wxPython/demo/OOR.py

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