1. 小试牛刀

下面就是packbox.py的代码，试着运行一下试试。

   1 #!/usr/bin/env python
   2 
   3 # example packbox.py
   4 
   5 import pygtk
   6 pygtk.require('2.0')
   7 import gtk
   8 import sys, string
   9 
  10 # Helper function that makes a new hbox filled with button-labels. Arguments
  11 # for the variables we're interested are passed in to this function.  We do
  12 # not show the box, but do show everything inside.
  13 
  14 def make_box(homogeneous, spacing, expand, fill, padding):
  15 
  16     # Create a new hbox with the appropriate homogeneous
  17     # and spacing settings
  18     box = gtk.HBox(homogeneous, spacing)
  19 
  20     # Create a series of buttons with the appropriate settings
  21     button = gtk.Button("box.pack")
  22     box.pack_start(button, expand, fill, padding)
  23     button.show()
  24 
  25     button = gtk.Button("(button,")
  26     box.pack_start(button, expand, fill, padding)
  27     button.show()
  28 
  29     # Create a button with the label depending on the value of
  30     # expand.
  31     if expand == True:
  32         button = gtk.Button("True,")
  33     else:
  34         button = gtk.Button("False,")
  35 
  36     box.pack_start(button, expand, fill, padding)
  37     button.show()
  38 
  39     # This is the same as the button creation for "expand"
  40     # above, but uses the shorthand form.
  41     button = gtk.Button(("False,", "True,")[fill==True])
  42     box.pack_start(button, expand, fill, padding)
  43     button.show()
  44 
  45     padstr = "%d)" % padding
  46 
  47     button = gtk.Button(padstr)
  48     box.pack_start(button, expand, fill, padding)
  49     button.show()
  50     return box
  51 
  52 class PackBox1:
  53     def delete_event(self, widget, event, data=None):
  54         gtk.main_quit()
  55         return False
  56 
  57     def __init__(self, which):
  58 
  59         # Create our window
  60         self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
  61 
  62         # You should always remember to connect the delete_event signal
  63         # to the main window. This is very important for proper intuitive
  64         # behavior
  65         self.window.connect("delete_event", self.delete_event)
  66         self.window.set_border_width(10)
  67 
  68         # We create a vertical box (vbox) to pack the horizontal boxes into.
  69         # This allows us to stack the horizontal boxes filled with buttons one
  70         # on top of the other in this vbox.
  71         box1 = gtk.VBox(False, 0)
  72 
  73         # which example to show. These correspond to the pictures above.
  74         if which == 1:
  75             # create a new label.
  76             label = gtk.Label("HBox(False, 0)")
  77 
  78             # Align the label to the left side.  We'll discuss this method
  79             # and others in the section on Widget Attributes.
  80             label.set_alignment(0, 0)
  81 
  82             # Pack the label into the vertical box (vbox box1).  Remember that 
  83             # widgets added to a vbox will be packed one on top of the other in
  84             # order.
  85             box1.pack_start(label, False, False, 0)
  86 
  87             # Show the label
  88             label.show()
  89 
  90             # Call our make box function - homogeneous = False, spacing = 0,
  91             # expand = False, fill = False, padding = 0
  92             box2 = make_box(False, 0, False, False, 0)
  93             box1.pack_start(box2, False, False, 0)
  94             box2.show()
  95 
  96             # Call our make box function - homogeneous = False, spacing = 0,
  97             # expand = True, fill = False, padding = 0
  98             box2 = make_box(False, 0, True, False, 0)
  99             box1.pack_start(box2, False, False, 0)
 100             box2.show()
 101 
 102             # Args are: homogeneous, spacing, expand, fill, padding
 103             box2 = make_box(False, 0, True, True, 0)
 104             box1.pack_start(box2, False, False, 0)
 105             box2.show()
 106 
 107             # Creates a separator, we'll learn more about these later, 
 108             # but they are quite simple.
 109             separator = gtk.HSeparator()
 110 
 111             # Pack the separator into the vbox. Remember each of these
 112             # widgets is being packed into a vbox, so they'll be stacked
 113             # vertically.
 114             box1.pack_start(separator, False, True, 5)
 115             separator.show()
 116 
 117             # Create another new label, and show it.
 118             label = gtk.Label("HBox(True, 0)")
 119             label.set_alignment(0, 0)
 120             box1.pack_start(label, False, False, 0)
 121             label.show()
 122 
 123             # Args are: homogeneous, spacing, expand, fill, padding
 124             box2 = make_box(True, 0, True, False, 0)
 125             box1.pack_start(box2, False, False, 0)
 126             box2.show()
 127 
 128             # Args are: homogeneous, spacing, expand, fill, padding
 129             box2 = make_box(True, 0, True, True, 0)
 130             box1.pack_start(box2, False, False, 0)
 131             box2.show()
 132 
 133             # Another new separator.
 134             separator = gtk.HSeparator()
 135             # The last 3 arguments to pack_start are:
 136             # expand, fill, padding.
 137             box1.pack_start(separator, False, True, 5)
 138             separator.show()
 139         elif which == 2:
 140             # Create a new label, remember box1 is a vbox as created 
 141             # near the beginning of __init__()
 142             label = gtk.Label("HBox(False, 10)")
 143             label.set_alignment( 0, 0)
 144             box1.pack_start(label, False, False, 0)
 145             label.show()
 146 
 147             # Args are: homogeneous, spacing, expand, fill, padding
 148             box2 = make_box(False, 10, True, False, 0)
 149             box1.pack_start(box2, False, False, 0)
 150             box2.show()
 151 
 152             # Args are: homogeneous, spacing, expand, fill, padding
 153             box2 = make_box(False, 10, True, True, 0)
 154             box1.pack_start(box2, False, False, 0)
 155             box2.show()
 156 
 157             separator = gtk.HSeparator()
 158             # The last 3 arguments to pack_start are:
 159             # expand, fill, padding.
 160             box1.pack_start(separator, False, True, 5)
 161             separator.show()
 162 
 163             label = gtk.Label("HBox(False, 0)")
 164             label.set_alignment(0, 0)
 165             box1.pack_start(label, False, False, 0)
 166             label.show()
 167 
 168             # Args are: homogeneous, spacing, expand, fill, padding
 169             box2 = make_box(False, 0, True, False, 10)
 170             box1.pack_start(box2, False, False, 0)
 171             box2.show()
 172 
 173             # Args are: homogeneous, spacing, expand, fill, padding
 174             box2 = make_box(False, 0, True, True, 10)
 175             box1.pack_start(box2, False, False, 0)
 176             box2.show()
 177 
 178             separator = gtk.HSeparator()
 179             # The last 3 arguments to pack_start are:
 180             # expand, fill, padding.
 181             box1.pack_start(separator, False, True, 5)
 182             separator.show()
 183 
 184         elif which == 3:
 185 
 186             # This demonstrates the ability to use pack_end() to
 187             # right justify widgets. First, we create a new box as before.
 188             box2 = make_box(False, 0, False, False, 0)
 189 
 190             # Create the label that will be put at the end.
 191             label = gtk.Label("end")
 192             # Pack it using pack_end(), so it is put on the right
 193             # side of the hbox created in the make_box() call.
 194             box2.pack_end(label, False, False, 0)
 195             # Show the label.
 196             label.show()
 197 
 198             # Pack box2 into box1
 199             box1.pack_start(box2, False, False, 0)
 200             box2.show()
 201 
 202             # A separator for the bottom.
 203             separator = gtk.HSeparator()
 204 
 205             # This explicitly sets the separator to 400 pixels wide by 5
 206             # pixels high. This is so the hbox we created will also be 400
 207             # pixels wide, and the "end" label will be separated from the
 208             # other labels in the hbox. Otherwise, all the widgets in the
 209             # hbox would be packed as close together as possible.
 210             separator.set_size_request(400, 5)
 211             # pack the separator into the vbox (box1) created near the start 
 212             # of __init__()
 213             box1.pack_start(separator, False, True, 5)
 214             separator.show()
 215 
 216         # Create another new hbox.. remember we can use as many as we need!
 217         quitbox = gtk.HBox(False, 0)
 218 
 219         # Our quit button.
 220         button = gtk.Button("Quit")
 221 
 222         # Setup the signal to terminate the program when the button is clicked
 223         button.connect("clicked", lambda w: gtk.main_quit())
 224         # Pack the button into the quitbox.
 225         # The last 3 arguments to pack_start are:
 226         # expand, fill, padding.
 227         quitbox.pack_start(button, True, False, 0)
 228         # pack the quitbox into the vbox (box1)
 229         box1.pack_start(quitbox, False, False, 0)
 230 
 231         # Pack the vbox (box1) which now contains all our widgets, into the
 232         # main window.
 233         self.window.add(box1)
 234 
 235         # And show everything left
 236         button.show()
 237         quitbox.show()
 238 
 239         box1.show()
 240         # Showing the window last so everything pops up at once.
 241         self.window.show()
 242 
 243 def main():
 244     # And of course, our main loop.
 245     gtk.main()
 246     # Control returns here when main_quit() is called
 247     return 0
 248 
 249 if __name__ =="__main__":
 250 ##    if len(sys.argv) != 2:
 251 ##        sys.stderr.write("usage: packbox.py num, where num is 1, 2, or 3.\n")
 252 ##        sys.exit(1)
 253 ##    PackBox1(string.atoi(sys.argv[1]))
 254     PackBox1(string.atoi('3'))
 255 
 256     main()

程序的14到50行定义了一个make_box()，是用来创建一个有gtk.Button在里面的box。它返回一个box的指针。

52到241行定义了类packbox1的初始化init()，它用来创建一个主窗口，然后根据不同的命令行传入参数，在主窗口的gtk.VBox中建立三个gtk.HBox。 If a 1 is passed, lines 75-138 create a window displaying the five unique packing arrangements that are available when varying the homogeneous, expand and fill parameters. If a 2 is passed, lines 140-182 create a window displaying the various combinations of fill with spacing and padding. Finally, if a 3 is passed, lines 188-214 create a window displaying the use of the pack_start() method to left justify the buttons and pack_end() method to right justify a label. Lines 215-235 create a horizontal box containing a button that is packed into the vertical box. The button "clicked" signal is connected to the PyGTK main_quit() function to terminate the program.

Lines 250-252 check the command line arguments and exit the program using the sys.exit() function if there isn't exactly one argument. Line 253 creates a PackBox1 instance. Line 254 invokes the main() function to start the GTK event processing loop.

In this example program, the references to the various widgets (except the window) are not saved in the object instance attributes because they are not needed later.