wxPython/demo/OOR.py

   1
   2 import  wx
   3 import  wx.html as wxhtml
   4
   5 #----------------------------------------------------------------------
   6
   7 BTN1 = wx.NewId()
   8 BTN2 = wx.NewId()
   9
  10 class TestPanel(wx.Panel):
  11     def __init__(self, parent, log):
  12         wx.Panel.__init__(self, parent, -1)
  13         self.log = log
  14
  15         sizer = wx.BoxSizer(wx.VERTICAL)
  16         html = wxhtml.HtmlWindow(self, -1)
  17         html.SetPage(overview)
  18         sizer.Add(html, 1, wx.EXPAND|wx.ALL, 5)
  19
  20         btns = wx.BoxSizer(wx.HORIZONTAL)
  21         btns.Add((50, -1), 1, wx.EXPAND)
  22         btn1 = wx.Button(self, BTN1, "Find My Alter-ego") # don't save a ref to this one
  23         btns.Add(btn1)
  24         btns.Add((50, -1), 1, wx.EXPAND)
  25         self.btn2 = wx.Button(self, BTN2, "Find Myself")
  26         btns.Add(self.btn2)
  27         btns.Add((50, -1), 1, wx.EXPAND)
  28
  29         sizer.Add(btns, 0, wx.EXPAND|wx.ALL, 15)
  30
  31         self.SetSizer(sizer)
  32         self.SetAutoLayout(True)
  33
  34         self.sizer = sizer  # save it for testing later
  35
  36         self.Bind(wx.EVT_BUTTON, self.OnFindButton1, id=BTN1)
  37         self.Bind(wx.EVT_BUTTON, self.OnFindButton2, id=BTN2)
  38
  39
  40     def OnFindButton1(self, evt):
  41         win = self.FindWindowById(BTN1)
  42
  43         if win is None:
  44             self.log.write("***** OOPS! None returned...\n")
  45             return
  46
  47         className = win.__class__.__name__
  48
  49         if className in ["Button", "ButtonPtr"]:
  50             self.log.write("The types are the same! <grin>\n")
  51         else:
  52             self.log.write("Got %s, expected wxButton or wxButtonPtr\n" % className)
  53
  54
  55
  56     def OnFindButton2(self, evt):
  57         win = self.FindWindowById(BTN2)
  58
  59         if win is None:
  60             self.log.write("***** OOPS! None returned...\n")
  61             return
  62
  63         if win is self.btn2:
  64             self.log.write("The objects are the same! <grin>\n")
  65         else:
  66             self.log.write("The objects are NOT the same! <frown>\n")
  67
  68         win = evt.GetEventObject()
  69
  70         if win is None:
  71             self.log.write("***** OOPS! None returned...\n")
  72             return
  73
  74         if win is self.btn2:
  75             self.log.write("The objects are the same! <grin>\n")
  76         else:
  77             self.log.write("The objects are NOT the same! <frown>\n")
  78
  79         sizer = self.GetSizer()
  80
  81         if sizer is None:
  82             self.log.write("***** OOPS! None returned...\n")
  83             return
  84
  85         if sizer is self.sizer:
  86             self.log.write("The objects are the same! <grin>\n")
  87         else:
  88             self.log.write("The objects are NOT the same! <frown>\n")
  89
  90
  91 #----------------------------------------------------------------------
  92
  93 def runTest(frame, nb, log):
  94     win = TestPanel(nb, log)
  95     return win
  96
  97 #----------------------------------------------------------------------
  98
  99
 100 overview = """\
 101 <html><body>
 102 <h2>Original Object Return</h2>
 103
 104 <p>Several methods in wxWindows return pointers to base class objects,
 105 when in fact the actual object pointed to is of a derived type.  Since
 106 SWIG isn't able to tell the actual type it just creates a new Python
 107 shadow object of the base type to wrap around the base type pointer
 108 and returns it.
 109
 110 <p>In wxPython prior to 2.3.0 this could cause annoying issues.  For
 111 example if you called:
 112
 113 <pre>
 114
 115         myText = someWindow.FindWindowById(txtID)
 116 </pre>
 117
 118 expecting to get a wxTextCtrl you would actually get a wxWindow object
 119 instead.  If you then try to call SetValue on that object you'll get
 120 an exception since there is no such method.  This is the reason for
 121 the wxPyTypeCast hack that has been in wxPython for so long.
 122
 123 <p>Even with wxPyTypeCast there was the issue that the object returned
 124 was not the same one that was created in Python originally, but a new
 125 object of the same type that wraps the same C++ pointer.  If the
 126 programmer has set additional attributes of that original object they
 127 will not exist in the new object.
 128
 129 <p>For a long time now I have wanted to do away with wxPyTypeCast and
 130 also find a way to return the original Python object from methods like
 131 FindWindowById.  This project naturally divides into two phases:
 132
 133 <p><ol>
 134
 135 <li>Teach the wrapper methods how to return objects of the right type,
 136 and be able to then turn wxPyTypeCast in to a no-op.
 137
 138 <li>Be able to return the original Python shadow object if it still exists.
 139
 140 </ol>
 141
 142 <p>The first button below shows the first of these phases (<i>working</i>)
 143 and the second will show #2 (<i>working as of Python 2.3.2</i>)
 144
 145 </body></html>
 146 """
 147
 148
 149
 150
 151 if __name__ == '__main__':
 152     import sys,os
 153     import run
 154     run.main(['', os.path.basename(sys.argv[0])])
 155