Python GTK 3.0：在次要线程中访问GUI是否不被支持？

Question

Python GTK 3.0：在次要线程中访问GUI是否不被支持？

3

我基于Python Gtk3开发了一个GUI程序。在主窗口中有一个按钮和一个进度条，我的目的是当按下按钮时，另一个线程会运行以完成一些工作，最终另一个GTK窗口会显示结果，同时进度条可以正确地更新主窗口中的进度。但是我总是遇到以下错误：

[xcb] Unknown sequence number while processing queue
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
python: xcb_io.c:274: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.
Aborted (core dumped)

我真的不知道出了什么问题，也没有任何想法，有人能帮忙看一下并提供一个例子吗？

非常感谢！

我在这里开发了一个测试程序，但在Linux平台下总是遇到以下错误：

(fileChooser.py: 40834)：Gtk-CRITICAL **：gtk_text_attributes_ref：断言'values！= NULL'失败

(fileChooser.py: 40834)：Pango-CRITICAL **：pango_layout_new：断言'context！= NULL'失败分段错误（核心已转储）

#!/usr/bin/env python

import os
import re
import multiprocessing
import threading
import platform
from gi.repository import Gtk, GLib, Gdk, GObject

class ANA(Gtk.Window):
    def __init__(self):
        Gtk.Window.__init__(self)                                                                                                                                                              
        self.tree_store = dict()
        self.COL_NAME = 0 
        self.COL_COLOR = 1 

        self.window = Gtk.Window()
        self.window.set_title("Analysing Results")
        self.window.set_size_request(1000, 750)
        self.connect('destroy', lambda *w: Gtk.main_quit())

        self.main_vbox = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=1)
        self.window.add(self.main_vbox)

        self.hpaned = Gtk.HPaned()
        self.hpaned.set_position(295)
        self.main_vbox.pack_start(self.hpaned, True, True, 0)

        self.notebook = Gtk.Notebook()
        for tab in ['A', 'B']:
            scrolled_window = Gtk.ScrolledWindow()
            scrolled_window.set_policy(Gtk.PolicyType.AUTOMATIC, Gtk.PolicyType.AUTOMATIC)
            scrolled_window.set_shadow_type(Gtk.ShadowType.IN)

            self._new_notebook_page(self.notebook, scrolled_window, tab)

            treeview = self.__create_treeview(tab)
            scrolled_window.add(treeview)

        self.hpaned.add(self.notebook)

        self.notebook1 = Gtk.Notebook()
        self.hpaned.add(self.notebook1)
    
        self.scrolled_window2, self.info_buffer, self.info_text_view = self.__create_text(True)
        self._new_notebook_page(self.notebook1, self.scrolled_window2, '_Info')

        info_text_view = self.info_text_view

        self.window.show_all()

    def _new_notebook_page(self, notebook, widget, label):
        l = Gtk.Label(label='')
        l.set_text_with_mnemonic(label)
        notebook.append_page(widget, l)

    def __create_text(self, is_source=False):
        scrolled_window = Gtk.ScrolledWindow()
        scrolled_window.set_policy(Gtk.PolicyType.AUTOMATIC, Gtk.PolicyType.AUTOMATIC)
        scrolled_window.set_shadow_type(Gtk.ShadowType.IN)

        text_view = Gtk.TextView()
        scrolled_window.add(text_view)

        buffer = Gtk.TextBuffer()
        text_view.set_buffer(buffer)
        text_view.set_editable(False)
        text_view.set_cursor_visible(True)

        return scrolled_window, buffer, text_view
        
    def __create_treeview(self, tab_name):
        treestore = Gtk.TreeStore(str, str)
        self.tree_store[tab_name] = treestore
        treeview = Gtk.TreeView(treestore)
        selection = treeview.get_selection()
        selection.set_mode(Gtk.SelectionMode.BROWSE)
        treeview.set_size_request(200, -1) 

        cell = Gtk.CellRendererText()
        column = Gtk.TreeViewColumn(tab_name, cell, foreground=self.COL_COLOR)
        column.add_attribute(cell, "text", self.COL_NAME)

        treeview.append_column(column)

        if tab_name == "A":
            selection.connect('changed', self.selection_changed_A)
        elif tab_name == "B":
            selection.connect('changed', self.selection_changed_B)

        treeview.expand_all()
        return treeview

    def selection_changed_A(self):
        print "A" 

    def selection_changed_B(self):
        print "B" 

class ANALYSING_PROCESS(multiprocessing.Process):
    def __init__(self):
        super(ANALYSING_PROCESS, self).__init__()

    def run(self):
        import time
        time.sleep(5)
        ANA()

class ANALYSING_THREAD(threading.Thread):
    def __init__(self, pbar, timer):
        super(ANALYSING_THREAD, self).__init__()
        self.pbar = pbar
        self.timer = timer

    def run(self):
        Gdk.threads_init()
        Gdk.threads_enter()
        import time
        time.sleep(5)
        ANA()
        Gdk.threads_leave()

        self.pbar.set_text("Done")
        self.pbar.set_show_text(True)
        GObject.source_remove(self.timer)

class File_Chooser(Gtk.Window):
    def __init__(self):
        Gtk.Window.__init__(self)
        self.connect('destroy', lambda *w: Gtk.main_quit())

        self.set_title("Test")
        self.set_border_width(8)

        frame = Gtk.Frame()
        self.add(frame)

        self.vbox = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=8)
        self.vbox.set_border_width(8)
        frame.add(self.vbox)

        label = Gtk.Label()
        label.set_markup("<span font_desc=\"Serif 25\" foreground=\"#015F85\" size=\"x-large\"> Test</span>")
        self.vbox.pack_start(label, False, False, 0)

        self.button_entry = dict()
        self.entry_name = dict()

        hbox = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL, spacing=8)

        button = Gtk.Button("Browse Files")
        button.connect('clicked', self.browse_files)
        hbox.pack_start(button, False, False, 0)

        label = Gtk.Label()
        label.set_markup("<span foreground=\"#015F85\"> files </span>")
        label.set_use_underline(True)
        hbox.pack_start(label, False, False, 0)

        self.entry1 = Gtk.Entry()
        hbox.pack_start(self.entry1, True, True, 0)
        label.set_mnemonic_widget(self.entry1)
        self.button_entry[button] = self.entry1
        self.entry_name['files'] = self.entry1

        self.vbox.pack_start(hbox, False, False, 0)

        separator = Gtk.HSeparator()
        self.vbox.pack_start(separator, False, False, 1)

        alignment1 = Gtk.Alignment()
        alignment1.set_halign(Gtk.Align.CENTER)
        self.vbox.pack_start(alignment1, False, False, 1)

        self.pbar = Gtk.ProgressBar()
        alignment1.add(self.pbar)
        self.pbar.set_text("Not Run")
        self.pbar.set_show_text(True)


        hbox2 = Gtk.HBox(False, 2)
        self.vbox.pack_start(hbox2, False, False, 1)

        button3 = Gtk.Button("Analyze")
        button3.connect('clicked', self.tar_File_analyze)
        hbox2.pack_end(button3, False, False, 1)

        button4 = Gtk.Button("close")
        button4.connect('clicked', self.__quit)
        hbox2.pack_end(button4, False, False, 1)

        self.show_all()

    def browse_files(self, button):
        dialog = Gtk.FileChooserDialog("Please choose a file", self,
            Gtk.FileChooserAction.OPEN,
            (Gtk.STOCK_CANCEL, Gtk.ResponseType.CANCEL,
             Gtk.STOCK_OPEN, Gtk.ResponseType.OK))

        filter = Gtk.FileFilter()
        filter.set_name("Tar files")
        filter.add_pattern("*.tar")
        filter.add_pattern("*.rar")
        filter.add_pattern("*.tar.gz")
        dialog.add_filter(filter)

        filter = Gtk.FileFilter()
        filter.set_name("All files")
        filter.add_pattern("*")
        dialog.add_filter(filter)

        filter = Gtk.FileFilter()
        filter.set_name("Images")
        filter.add_mime_type("image/png")
        filter.add_mime_type("image/jpeg")
        filter.add_mime_type("image/gif")
        filter.add_pattern("*.png")
        filter.add_pattern("*.jpg")
        filter.add_pattern("*.gif")
        filter.add_pattern("*.tif")
        filter.add_pattern("*.xpm")
        dialog.add_filter(filter)

        response = dialog.run()
        if response == Gtk.ResponseType.OK:
            print dialog.get_filename(), 'selected'
            self.button_entry[button].set_text(dialog.get_filename())
            #entry.set_text(dialog.get_filename())
        elif response == Gtk.ResponseType.CANCEL:
            print 'Closed, no files selected'
        dialog.destroy()

    def tar_File_analyze(self, button):
            
        #PROGRESS_THREAD(self.pbar).start()
        self.pbar.set_text("Running")
        self.pbar.set_show_text(True)
        ####self.timer = GObject.timeout_add (100, self.progress_timeout, self)
        self.timer = GLib.timeout_add(100, self.progress_timeout)
            
        t = ANALYSING_THREAD(self.pbar, self.timer)
        #t = ANALYSING_PROCESS()
        t.start()

    def progress_timeout(self):
        self.pbar.pulse()
        return True

    def warning(self, warnings):
        dialog = Gtk.MessageDialog(self, 0, Gtk.MessageType.WARNING,
                Gtk.ButtonsType.OK, "Warning!")
        dialog.format_secondary_text(warnings)

        response = dialog.run()
        if response == Gtk.ResponseType.OK:
            dialog.destroy()

    def __quit(self, button):
        self.destroy()

    def run(self):
        Gtk.main()

def main():
    File_Chooser().run()

if __name__ == '__main__':
    main()

有人能看一下吗？这是关于IT技术的问题。

- bluezd

请包含产生错误的示例代码。 - Dan D.

你看过这里吗：https://wiki.gnome.org/Projects/PyGObject/Threading？这描述了从另一个线程访问主循环的规范方式。话虽如此，我自己在使用Gtk和多线程时遇到了问题，因为我错过了某个idle_add，但我从未遇到过这样的xcb失败。所以，不确定它是否与Gtk有关，也许是代码的另一部分。 - Cilyan

我之前检查过了，但还是不起作用。 - bluezd

@DanD。我添加了示例代码，你能帮忙看一下吗？谢谢！ - bluezd

@DanD. 这里有什么意见吗？ - bluezd

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Roland Smith · Accepted Answer

一般来说，GUI工具包不支持多线程进行工具包调用。通常只有初始线程被允许这样做。使GUI工具包真正线程安全是一个难题，这是一种避免的方式。

一种可能的解决方案是让主线程使用空闲函数或定时器回调来检查工作线程中的进度。

另一种解决方案是将工作放在外部进程而不是线程中进行。这有许多优点：

它使通信明确且可追踪。GUI工具包通常可以监视文件描述符或套接字，通过超时或空闲回调处理其中的信息。
保持GUI单线程使锁定大部分不必要。
在CPython上，它实际上可以利用多核机器，从而规避GIL。