| 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 | EVT_BUTTON(self, BTN1, self.OnFindButton1) |
| 36 | EVT_BUTTON(self, BTN2, self.OnFindButton2) |
| 37 | |
| 38 | |
| 39 | def OnFindButton1(self, evt): |
| 40 | win = self.FindWindowById(BTN1) |
| 41 | if win is None: |
| 42 | self.log.write("***** OOPS! None returned...\n") |
| 43 | return |
| 44 | className = win.__class__.__name__ |
| 45 | if className in ["wxButton", "wxButtonPtr"]: |
| 46 | self.log.write("The types are the same! <grin>\n") |
| 47 | else: |
| 48 | self.log.write("Got %s, expected wxButton or wxButtonPtr\n" % className) |
| 49 | |
| 50 | |
| 51 | |
| 52 | def OnFindButton2(self, evt): |
| 53 | win = self.FindWindowById(BTN2) |
| 54 | if win is None: |
| 55 | self.log.write("***** OOPS! None returned...\n") |
| 56 | return |
| 57 | if win is self.btn2: |
| 58 | self.log.write("The objects are the same! <grin>\n") |
| 59 | else: |
| 60 | self.log.write("The objects are NOT the same! <frown>\n") |
| 61 | |
| 62 | |
| 63 | #---------------------------------------------------------------------- |
| 64 | |
| 65 | def runTest(frame, nb, log): |
| 66 | win = TestPanel(nb, log) |
| 67 | return win |
| 68 | |
| 69 | #---------------------------------------------------------------------- |
| 70 | |
| 71 | |
| 72 | overview = """\ |
| 73 | <html><body> |
| 74 | <h2>Original Object Return</h2> |
| 75 | |
| 76 | <p>Several methods in wxWindows return pointers to base class objects, |
| 77 | when in fact the actual object pointed to is of a derived type. Since |
| 78 | SWIG isn't able to tell the actual type it just creates a new Python |
| 79 | shadow object of the base type to wrap around the base type pointer |
| 80 | and returns it. |
| 81 | |
| 82 | <p>In wxPython this can cause annoying issues. For example if you |
| 83 | call: |
| 84 | |
| 85 | <pre> |
| 86 | |
| 87 | myText = someWindow.FindWindowById(txtID) |
| 88 | </pre> |
| 89 | |
| 90 | expecting to get a wxTextCtrl you will actually get a wxWindow object |
| 91 | instead. If you then try to call SetValue on that object you'll get |
| 92 | an exception since there is no such method. This is the reason for |
| 93 | the wxPyTypeCast hack that has been in wxPython for so long. |
| 94 | |
| 95 | <p>Even with wxPyTypeCast there is the issue that the object returned |
| 96 | is not the same one that was created in Python originally, but a new |
| 97 | object of the same type that wraps the same C++ pointer. If the |
| 98 | programmer has set additional attributes of that original object they |
| 99 | will not exist in the new object. |
| 100 | |
| 101 | <p>For a long time now I have wanted to do away with wxPyTypeCast and |
| 102 | also find a way to return the original Python object from methods like |
| 103 | FindWindowById. This project naturally divides into two phases: |
| 104 | |
| 105 | <p><ol> |
| 106 | |
| 107 | <li>Teach the wrapper methods how to return objects of the right type, |
| 108 | and be able to then turn wxPyTypeCast in to a no-op. |
| 109 | |
| 110 | <li>Be able to return the original Python shadow object if it still exists. |
| 111 | |
| 112 | </ol> |
| 113 | |
| 114 | <p>The first button below shows the first of these phases (<i>working</i>) |
| 115 | and the second will show #2 (<i>not yet working.</i>) |
| 116 | |
| 117 | </body></html> |
| 118 | """ |