在 PyGTK 中按下按钮后如何更新菜单？

Question

我对 PyGTK 不太熟悉。请看下面的代码。是否可以让它执行以下操作？

1. 有两个按钮，我们称之为“生成”和“查看”。
2. “生成”按钮将为变量 A 和 B 生成随机值。
3. “查看”按钮将弹出一个显示 A 和 B 的菜单。

以下代码的问题是“查看”菜单显示 A 和 B，但当用户按下“生成”按钮时，菜单不会更新。

我使用 Python 2.6.6 运行代码。

还请建议我改进代码的任何方法（格式、样式、PyGTK 约定，...）。先感谢您。

   """Generate values for two variables A and B."""
# ------------------------------------------------------------------------------
# Winston C. Yang
# Created 2010-12-04
# ------------------------------------------------------------------------------
# Python modules. Be alphabetical.
import random
# ------------------------------------------------------------------------------
# Other Python modules. Be alphabetical.
import gtk
import pygtk
pygtk.require("2.0")
# ------------------------------------------------------------------------------
class Generator:

    """Generate values for two variables A and B."""

    def __init__(self):

        # Create a dictionary in which a key is a variable name and a
        # (dictionary) value is the variable value.
        self.d_variable_value = {}
        # ----------------------------------------------------------------------
        window = gtk.Window()
        window.set_title("Generate")
        window.connect("destroy", self.quit_event)
        # ----------------------------------------------------------------------
        # Create a vertical box with two buttons.
        vbox = gtk.VBox()

        # Create a button to generate values for A and B.
        b = gtk.Button("Generate A and B")
        vbox.pack_start(b)
        b.connect("clicked", self.generate_variable_values)

        # Create a button to view A and B.
        b = gtk.Button("View A and B")
        vbox.pack_start(b)
        b.connect_object("event", self.button_press, self.create_menu())
        # ----------------------------------------------------------------------
        window.add(vbox)
        window.show_all()
    # --------------------------------------------------------------------------
    def quit_event(self, widget=None, event=None):
        """Quit."""
        gtk.main_quit()
    # --------------------------------------------------------------------------
    def generate_variable_values(self, widget=None):
        """Generate values for A and B."""
        self.d_variable_value = {
            "A" : random.randint(0, 10),
            "B" : random.randint(0, 10),
            }

        print "I generated " + str(self.d_variable_value)
    # --------------------------------------------------------------------------
    def button_press(self, widget, event):
        """button_press method."""
        if event.type == gtk.gdk.BUTTON_PRESS:
            widget.popup(None, None, None, event.button, event.time)
            return True

        return False
    # --------------------------------------------------------------------------
    def create_menu(self):
        """Create a menu showing A and B."""
        # How can I update the menu after the user presses the
        # "generate" button?

        # If there are no values for A and B, generate them.
        if not self.d_variable_value:
            self.generate_variable_values()

        # Show A and B in a menu.
        menu = gtk.Menu()

        for key, value in sorted(self.d_variable_value.items()):

            text = key + " " + str(value)
            item = gtk.MenuItem(text)
            item.show()
            menu.append(item)

        return menu
# ------------------------------------------------------------------------------
if __name__ == "__main__":
    Generator()
    gtk.main()

Answer 1

此行 b.connect_object("event", self.button_press, self.create_menu()) 将 self.button_press 连接到 event 信号在由 self.create_menu() 创建的 gtk.Menu 上。该行永远不会再次执行，因此菜单始终相同。

我所做的是将 View A 和 B 按钮的 event 信号连接到 self.button_press 处理程序，并且该处理程序创建一个更新的菜单每次运行时。

# ------------------------------------------------------------------------------
# Python modules. Be alphabetical.
import random
# ------------------------------------------------------------------------------
# Other Python modules. Be alphabetical.
import gtk
import pygtk
pygtk.require("2.0")
# ------------------------------------------------------------------------------
class Generator:

    """Generate values for two variables A and B."""

    def __init__(self):

        # Create a dictionary in which a key is a variable name and a
        # (dictionary) value is the variable value.
        self.d_variable_value = {}
        # ----------------------------------------------------------------------
        window = gtk.Window()
        window.set_title("Generate")
        window.connect("destroy", self.quit_event)
        # ----------------------------------------------------------------------
        # Create a vertical box with two buttons.
        vbox = gtk.VBox()

        # Create a button to generate values for A and B.
        b = gtk.Button("Generate A and B")
        vbox.pack_start(b)
        b.connect("clicked", self.generate_variable_values)

        # Create a button to view A and B.
        b = gtk.Button("View A and B")
        vbox.pack_start(b)
        b.connect("event", self.button_press)
        # ----------------------------------------------------------------------
        window.add(vbox)
        window.show_all()
    # --------------------------------------------------------------------------
    def quit_event(self, widget=None, event=None):
        """Quit."""
        gtk.main_quit()
    # --------------------------------------------------------------------------
    def generate_variable_values(self, widget=None):
        """Generate values for A and B."""
        self.d_variable_value = {
            "A" : random.randint(0, 10),
            "B" : random.randint(0, 10),
            }

        print "I generated " + str(self.d_variable_value)
    # --------------------------------------------------------------------------
    def button_press(self, button, event):
        """button_press method."""
        if event.type == gtk.gdk.BUTTON_PRESS:
            menu = self.create_menu()
            menu.popup(None, None, None, event.button, event.time)
            return True

        return False
    # --------------------------------------------------------------------------
    def create_menu(self):
        """Create a menu showing A and B."""
        # How can I update the menu after the user presses the
        # "generate" button?

        # If there are no values for A and B, generate them.
        if not self.d_variable_value:
            self.generate_variable_values()

        # Show A and B in a menu.
        menu = gtk.Menu()

        print self.d_variable_value
        for key, value in sorted(self.d_variable_value.items()):

            text = key + " " + str(value)
            item = gtk.MenuItem(text)
            item.show()
            menu.append(item)

        return menu
# ------------------------------------------------------------------------------
if __name__ == "__main__":
    Generator()
    gtk.main()