pygtk和多处理-从运行无限循环的另一个进程不断更新textview

Question

我正在用pygtk构建一个python应用程序。它由一些用于激活/停用一些无限循环过程的按钮和一个文本视图组成，该文本视图应不断显示每个​​过程中发生的事情。像冗长的东西。

这些过程还没有结束。仅当用户单击相应按钮（或关闭应用程序）时，它们才会停止。

出了什么问题：我无法通过这些过程在textview中打印内容。也许是因为他们还没有结束...

实际上，该应用太大，无法在此处显示整个代码。所以我做了一个简单的小例子来说明我在做什么。

import pygtk
pygtk.require("2.0")
import gtk
import time
import glib
from multiprocessing import Process
gtk.threads_init()

class Test(gtk.Window):
    def delete_event(self, widget, event, data=None):
        if isinstance(self.my_process, Process):
            if self.my_process.is_alive():
                self.my_process.terminate()
        gtk.main_quit()
        return False

    def __init__(self):

        gtk.Window.__init__(self)
        self.set_default_size(500, 400)
        self.set_title(u"Test")
        self.connect("delete_event", self.delete_event)

        self.mainBox = gtk.VBox(False, 5)

        self.text = gtk.TextView()
        self.text.set_wrap_mode(gtk.WRAP_WORD)
        self.button = gtk.Button("Start")

        self.add(self.mainBox)
        self.mainBox.pack_start(self.text, True, True, 0)
        self.mainBox.pack_start(self.button, False, True, 0)

        self.button.connect("clicked", self.start_clicked)

        self.show_all()

    def start_clicked(self, widget):
        self.register_data("Starting...")
        self.my_process = Process(target=self.do_something)
        self.my_process.start()

    def do_something(self):
        while True:
            time.sleep(0.5)
            #get a list of a lot of things
            #Do stuff with each item in the list
            #show me on the gui whats going on
            glib.idle_add(self.register_data, "Yo! Here I'm")
            print "Hello, boy."

    def register_data(self, data):
        data = data + "\r\n"
        #gtk.gdk.threads_enter()
        buff = self.text.get_buffer()
        biter = buff.get_start_iter()
        buff.insert(biter, data)
        #gtk.gdk.threads_leave()


if __name__ == "__main__":
    mnc = Test()
    mnc.set_position(gtk.WIN_POS_CENTER)
    gtk.threads_enter()
    gtk.main()
    gtk.threads_leave()

Answer 1

删除所有.threads_init()，.threads_enter()，.threads_leave()。multiprocessing不是threading。

将您想要显示的数据放入multiprocessing.Queue()子进程中：

def do_something(self):
    while True:
        #get a list of a lot of things
        #Do stuff with each item in the list
        #show me on the gui whats going on
        self.data_queue.put("Yo! Here I'm")

并在GUI循环中对其进行轮询：

def __init__(self, ...):
    # ...
    self.data_queue = Queue()
    gobject.timeout_add(100, self.update_text) 

哪里：

def update_text(self):
    # receive updates from the child process here
    try:
        data = self.data_queue.get_nowait()
    except Empty:
        pass # nothing at this time
    else:
        self.register_data(data)
    return True

为了避免轮询，您可以multiprocessing.Pipe在子进程中进行写入，并使用来设置GUI回调gobject.io_add_watch()。这是完整的代码示例：

#!/usr/bin/python3
from multiprocessing import Pipe, Process
import gi
gi.require_version('Gtk', '3.0')
from gi.repository import GObject, Gtk

# create GUI to show multiprocessing output
win = Gtk.Window()
win.set_default_size(640, 480)
label = Gtk.Label('process output')
win.add(label)

# start dummy infinite loop in a child process
def loop(conn):
    import itertools, sys, time
    for i in itertools.count():
        conn.send(i)
        time.sleep(0.1 - time.monotonic() % 0.1)

parent_conn, child_conn = Pipe(duplex=False)
Process(target=loop, args=[child_conn], daemon=True).start()
child_conn.close()

# read values from the child
def read_data(source, condition):
    assert parent_conn.poll()
    try:
        i = parent_conn.recv()
    except EOFError:
        return False # stop reading
    # update text
    label.set_text('Result from the child: %03d' % (i,))
    return True # continue reading
# . configure the callback
GObject.io_add_watch(parent_conn.fileno(), GObject.IO_IN, read_data)

win.connect('delete-event', Gtk.main_quit)
win.show_all()
Gtk.main()

您还可以使用任意子进程（不仅仅是python子进程）来执行此操作。