# Show how to do switchable panels.

from Tkinter import *

class App:

    def __init__(self, top=None, master=None):

        if top is None:

            if master is None:

                top = Tk()

            else:

                top = Toplevel(master)

        self.top = top

        self.buttonframe = Frame(top)

        self.buttonframe.pack()

        self.panelframe = Frame(top,  borderwidth=2, relief=GROOVE)

        self.panelframe.pack(expand=1, fill=BOTH)

        self.panels = {}

        self.curpanel = None

    def addpanel(self, name, klass):

        button = Button(self.buttonframe, text=name,

                        command=lambda self=self, name=name: self.show(name))

        button.pack(side=LEFT)

        frame = Frame(self.panelframe)

        instance = klass(frame)

        self.panels[name] = (button, frame, instance)

        if self.curpanel is None:

            self.show(name)

    def show(self, name):

        (button, frame, instance) = self.panels[name]

        if self.curpanel:

            self.curpanel.pack_forget()

        self.curpanel = frame

        frame.pack(expand=1, fill="both")

class LabelPanel:

    def __init__(self, frame):

        self.label = Label(frame, text="Hello world")

        self.label.pack()

class ButtonPanel:

    def __init__(self, frame):

        self.button = Button(frame, text="Press me")

        self.button.pack()

def main():

    app = App()

    app.addpanel("label", LabelPanel)

    app.addpanel("button", ButtonPanel)

    app.top.mainloop()

if __name__ == '__main__':

    main()