace:

        t = threading.Thread(target=self._blink, args=(tree_model[treepath],))
        t.daemon = True
        t.start()

With:

        GLib.timeout_add(1000, self._blink_glib, tree_model[treepath])

    def _blink_glib(self, path):
        for i in range(3, 6):
            if path[i] == "white":
                path[i] = "green"
            else:
                path[i] = "white"
        return True

The callback needs to return True to keep going or False to stop. So you still have to implement a flag to indicate if the 100 iterations are done.

Just another note: if all columns will blink in the same colour it's not needed to create three extra treestore items, just one would suffice and point all three columns' cell_background to that item.

        column_1 = Gtk.TreeViewColumn("Col1", renderer_col1, text=0, cell_background=3)
        column_2 = Gtk.TreeViewColumn("Col2", renderer_col2, text=0, cell_background=3)
        column_3 = Gtk.TreeViewColumn("Col3", renderer_col3, text=0, cell_background=3)

    def _blink_glib(self, path):
        path[3] = "green" if path[3] == "white" else "white"
        return True