1. COME ON!! 继续前进吧

1.1. 对“信号处理”了解更多

我们再来注意一下connect()：

  object.connect(name, func, func_data)

它的返回值是一具整数型变量，这个变量决定了程序之后的运行。单个的事件或是单个的widget都可以有n多的事件处理定义，它们会按你定义时的次序执行。这个变量也可以用来取消一个事件处理定义。

  object.disconnect(id)

你也可以用singal_handler_block()和singal_handler_unblock()暂时地暂停对一种事件的处理。

  object.signal_handler_block(handler_id)

  object.signal_handler_unblock(handler_id)

1.2. Hello World的火力加强版

   1 #!/usr/bin/env python
   2 
   3 # example helloworld2.py
   4 
   5 import pygtk
   6 pygtk.require('2.0')
   7 import gtk
   8 
   9 class HelloWorld2:
  10 
  11     # Our new improved callback.  The data passed to this method
  12     # is printed to stdout.
  13     def callback(self, widget, data):
  14         print "Hello again - %s was pressed" % data
  15 
  16     # another callback
  17     def delete_event(self, widget, event, data=None):
  18         gtk.main_quit()
  19         return False
  20 
  21     def __init__(self):
  22         # Create a new window
  23         self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
  24 
  25         # This is a new call, which just sets the title of our
  26         # new window to "Hello Buttons!"
  27         self.window.set_title("Hello Buttons!")
  28 
  29         # Here we just set a handler for delete_event that immediately
  30         # exits GTK.
  31         self.window.connect("delete_event", self.delete_event)
  32 
  33         # Sets the border width of the window.
  34         self.window.set_border_width(10)
  35 
  36         # We create a box to pack widgets into.  This is described in detail
  37         # in the "packing" section. The box is not really visible, it
  38         # is just used as a tool to arrange widgets.
  39         self.box1 = gtk.HBox(False, 0)
  40 
  41         # Put the box into the main window.
  42         self.window.add(self.box1)
  43 
  44         # Creates a new button with the label "Button 1".
  45         self.button1 = gtk.Button("Button 1")
  46 
  47         # Now when the button is clicked, we call the "callback" method
  48         # with a pointer to "button 1" as its argument
  49         self.button1.connect("clicked", self.callback, "button 1")
  50 
  51         # Instead of add(), we pack this button into the invisible
  52         # box, which has been packed into the window.
  53         self.box1.pack_start(self.button1, True, True, 0)
  54 
  55         # Always remember this step, this tells GTK that our preparation for
  56         # this button is complete, and it can now be displayed.
  57         self.button1.show()
  58 
  59         # Do these same steps again to create a second button
  60         self.button2 = gtk.Button("Button 2")
  61 
  62         # Call the same callback method with a different argument,
  63         # passing a pointer to "button 2" instead.
  64         self.button2.connect("clicked", self.callback, "button 2")
  65 
  66         self.box1.pack_start(self.button2, True, True, 0)
  67 
  68         # The order in which we show the buttons is not really important, but I
  69         # recommend showing the window last, so it all pops up at once.
  70         self.button2.show()
  71         self.box1.show()
  72         self.window.show()
  73 
  74 def main():
  75     gtk.main()
  76 
  77 if __name__ == "__main__":
  78     hello = HelloWorld2()
  79     main()

这个程序的运行结果如下图：

Figure 3.1. Upgraded Hello World Example

attachment:helloworld2.png

现在你应该发现想退出程序已经不是那么简单了，只能用窗口管理器或是命令行。你可以试着再在主窗口里加一个可以用于退出程序的QUIT按钮。

程序还有一个值得注意的地方是pack_start()。你可以试着改变窗口的大小。

下面我们来看一下这个版本的上一个版本的不同之处：

首先，这个版本里没有了destroy()这个callback。

13、14行定义了一个hello()，这个和上个版本相似。不同之处是它在console里输出的文本里有connect()中传入的数据。

27行为窗口设置了一个标题。

39行定义了一个水平方向的HBox，用来放置两个按钮。42行将这个HBox加到了主窗口中。

49到64行为按钮的“clicked”定义了事件处理，不同的按钮向callback传入不同的数据，这样在调用hello()的时候就会在console上输出不同的文本。

53和66将两个按钮pack进HBox中，57和70行是显示这两个按钮。

71、72行是显示HBox和主窗口。