[Urwid] ListBox loses focus

Martin Siebel lonequestor at yahoo.de
Thu Feb 9 05:55:04 EST 2012


Hello,

I am trying to build a GridBox widget, which is similiar to the GridFlow widget, but can be scrolled.

In doing so, I encountered a problem using urwid's ListBox when setting a focus explicitely.
The following code generates a display with 3x5 checkboxes. The focus is explicitely set on the second entry in the third row.
When running this code in a terminal which is large enough to hold the focus without scrolling the list, the focus is set to the first entry in the third row instead of the second.
When the terminal is small enough not to hold the focus without scrolling, the focus is set properly.

I could trace the problem back to the render method of the ListBox, which explicitely alters the focus of the contained Columns object.
(See the second code snippet and the corresponding output).

Is this a bug in the ListBox or am I doing something wrong when setting the focus?

Any help would be appreciated!
Best regards.


Snippet 1:

######################################################################################

#! /usr/bin/python                                                                                                                                                                                   
import urwid
import random

palette = [('header', 'white', 'dark red', "", "#afd", "#f0f"),
           ('footer', 'black', 'light blue', "", "#6f0", "#d00"),
           ('reveal focus', 'dark green', 'yellow', "", "#fd0", "#808"),
           ('body', 'yellow', 'dark green', 'standout', "#808", "#fd0"),
           ('edit', 'black', 'light gray', "", "#f0f", "#afd")]

buttons = [urwid.AttrMap(urwid.CheckBox(k), None, 'reveal focus')
           for k in ["%d %s" % (i, j)
                     for i, j in
                     enumerate(sorted(["".join([chr(random.randint(97, 122))
                                                for x in range(
                                                       random.randint(4, 16))])
                                       for j in range(15)]))]]
body = urwid.ListBox(urwid.SimpleListWalker([urwid.Columns(buttons[3*i:3*i+3])
                                             for i in range(len(buttons)/3)]))
body.set_focus(2)
body.get_focus()[0].set_focus(1)
loop = urwid.MainLoop(body, palette)
loop.screen.set_terminal_properties(colors=256)
loop.run()


Snippet 2:

########################################################################
#! /usr/bin/python                                                                                                                                                                                   
import urwid
import random
import sys
from math import log10
palette = [('header', 'white', 'dark red', "", "#afd", "#f0f"),
           ('footer', 'black', 'light blue', "", "#6f0", "#d00"),
           ('reveal focus', 'dark green', 'yellow', "", "#fd0", "#808"),
           ('body', 'yellow', 'dark green', 'standout', "#808", "#fd0"),
           ('edit', 'black', 'light gray', "", "#f0f", "#afd")]

def log(txt):
    import time
    f = open("/tmp/gridbox.log", "a")
    f.write("%s: %s\n" % (time.strftime("%H:%M:%S"), txt))
    f.close()

class MyListBox(urwid.ListBox):
    def __init__(self, *args, **kwargs):
        urwid.ListBox.__init__(self, *args, **kwargs)
    def render(self, *args, **kwargs):
        log("BEFORE RENDER:")
        for i in self.body:
            l = [j.original_widget for j in i.widget_list]
            log("row %d: [%s], focus is on %d" % (id(i),
                                                  ", ".join([str(id(j)) for j in l]),
                                                  i.get_focus_column()))

        retval = super(MyListBox, self).render(*args, **kwargs)
        log("AFTER RENDER:")
        for i in self.body:
            l = [j.base_widget for j in i.widget_list]
            log("row %d: [%s], focus is on %d" % (id(i),
                                                  ", ".join([str(id(j)) for j in l]),
                                                  i.get_focus_column()))

        return retval

buttons = [urwid.AttrMap(urwid.CheckBox(k), None, 'reveal focus')
           for k in ["%d %s" % (i, j)
                     for i, j in
                     enumerate(sorted(["".join([chr(random.randint(97, 122))
                                                for x in range(random.randint(4, 16))])
                                       for j in range(15)]))]]
body = MyListBox(urwid.SimpleListWalker([urwid.Columns(buttons[3*i:3*i+3])
                                         for i in range(len(buttons)/3)]))
body.set_focus(2)
body.get_focus()[0].set_focus(1)
loop = urwid.MainLoop(body, palette)
loop.screen.set_terminal_properties(colors=256)
loop.run()


Output of snippet 2:

11:51:44: BEFORE RENDER:
11:51:44: row 35364944: [35360976, 35361296, 35361552], focus is on 0
11:51:44: row 35365008: [35361808, 35362064, 35362320], focus is on 0
11:51:44: row 35365072: [35362576, 35362832, 35363088], focus is on 1
11:51:44: row 35365136: [35363344, 35363600, 35363856], focus is on 0
11:51:44: row 35365200: [35364112, 35364368, 35364624], focus is on 0
11:51:44: AFTER RENDER:
11:51:44: row 35364944: [35360976, 35361296, 35361552], focus is on 0
11:51:44: row 35365008: [35361808, 35362064, 35362320], focus is on 0
11:51:44: row 35365072: [35362576, 35362832, 35363088], focus is on 0
11:51:44: row 35365136: [35363344, 35363600, 35363856], focus is on 0
11:51:44: row 35365200: [35364112, 35364368, 35364624], focus is on 0
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