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="MyCustomPanel" name="MyPanel">
  13     <size>200,100</size>
  14     <object class="wxStaticText" name="label1">
  15         <label>This panel is a custom 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 MyCustomPanel(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.
  30         self.Bind(wx.EVT_SIZE, self.OnSize)
  31         t = wx.StaticText(self, -1, "MyCustomPanel")
  32         f = t.GetFont()
  33         f.SetWeight(wx.BOLD)
  34         f.SetPointSize(f.GetPointSize()+2)
  35         t.SetFont(f)
  36         self.t = t
  37
  38     def OnSize(self, evt):
  39         sz = self.GetSize()
  40         w, h = self.t.GetTextExtent(self.t.GetLabel())
  41         self.t.SetPosition(((sz.width-w)/2, (sz.height-h)/2))
  42
  43
  44 # To do it the more complex way, (see below) we need to write the
  45 # class a little differently...  This could obviously be done with a
  46 # single class, but I wanted to make separate ones to make clear what
  47 # the different requirements are.
  48 class PreMyCustomPanel(wx.Panel):
  49     def __init__(self):
  50         p = wx.PrePanel()
  51         self.PostCreate(p)
  52
  53     def Create(self, parent, id, pos, size, style, name):
  54         wx.Panel.Create(self, parent, id, pos, size, style, name)
  55         self.Bind(wx.EVT_SIZE, self.OnSize)
  56         t = wx.StaticText(self, -1, "MyCustomPanel")
  57         f = t.GetFont()
  58         f.SetWeight(wx.BOLD)
  59         f.SetPointSize(f.GetPointSize()+2)
  60         t.SetFont(f)
  61         self.t = t
  62
  63     def OnSize(self, evt):
  64         sz = self.GetSize()
  65         w, h = self.t.GetTextExtent(self.t.GetLabel())
  66         self.t.SetPosition(((sz.width-w)/2, (sz.height-h)/2))
  67
  68 #----------------------------------------------------------------------
  69
  70 class MyCustomPanelXmlHandler(xrc.XmlResourceHandler):
  71     def __init__(self):
  72         xrc.XmlResourceHandler.__init__(self)
  73         # Specify the styles recognized by objects of this type
  74         self.AddStyle("wx.NO_3D", wx.NO_3D);
  75         self.AddStyle("wx.TAB_TRAVERSAL", wx.TAB_TRAVERSAL);
  76         self.AddStyle("wx.WS_EX_VALIDATE_RECURSIVELY", wx.WS_EX_VALIDATE_RECURSIVELY);
  77         self.AddStyle("wx.CLIP_CHILDREN", wx.CLIP_CHILDREN);
  78         self.AddWindowStyles();
  79
  80     # This method and the next one are required for XmlResourceHandlers
  81     def CanHandle(self, node):
  82         return self.IsOfClass(node, "MyCustomPanel")
  83
  84     def DoCreateResource(self):
  85         # NOTE: wxWindows can be created in either a single-phase or
  86         # in a two-phase way.  Single phase is what you normally do,
  87         # and two-phase creates the instnace first, and then later
  88         # creates the actual window when the Create method is called.
  89         # (In wxPython the first phase is done using the wxPre*
  90         # function, for example, wxPreFrame, wxPrePanel, etc.)
  91         #
  92         # wxXmlResource supports either method, a premade instance can
  93         # be created and populated by xrc using the appropriate
  94         # LoadOn* method (such as LoadOnPanel) or xrc can create the
  95         # instance too, using the Load* method.  However this makes
  96         # the handlers a bit more complex.  If you can be sure that a
  97         # particular class will never be loaded using a pre-existing
  98         # instance, then you can make the handle much simpler.  I'll
  99         # show both methods below.
 100
 101         if 1:
 102             # The simple method assumes that there is no existing
 103             # instance.  Be sure of that with an assert.
 104             assert self.GetInstance() is None
 105
 106             # Now create the object
 107             panel = MyCustomPanel(self.GetParentAsWindow(),
 108                                   self.GetID(),
 109                                   self.GetPosition(),
 110                                   self.GetSize(),
 111                                   self.GetStyle("style", wx.TAB_TRAVERSAL),
 112                                   self.GetName()
 113                                   )
 114         else:
 115             # When using the more complex (but more flexible) method
 116             # the instance may already have been created, check for it
 117             panel = self.GetInstance()
 118             if panel is None:
 119                 # if not, then create the instance (but not the window)
 120                 panel = PreMyCustomPanel()
 121
 122             # Now call the panel's Create method to actually create the window
 123             panel.Create(self.GetParentAsWindow(),
 124                          self.GetID(),
 125                          self.GetPosition(),
 126                          self.GetSize(),
 127                          self.GetStyle("style", wx.TAB_TRAVERSAL),
 128                          self.GetName()
 129                          )
 130
 131         # These two things should be done in either case:
 132         # Set standard window attributes
 133         self.SetupWindow(panel)
 134         # Create any child windows of this node
 135         self.CreateChildren(panel)
 136
 137         return panel
 138
 139
 140 #----------------------------------------------------------------------
 141
 142
 143 class TestPanel(wx.Panel):
 144     def __init__(self, parent, log):
 145         self.log = log
 146         wx.Panel.__init__(self, parent, -1)
 147
 148         # make the components
 149         label = wx.StaticText(self, -1, "The lower panel was built from this XML:")
 150         label.SetFont(wx.Font(12, wx.SWISS, wx.NORMAL, wx.BOLD))
 151
 152         text = wx.TextCtrl(self, -1, resourceText,
 153                           style=wx.TE_READONLY|wx.TE_MULTILINE)
 154         text.SetInsertionPoint(0)
 155
 156         line = wx.StaticLine(self, -1)
 157
 158         # Load the resource
 159         res = xrc.EmptyXmlResource()
 160         res.InsertHandler(MyCustomPanelXmlHandler())
 161         res.LoadFromString(resourceText)
 162
 163         # Now create a panel from the resource data
 164         panel = res.LoadObject(self, "MyPanel", "MyCustomPanel")
 165
 166         # and do the layout
 167         sizer = wx.BoxSizer(wx.VERTICAL)
 168         sizer.Add(label, 0, wx.EXPAND|wx.TOP|wx.LEFT, 5)
 169         sizer.Add(text, 1, wx.EXPAND|wx.ALL, 5)
 170         sizer.Add(line, 0, wx.EXPAND)
 171         sizer.Add(panel, 1, wx.EXPAND|wx.ALL, 5)
 172
 173         self.SetSizer(sizer)
 174         self.SetAutoLayout(True)
 175
 176
 177 #----------------------------------------------------------------------
 178
 179 def runTest(frame, nb, log):
 180     win = TestPanel(nb, log)
 181     return win
 182
 183 #----------------------------------------------------------------------
 184
 185
 186
 187 overview = """<html><body>
 188 <h2><center>wx.XmlResourceHandler</center></h2>
 189
 190 Deriving a class from wx.XmlResourceHandler allows you to specify your
 191 own classes in XRC resources, and your handler class will then be used
 192 to create instances of that class when the resource is loaded.
 193
 194 </body></html>
 195 """
 196
 197
 198
 199 if __name__ == '__main__':
 200     import sys,os
 201     import run
 202     run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
 203