4.事件处理

对事件的反应在wxPython是称为事件处理。一个事件是当“东西”发生在您的应用程序(单击按钮、文本输入、鼠标移动等)。大部分的GUI编程由响应事件。你在绑定对象到事件使用bind()方法:

class MainWindow(wx.Frame):   def __init__(self, parent, title):           wx.Frame.__init__(self,parent, title=title, size=(200,100))           ...           menuItem = filemenu.Append(wx.ID_ABOUT, "&About"," Information about this program")           self.Bind(wx.EVT_MENU, self.OnAbout, menuItem)

This means that, from now on, when the user selects the "About" menu item, the method self.OnAbout will be executed. wx.EVT_MENU is the "select menu item" event. wxWidgets understands many other events (see the full list). The self.OnAbout method has the general declaration:

这是说，从现在开始，当用户选择了"About"按钮，self.OnAbout方法被执行。wx.EVT_MENU代表“选择按钮”事件。wxWidgets明白很多事件处理。

这个方法用下边的形式表现：

def OnAbout(self, event):         ...

这里的event是wx.Event的实例。比如一个按钮单击事件-wx.EVT-BUTTON就是一个wx.Event的实例。

def OnButtonClick(self, event):       if (some_condition):           do_something()       else:           event.Skip()      def OnEvent(self, event):

 

当一个button-click事件发生时,该方法将被调用OnButtonClick。如果some_condition是真的,我们do_something()否则我们让事件处理的更普遍的事件处理程序。现在让我们看看我们的应用程序:

'''Created on 2012-6-29@author: Administrator'''import wxclass MyFrame(wx.Frame):    def __init__(self,parent,title):        wx.Frame.__init__(self,parent,title=title,size=(500,250))                self.contrl = wx.TextCtrl(self,style=wx.TE_MULTILINE)                self.CreateStatusBar()                filemenu = wx.Menu()        menuAbout=filemenu.Append(wx.ID_ABOUT,"&About","about this program")                filemenu.AppendSeparator()          menuExit=filemenu.Append(wx.ID_EXIT,"E&xit","Close program")                    menuBar = wx.MenuBar()          menuBar.Append(filemenu,"&File")                 self.Bind(wx.EVT_MENU, self.OnAbout,menuAbout)        self.Bind(wx.EVT_MENU, self.OnExit,menuExit)                         self.SetMenuBar(menuBar)                          self.Show(True)    def OnAbout(self,e):        dlg = wx.MessageDialog(self,"A small editor","about simple editor",wx.OK)        dlg.ShowModal()        dlg.Destroy()    def OnExit(self,e):        self.Close(True)app = wx.App(False)frame = MyFrame(None,"Small Editor")app.MainLoop()