Question

Here is the code in question:

import wx


class MyFrame(wx.Frame):
    """
    This is MyFrame.  It just shows a few controls on a wxPanel,
    and has a simple menu.
    """

    def __init__(self, parent, title):
        wx.Frame.__init__(self, parent, -1, title,
                          pos=(150, 150), size=(350, 200))

        # Create the menubar
        menuBar = wx.MenuBar()

        # and a menu
        menu = wx.Menu()

        # add an item to the menu, using \tKeyName automatically
        # creates an accelerator, the third param is some help text
        # that will show up in the statusbar
        menu.Append(wx.ID_EXIT, "E&xit\tAlt-X", "Exit this simple sample")

        # bind the menu event to an event handler
        self.Bind(wx.EVT_MENU, self.OnTimeToClose, id=wx.ID_EXIT)

        # and put the menu on the menubar
        menuBar.Append(menu, "&File")
        self.SetMenuBar(menuBar)

        self.CreateStatusBar()

        # Now create the Panel to put the other controls on.
        panel = wx.Panel(self)

        # and a few controls
        text = wx.StaticText(panel, -1, self.istream)
        text.SetFont(wx.Font(14, wx.SWISS, wx.NORMAL, wx.BOLD))
        text.SetSize(text.GetBestSize())
        btn = wx.Button(panel, -1, "Close")
        funbtn = wx.Button(panel, -1, "Just for fun...")

        # bind the button events to handlers
        self.Bind(wx.EVT_BUTTON, self.OnTimeToClose, btn)
        self.Bind(wx.EVT_BUTTON, self.OnFunButton, funbtn)

        # Use a sizer to layout the controls, stacked vertically and with
        # a 10 pixel border around each
        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(text, 0, wx.ALL, 10)
        sizer.Add(btn, 0, wx.ALL, 10)
        sizer.Add(funbtn, 0, wx.ALL, 10)
        panel.SetSizer(sizer)
        panel.Layout()


    def OnTimeToClose(self, evt):
        """Event handler for the button click."""
        print "See ya later!"
        self.Close()


    def OnFunButton(self, evt):
        """Event handler for the button click."""

        self.istream = raw_input('Press ENTER to EXIT...\n')


class MyApp(wx.App):

    def OnInit(self):
        frame = MyFrame(None, "Simple wxPython App")
        self.SetTopWindow(frame)

        print "Print statements go to this stdout window by default."

        frame.Show(True)
        return True


app = MyApp(redirect=True)
app.MainLoop()

I’m getting the error that the MyFrame object has no attribute istream. I am not sure why this is true because even in PyScripter under the code explorer, it lists istream as an attribute of MyFrame. I have a feeling I am missing something very fundamental here. Any thoughts?

(BTW, Ignore the indentation errors, its due to the code block formatting.)

Answer 1

The __init__ method (which expects self.istream to be defined) executes before the OnFunButton method, which defines self.istream. Thus, you are seeing the message “MyFrame has no attribute istream” because the __init__ looks for self.istream, but it has not yet been defined.

You need to define self.istream before you use the variable.