python - Switching between frames in tkinter menu

Question

I've used Tkinter to create a GUI with different menu options (a similar example is produced below). Each menu has different commands, which when clicked create a new frame. Now what is happening is if I switch to a different command, the new frame stacks below the current frame instead of replacing the old one.

I want to know what is the best way to move forward.

import Tkinter as tkinter
root = tkinter.Tk()
root.minsize(400,300)
welcome = tkinter.Frame(root).grid()
label = tkinter.Label(welcome, text="Welcome to my program").grid(row=0, column=3)
button = tkinter.Button(welcome,text="Exit",command=root.destroy).grid(row=3, column=1)
def newFrame():
newFrame = tkinter.Frame(root).grid()
newFrame_name = tkinter.Label(newFrame, text="This is another frame").grid()
menu = tkinter.Menu(root)
root.config(menu=menu)
main_menu = tkinter.Menu(menu)
menu.add_cascade(label="Main Menu", menu= main_menu)
main_menu.add_command(label="New Frame", command=newFrame)
main_menu.add_command(label="Another Frame", command=newFrame)
#menu.add_command(label="Exit", command=root.destroy, menu= filemenu)
root.mainloop()

Now if I switch between New Frame and Another Frame, the windows stack up, but I want one window to replace the other.

Any ideas? Thanks.

Answer 1

Here is a minimal example of one method I used recently; the key is in PythonGUI.show_frame, which moves the appropriate frame to the front for display.

import Tkinter as tk

class BaseFrame(tk.Frame):
    """An abstract base class for the frames that sit inside PythonGUI.

    Args:
      master (tk.Frame): The parent widget.
      controller (PythonGUI): The controlling Tk object.

    Attributes:
      controller (PythonGUI): The controlling Tk object.

    """

    def __init__(self, master, controller):
        tk.Frame.__init__(self, master)
        self.controller = controller
        self.grid()
        self.create_widgets()

    def create_widgets(self):
        """Create the widgets for the frame."""
        raise NotImplementedError


class ExecuteFrame(BaseFrame):
    """The application home page.

    Attributes:
      new_button (tk.Button): The button to switch to HomeFrame.

    """

    def create_widgets(self):
        """Create the base widgets for the frame."""
        self.new_button = tk.Button(self,
                                    anchor=tk.W,
                                    command=lambda: self.controller.show_frame(HomeFrame),
                                    padx=5,
                                    pady=5,
                                    text="Home")
        self.new_button.grid(padx=5, pady=5, sticky=tk.W+tk.E)


class HomeFrame(BaseFrame):
    """The application home page.

    Attributes:
      new_button (tk.Button): The button to switch to ExecuteFrame.

    """

    def create_widgets(self):
        """Create the base widgets for the frame."""
        self.new_button = tk.Button(self,
                                    anchor=tk.W,
                                    command=lambda: self.controller.show_frame(ExecuteFrame),
                                    padx=5,
                                    pady=5,
                                    text="Execute")
        self.new_button.grid(padx=5, pady=5, sticky=tk.W+tk.E)


class PythonGUI(tk.Tk):
    """The main window of the GUI.

    Attributes:
      container (tk.Frame): The frame container for the sub-frames.
      frames (dict of tk.Frame): The available sub-frames.

    """

    def __init__(self):
        tk.Tk.__init__(self)
        self.title("Python GUI")
        self.create_widgets()
        self.resizable(0, 0)

    def create_widgets(self):
        """Create the widgets for the frame."""             
        #   Frame Container
        self.container = tk.Frame(self)
        self.container.grid(row=0, column=0, sticky=tk.W+tk.E)

        #   Frames
        self.frames = {}
        for f in (HomeFrame, ExecuteFrame): # defined subclasses of BaseFrame
            frame = f(self.container, self)
            frame.grid(row=2, column=2, sticky=tk.NW+tk.SE)
            self.frames[f] = frame
        self.show_frame(HomeFrame)

    def show_frame(self, cls):
        """Show the specified frame.

        Args:
          cls (tk.Frame): The class of the frame to show. 

        """
        self.frames[cls].tkraise()

if __name__ == "__main__":
    app = PythonGUI()
    app.mainloop()
    exit()