need help: insert item into listbox in thread

[zl03jsj]

Description:

I have a thread purpose to read some data, then insert the item with the data into a listbox,
but the listbox doesn't refresh automatically,
unless i press some key on the listbox. following is my code:

import threading
import time

import urwid


class OrderListBox(urwid.ListBox):
    def __init__(self, max_item_size=20):
        super(OrderListBox, self).__init__(urwid.SimpleListWalker([
            urwid.AttrMap(urwid.Text(
                '{} order content...'.format(0)), None, 'I say')
        ]))
        self.max_item_size = max_item_size
        self.idx: int = 1

    def insert(self):
        text = urwid.Text('{} order content...'.format(self.idx))
        wrap = urwid.AttrMap(text, None, 'I say')
        self.body.insert(0, wrap)
        self.idx = self.idx + 1
        if len(self.body) > self.max_item_size:
            self.body = self.body[:self.max_item_size]

    def keypress(self, size, key):
        key = super(OrderListBox, self).keypress(size, key)
        pass


list_box = OrderListBox()

palette = [('I say', 'default,bold', 'default'), ]
mainloop = urwid.MainLoop(list_box, palette)


def loop_insert():
    while True:
        list_box.insert()
        # mainloop.draw_screen()
        time.sleep(3)


loop_refresh_thread = threading.Thread(target=loop_insert, args=())
loop_refresh_thread.start()

mainloop.run()

mainloop.draw_screen() looks could force the whole screen to refresh,
but i don't known if it is the correct way, maybe there are some better approach to do this?

[danschwarz]

What version of Urwid are you running? This sounds a lot like the problem I'm experiencing with #575 , running against the latest master.

[penguinolog]

What version of Urwid are you running? This sounds a lot like the problem I'm experiencing with #575 , running against the latest master.

No, threading works correctly. Asyncio based code has issues

[penguinolog]

Correct way: _invalidate() modifies widget:

class OrderListBox(urwid.ListBox):
    def __init__(self, max_item_size=20):
        super().__init__(urwid.SimpleListWalker([
            urwid.AttrMap(urwid.Text(
                '{} order content...'.format(0)), None, 'I say')
        ]))
        self.max_item_size = max_item_size
        self.idx: int = 1

    def insert(self):
        text = urwid.Text('{} order content...'.format(self.idx))
        wrap = urwid.AttrMap(text, None, 'I say')
        self.body.insert(0, wrap)
        self.idx = self.idx + 1
        if len(self.body) > self.max_item_size:
            self.body = self.body[:self.max_item_size]
        self._invalidate()
        # this is the bottom-most widget, which was modified. All top-level widgets will be handled automatically

    def keypress(self, size, key):
        key = super().keypress(size, key)

[penguinolog]

Also you can connect callback to the SimpleListWalker instance, if you are not making some extra modifications after insert of items

[zl03jsj]

Correct way: _invalidate() modifies widget:

class OrderListBox(urwid.ListBox):
    def __init__(self, max_item_size=20):
        super().__init__(urwid.SimpleListWalker([
            urwid.AttrMap(urwid.Text(
                '{} order content...'.format(0)), None, 'I say')
        ]))
        self.max_item_size = max_item_size
        self.idx: int = 1

    def insert(self):
        text = urwid.Text('{} order content...'.format(self.idx))
        wrap = urwid.AttrMap(text, None, 'I say')
        self.body.insert(0, wrap)
        self.idx = self.idx + 1
        if len(self.body) > self.max_item_size:
            self.body = self.body[:self.max_item_size]
        self._invalidate()
        # this is the bottom-most widget, which was modified. All top-level widgets will be handled automatically

    def keypress(self, size, key):
        key = super().keypress(size, key)

thanks for your reply, it help me a lot.

[zl03jsj]

As @penguinolog has left the correct approach, i will close this issue.