XRCed生成的代码分析

XRCed是wxPython附带的UI设计器,生成xrc资源文件,也可以输出python代码。本文对XRCed输出的python代码进行分析。

创建一个xrc文件如下,有两个窗口,每个窗口内一个按钮,UNTITLED.xrc:

<?xml version="1.0" encoding="utf-8"?>
<resource>
 <object class="wxFrame" name="FRAME1">
 <title></title>
 <object class="wxPanel">
  <object class="wxButton" name="myTestButton">
   <label>BUTTON</label>
  </object>
 </object>
 </object>
 <object class="wxFrame" name="FRAME2">
  <title></title>
  <object class="wxPanel">
   <object class="wxButton">
    <label>BUTTON</label>
   </object>
  </object>
 </object>
</resource>

然后生成python代码,UNTITLED_xrc.py:

# This file was automatically generated by pywxrc, do not edit by hand.
# -*- coding: UTF-8 -*-

import wx
import wx.xrc as xrc

__res = None

def get_resources():
 """ This function provides access to the XML resources in this module."""
 global __res
 if __res == None:
 __init_resources()
 return __res


class xrcFRAME1(wx.Frame):
 def PreCreate(self, pre):
  """ This function is called during the class's initialization.

  Override it for custom setup before the window is created usually to
  set additional window styles using SetWindowStyle() and SetExtraStyle()."""
  pass

 def __init__(self, parent):
  # Two stage creation (see http://wiki.wxpython.org/index.cgi/TwoStageCreation)
  pre = wx.PreFrame()
  self.PreCreate(pre)
  get_resources().LoadOnFrame(pre, parent, "FRAME1")
  self.PostCreate(pre)

  # create attributes for the named items in this container
  self.myTestButton = xrc.XRCCTRL(self, "myTestButton")


class xrcFRAME2(wx.Frame):
 def PreCreate(self, pre):
  """ This function is called during the class's initialization.

  Override it for custom setup before the window is created usually to
  set additional window styles using SetWindowStyle() and SetExtraStyle()."""
  pass

 def __init__(self, parent):
  # Two stage creation (see http://wiki.wxpython.org/index.cgi/TwoStageCreation)
  pre = wx.PreFrame()
  self.PreCreate(pre)
  get_resources().LoadOnFrame(pre, parent, "FRAME2")
  self.PostCreate(pre)

  # create attributes for the named items in this container



# ------------------------ Resource data ----------------------

def __init_resources():
 global __res
 __res = xrc.EmptyXmlResource()

 __res.Load('UNTITLED.xrc')



从生成的Python代码可以看到:

* 只生成了Frame类,而不是一个可运行的Python程序。

 为了运行显示上述的两个窗口,必须手工写如下代码:

import wx

import UNTITLED_xrc

app = wx.PySimpleApp()
frm1 = UNTITLED_xrc.xrcFRAME1(parent=None)
frm2 = UNTITLED_xrc.xrcFRAME2(parent=None)
frm1.Show()
frm2.Show()
app.MainLoop()

* 两个窗口资源在同一个文件中。

 如果要分开多个文件,只能分多个xrc文件创建。

* 该自动生成文件不应该手工编辑,见头部:“do not edit by hand”。

 所以对窗口类的自定义行为,如消息绑定,都需要继承该xrcFRAME。

 其中有个“PreCreate()”,可以在子类中覆盖,对窗口进行预创建。

* 资源仅在使用到时才装载。所以分多个xrc资源是有利的。

* 对于命名控件,如“myTestButton”会自动创建,变量名相同。