wxPython/demo/XmlResourceHandler.py

   1
   2 import  wx
   3 import  wx.xrc  as  xrc
   4
   5 #----------------------------------------------------------------------
   6
   7 resourceText = r'''<?xml version="1.0"?>
   8 <resource>
   9
  10 <!-- Notice that the class is NOT a standard wx class -->
  11
  12 <object class="MyBluePanel" name="MyPanel">
  13     <size>200,100</size>
  14     <object class="wxStaticText" name="label1">
  15         <label>This blue panel is a class derived from wx.Panel,\nand is loaded by a custom XmlResourceHandler.</label>
  16         <pos>10,10</pos>
  17     </object>
  18 </object>
  19 </resource>
  20 '''
  21
  22 #----------------------------------------------------------------------
  23
  24 class MyBluePanel(wx.Panel):
  25     def __init__(self, parent, id, pos, size, style, name):
  26         wx.Panel.__init__(self, parent, id, pos, size, style, name)
  27
  28         # This is the little bit of customization that we do for this
  29         # silly example.  It could just as easily have been done in
  30         # the resource.
  31         self.SetBackgroundColour("BLUE")
  32         self.SetForegroundColour("WHITE")
  33
  34
  35 # To do it the more complex way, (see below) we need to write the
  36 # class a little differently...  This could obviously be done with a
  37 # single class, but I wanted to make separate ones to make clear what
  38 # the different requirements are.
  39 class PreMyBluePanel(wx.Panel):
  40     def __init__(self):
  41         p = wx.PrePanel()
  42         self.PostCreate(p)
  43
  44     def Create(self, parent, id, pos, size, style, name):
  45         wx.Panel.Create(self, parent, id, pos, size, style, name)
  46         self.SetBackgroundColour("BLUE")
  47         self.SetForegroundColour("WHITE")
  48
  49
  50 #----------------------------------------------------------------------
  51
  52 class MyBluePanelXmlHandler(xrc.XmlResourceHandler):
  53     def __init__(self):
  54         xrc.XmlResourceHandler.__init__(self)
  55         # Specify the styles recognized by objects of this type
  56         self.AddStyle("wx.NO_3D", wx.NO_3D);
  57         self.AddStyle("wx.TAB_TRAVERSAL", wx.TAB_TRAVERSAL);
  58         self.AddStyle("wx.WS_EX_VALIDATE_RECURSIVELY", wx.WS_EX_VALIDATE_RECURSIVELY);
  59         self.AddStyle("wx.CLIP_CHILDREN", wx.CLIP_CHILDREN);
  60         self.AddWindowStyles();
  61
  62     # This method and the next one are required for XmlResourceHandlers
  63     def CanHandle(self, node):
  64         return self.IsOfClass(node, "MyBluePanel")
  65
  66     def DoCreateResource(self):
  67         # NOTE: wxWindows can be created in either a single-phase or
  68         # in a two-phase way.  Single phase is what you normally do,
  69         # and two-phase creates the instnace first, and then later
  70         # creates the actual window when the Create method is called.
  71         # (In wxPython the first phase is done using the wxPre*
  72         # function, for example, wxPreFrame, wxPrePanel, etc.)
  73         #
  74         # wxXmlResource supports either method, a premade instance can
  75         # be created and populated by xrc using the appropriate
  76         # LoadOn* method (such as LoadOnPanel) or xrc can create the
  77         # instance too, using the Load* method.  However this makes
  78         # the handlers a bit more complex.  If you can be sure that a
  79         # particular class will never be loaded using a pre-existing
  80         # instance, then you can make the handle much simpler.  I'll
  81         # show both methods below.
  82
  83         if 1:
  84             # The simple method assumes that there is no existing
  85             # instance.  Be sure of that with an assert.
  86             assert self.GetInstance() is None
  87
  88             # Now create the object
  89             panel = MyBluePanel(self.GetParentAsWindow(),
  90                                 self.GetID(),
  91                                 self.GetPosition(),
  92                                 self.GetSize(),
  93                                 self.GetStyle("style", wx.TAB_TRAVERSAL),
  94                                 self.GetName()
  95                                 )
  96         else:
  97             # When using the more complex (but more flexible) method
  98             # the instance may already have been created, check for it
  99             panel = self.GetInstance()
 100             if panel is None:
 101                 # if not, then create the instance (but not the window)
 102                 panel = PreMyBluePanel()
 103
 104             # Now call the panel's Create method to actually create the window
 105             panel.Create(self.GetParentAsWindow(),
 106                          self.GetID(),
 107                          self.GetPosition(),
 108                          self.GetSize(),
 109                          self.GetStyle("style", wx.TAB_TRAVERSAL),
 110                          self.GetName()
 111                          )
 112
 113         # These two things should be done in either case:
 114         # Set standard window attributes
 115         self.SetupWindow(panel)
 116         # Create any child windows of this node
 117         self.CreateChildren(panel)
 118
 119         return panel
 120
 121
 122 #----------------------------------------------------------------------
 123
 124
 125 class TestPanel(wx.Panel):
 126     def __init__(self, parent, log):
 127         self.log = log
 128         wx.Panel.__init__(self, parent, -1)
 129
 130         # make the components
 131         label = wx.StaticText(self, -1, "The lower panel was built from this XML:")
 132         label.SetFont(wx.Font(12, wx.SWISS, wx.NORMAL, wx.BOLD))
 133
 134         text = wx.TextCtrl(self, -1, resourceText,
 135                           style=wx.TE_READONLY|wx.TE_MULTILINE)
 136         text.SetInsertionPoint(0)
 137
 138         line = wx.StaticLine(self, -1)
 139
 140         # Load the resource
 141         res = xrc.EmptyXmlResource()
 142         res.InsertHandler(MyBluePanelXmlHandler())
 143         res.LoadFromString(resourceText)
 144
 145         # Now create a panel from the resource data
 146         panel = res.LoadObject(self, "MyPanel", "MyBluePanel")
 147
 148         # and do the layout
 149         sizer = wx.BoxSizer(wx.VERTICAL)
 150         sizer.Add(label, 0, wx.EXPAND|wx.TOP|wx.LEFT, 5)
 151         sizer.Add(text, 1, wx.EXPAND|wx.ALL, 5)
 152         sizer.Add(line, 0, wx.EXPAND)
 153         sizer.Add(panel, 1, wx.EXPAND|wx.ALL, 5)
 154
 155         self.SetSizer(sizer)
 156         self.SetAutoLayout(True)
 157
 158
 159 #----------------------------------------------------------------------
 160
 161 def runTest(frame, nb, log):
 162     win = TestPanel(nb, log)
 163     return win
 164
 165 #----------------------------------------------------------------------
 166
 167
 168
 169 overview = """<html><body>
 170 <h2><center>wx.XmlResourceHandler</center></h2>
 171
 172 Deriving a class from wx.XmlResourceHandler allows you to specify your
 173 own classes in XRC resources, and your handler class will then be used
 174 to create instances of that class when the resource is loaded.
 175
 176 </body></html>
 177 """
 178
 179
 180
 181 if __name__ == '__main__':
 182     import sys,os
 183     import run
 184     run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
 185