Added wxXmlResourceHandler to wxPython and enabled it's virtuals to be

Python Callbacks.  Added a sample to the demo to show how to do it.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@16721 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

wxPython/demo/wxXmlResourceHandler.py

@@ -0,0 +1,182 @@
+
+from wxPython.wx import *
+from wxPython.xrc import *
+
+#----------------------------------------------------------------------
+
+resourceText = r'''<?xml version="1.0"?>
+<resource>
+
+<!-- Notice that the class is NOT a standard wx class -->
+
+<object class="MyBluePanel" name="MyPanel">
+    <size>200,100</size>
+    <object class="wxStaticText" name="lable1">
+        <label>This blue panel is a class derived from wxPanel,\nand is loaded by a custom wxXmlResourceHandler.</label>
+        <pos>10,10</pos>
+    </object>
+</object>
+</resource>
+'''
+
+#----------------------------------------------------------------------
+
+class MyBluePanel(wxPanel):
+    def __init__(self, parent, id, pos, size, style, name):
+        wxPanel.__init__(self, parent, id, pos, size, style, name)
+
+        # This is the little bit of customization that we do for this
+        # silly example.  It could just as easily have been done in
+        # the resource.
+        self.SetBackgroundColour("BLUE")
+
+
+# To do it the more complex way, (see below) we need to write the
+# class a little differently...  This could obviously be done with a
+# single class, but I wanted to make separate ones to make clear what
+# the different requirements are.
+class PreMyBluePanel(wxPanel):
+    def __init__(self):
+        p = wxPrePanel()
+        self.this = p.this
+
+    def Create(self, parent, id, pos, size, style, name):
+        wxPanel.Create(self, parent, id, pos, size, style, name)
+        self.SetBackgroundColour("BLUE")
+
+#----------------------------------------------------------------------
+
+class MyBluePanelXmlHandler(wxXmlResourceHandler):
+    def __init__(self):
+        wxXmlResourceHandler.__init__(self)
+        # Specify the styles recognized by objects of this type
+        self.AddStyle("wxNO_3D", wxNO_3D);
+        self.AddStyle("wxTAB_TRAVERSAL", wxTAB_TRAVERSAL);
+        self.AddStyle("wxWS_EX_VALIDATE_RECURSIVELY", wxWS_EX_VALIDATE_RECURSIVELY);
+        self.AddStyle("wxCLIP_CHILDREN", wxCLIP_CHILDREN);
+        self.AddWindowStyles();
+
+    # This method and the next one are required for XmlResourceHandlers
+    def CanHandle(self, node):
+        return self.IsOfClass(node, "MyBluePanel")
+
+    def DoCreateResource(self):
+        # NOTE: wxWindows can be created in either a single-phase or
+        # in a two-phase way.  Single phase is what you normally do,
+        # and two-phase creates the instnace first, and then later
+        # creates the actual window when the Create method is called.
+        # (In wxPython the first phase is done using the wxPre*
+        # function, for example, wxPreFrame, wxPrePanel, etc.)
+        #
+        # wxXmlResource supports either method, a premade instance can
+        # be created and populated by xrc using the appropriate
+        # LoadOn* method (such as LoadOnPanel) or xrc can create the
+        # instance too, using the Load* method.  However this makes
+        # the handlers a bit more complex.  If you can be sure that a
+        # particular class will never be loaded using a pre-existing
+        # instance, then you can make the handle much simpler.  I'll
+        # show both methods below.
+
+        if 0:
+            # The simple method assumes that there is no existing
+            # instance.  Be sure of that with an assert.
+            assert self.GetInstance() is None
+
+            # Now create the object
+            panel = MyBluePanel(self.GetParentAsWindow(),
+                                self.GetID(),
+                                self.GetPosition(),
+                                self.GetSize(),
+                                self.GetStyle("style", wxTAB_TRAVERSAL),
+                                self.GetName()
+                                )
+        else:
+            # When using the more complex (but more flexible) method
+            # the instance may already have been created, check for it
+            panel = self.GetInstance()
+            if panel is None:
+                # if not, then create the instance (but not the window)
+                panel = PreMyBluePanel()
+
+            # Now call the panel's Create method to actually create the window
+            panel.Create(self.GetParentAsWindow(),
+                         self.GetID(),
+                         self.GetPosition(),
+                         self.GetSize(),
+                         self.GetStyle("style", wxTAB_TRAVERSAL),
+                         self.GetName()
+                         )
+
+        # These two things should be done in either case:
+        # Set standard window attributes
+        self.SetupWindow(panel)
+        # Create any child windows of this node
+        self.CreateChildren(panel)
+
+        return panel
+
+
+#----------------------------------------------------------------------
+
+
+class TestPanel(wxPanel):
+    def __init__(self, parent, log):
+        self.log = log
+        wxPanel.__init__(self, parent, -1)
+
+        # make the components
+        label = wxStaticText(self, -1, "The lower panel was built from this XML:")
+        label.SetFont(wxFont(12, wxSWISS, wxNORMAL, wxBOLD))
+
+        text = wxTextCtrl(self, -1, resourceText,
+                          style=wxTE_READONLY|wxTE_MULTILINE)
+        text.SetInsertionPoint(0)
+
+        line = wxStaticLine(self, -1)
+
+        # Load the resource
+        res = wxEmptyXmlResource()
+        res.InsertHandler(MyBluePanelXmlHandler())
+        res.LoadFromString(resourceText)
+
+        # Now create a panel from the resource data
+        panel = res.LoadObject(self, "MyPanel", "MyBluePanel")
+
+        # and do the layout
+        sizer = wxBoxSizer(wxVERTICAL)
+        sizer.Add(label, 0, wxEXPAND|wxTOP|wxLEFT, 5)
+        sizer.Add(text, 1, wxEXPAND|wxALL, 5)
+        sizer.Add(line, 0, wxEXPAND)
+        sizer.Add(panel, 1, wxEXPAND|wxALL, 5)
+
+        self.SetSizer(sizer)
+        self.SetAutoLayout(true)
+
+
+#----------------------------------------------------------------------
+
+def runTest(frame, nb, log):
+    win = TestPanel(nb, log)
+    return win
+
+#----------------------------------------------------------------------
+
+
+
+overview = """<html><body>
+<h2><center>wxXmlResourceHandler</center></h2>
+
+Deriving a class from wxXmlResourceHandler allows you to specify your
+own classes in XRC resources, and your handler class will then be used
+to create instances of that class when the resource is loaded.
+
+</body></html>
+"""
+
+
+
+if __name__ == '__main__':
+    import sys,os
+    import run
+    run.main(['', os.path.basename(sys.argv[0])])
+