在长时间运行的过程中阻止pygtk GUI锁定

Question

我有一个过程需要一段时间(可能一两分钟)才能完成.当我从pygtk GUI调用此窗口时,窗口会在大约10秒后锁定(变暗并阻止用户操作).

我想阻止这种情况发生,但我不确定如何.我认为多线程将是答案,但似乎并没有起作用.我尝试了两种在网上找到的不同方法.首先,我修改了这个常见问题解答,以便进行长时间运行.其次我尝试使用threading.Thread直接像在这个答案,但也锁定.

我的两个样本如下.我是多线程的新手,所以也许这不是我正在寻找的解决方案.我基本上只是试图阻止GUI锁定,所以我可以使用进度条更新并让用户使用取消按钮.

#Sample 1
import threading
import time
import gobject
import gtk

gobject.threads_init()

class MyThread(threading.Thread):
    def __init__(self, label, button):
        super(MyThread, self).__init__()
        self.label = label
        self.button = button
        self.counter = 0
        button.connect("clicked", self.on_button_click)
        self.quit = False

    def update_label(self, counter):
        self.label.set_text("Counter: %i" % counter)
        time.sleep(20)
        return False

    def on_button_click(self, widget):
        self.counter += 1
        gobject.idle_add(self.update_label, self.counter)

window = gtk.Window()
label = gtk.Label()
box = gtk.VBox()
button = gtk.Button("Test")
box.pack_start(label)
box.pack_start(button)
window.add(box)
window.show_all()
window.connect("destroy", lambda _: gtk.main_quit())
thread = MyThread(label, button)
thread.start()

gtk.main()
thread.quit = True

#####################################
#Sample 2

from threading import Thread
import time
import gobject
import gtk

class Test():
    def __init__(self):
        self.counter = 0
        self.label = gtk.Label()
        button = gtk.Button("Test")

        window = gtk.Window()
        box = gtk.VBox()
        box.pack_start(self.label)
        box.pack_start(button)
        window.add(box)

        window.connect("destroy", lambda _: gtk.main_quit())
        button.connect("clicked", self.on_button_click)
        window.show_all()

    def update_label(self, counter):
        self.label.set_text("Counter: %i" % counter)
        time.sleep(20)
        return False

    def on_button_click(self, widget):
        self.counter += 1
        thread = Thread(target=self.update_label, args=(self.counter,))
        thread.start()
        while thread.is_alive():
            pass
        thread.stop()

test = Test()
gtk.main()

Answer 1

请在下面找到适用于我的第二个示例的修改版本:

import threading
import time
import gtk, gobject, glib

gobject.threads_init()

class Test():
    def __init__(self):
        self.counter = 0
        self.label = gtk.Label()
        self.progress_bar = gtk.ProgressBar()
        self.progress_bar_lock = threading.Lock()
        button = gtk.Button("Test")

        window = gtk.Window()

        box = gtk.VBox()
        box.pack_start(self.label)
        box.pack_start(self.progress_bar)
        box.pack_start(button)
        window.add(box)

        window.connect("destroy", lambda _: gtk.main_quit())
        button.connect("clicked", self.on_button_click)
        window.show_all()

    def update_label(self, counter):
        self.label.set_text("Thread started (counter: {0})"
                            .format(counter))
        time.sleep(5)
        self.label.set_text("Thread finished (counter: {0})"
                            .format(counter))
        return False

    def pulse_progress_bar(self):
        print threading.active_count()
        if threading.active_count() > 1:
            self.progress_bar.pulse()
            return True

        self.progress_bar.set_fraction(0.0)
        self.progress_bar_lock.release()
        return False

    def on_button_click(self, widget):
        self.counter += 1
        thread = threading.Thread(target=self.update_label,
                                  args=(self.counter,))
        thread.start()

        if self.progress_bar_lock.acquire(False):
            glib.timeout_add(250, self.pulse_progress_bar)


if __name__ == '__main__':
    test = Test()
    gtk.main()

所做的更改是:

• 避免在回调中等待线程完成以保持主循环处理事件.
• 添加了进度条,以便在执行线程时显示.
• 用于glib.timeout_add计划在执行某个线程时脉冲进度条的回调.这与轮询线程具有相同的效果,但具有主循环仍然响应其他事件的优点.
• 用于threading.Lock防止回调被安排多次,无论单击按钮多少次.
• 添加gobject.threads_init了此示例中缺少的内容(不在上一个示例中).

现在,当单击按钮时,只要线程正在运行,您就会看到如何点击标签并且进度条会发出脉冲.