Tkinter switching between 2 frames and at the same time trying to make another command

Question

The code for changing pages was derived from: Switch between two frames in tkinter

Hello, I've been trying to figure out how to convert this code for changing pages into something that I could use, but I had no luck with that :( . I've been trying to make these buttons not only switch page, but do 1 more simple command at the same time, I guess that somehow i should make 1 function that would do both things, instead of 2 separate functions, but I'm still quite new to python, and even more to tkinter and everytime when i try to change these buttons commands or functions i get some kind of error, it seems that i can't find a way to do it, could you help me with that? Thanks in advance.

Edit: I have deleted some some code which wasn't needed, rest is needed i think. As for my failed attempts, I will add some tries below this code.

from tkinter import *

class App(Tk):

    def __init__(self):
        Tk.__init__(self)

        container = Frame(self)
        container.pack(side="top", fill="both", expand = True)
        self.frames = {}

        for F in (StartPage, PageOne, PageTwo):
            frame = F(container, self)
            self.frames[F] = frame
            frame.grid(row=0, column=0, sticky="nsew")
        self.show_frame(StartPage)

    def show_frame(self, cont):
        frame = self.frames[cont]
        frame.tkraise()

class StartPage(Frame):

    def __init__(self, parent, controller):
        Frame.__init__(self,parent)
        label = Label(self, text="Start Page")
        label.pack(pady=10,padx=10)
        button = Button(self, text="Visit Page 1",
                            command=lambda: controller.show_frame(PageOne))
        button.pack()

class PageOne(Frame):

    def __init__(self, parent, controller):
        Frame.__init__(self, parent)
        label = Label(self, text="Page One!!!")
        label.pack(pady=10,padx=10)
        button1 = Button(self, text="Back to Home",
                            command=lambda: controller.show_frame(StartPage))
        button1.pack()


    app = App()
    app.mainloop()

I've been trying to combines these 2 functions:

def show_frame(self, cont):
    frame = self.frames[cont]
    frame.tkraise()

def calculate(self):
    e1 = self.v1.get()
    e2 = self.v2.get()
    entry1 = int(self.entry1.get())
    entry2 = int(self.entry2.get())
    k = entry1 * entry2
    print(k)

tried to make 1 function out of theses two:

def run_all(self, cont):
    frame = self.frames[cont]
    frame.tkraise()
    e1 = self.v1.get()
    e2 = self.v2.get()
    entry1 = int(self.entry1.get())
    entry2 = int(self.entry2.get())
    k = entry1 * entry2
    print(k)

Wasn't sure what to put under parameters. Also I tried changing this buttons command:

    button = Button(self, text="Visit Page 1",
                    command=lambda: controller.show_frame(PageOne))
    button.pack()

Tried to write this command with and without lambda, but nothing worked.

Answer 1

There are a few ways to do multiple things with a button. I'd review this effbot page, for example, before moving much further, or another Tkinter tutorial

    def callback():
        controller.show_frame(PageOne)
        doSomethingElse()

    button = Button(root, command=callback)

In this case, we are creating a function that calls two other functions. This is the intuitive solution. Note that functions generated with the lambda keyword are the same as any other functions - don't let that confuse you.

Here's Something You Shouldn't Do, Although it Might Work

Alternatively, it may be tempting to write

    button = Button(root, command=lambda : [foo(), bar()]

In this case the lambda function will return a list of two values, which need to be computed by calling the two functions. That list is ignored, of course, since you're not using the return value.

Reasons why this is worse:

• funcs = [foo,bar]; lambda : (f for f in funcs) May, or may not work. In python 2, the tuple will be fully evaluated, but in python3 you get a cryptic generator expression
• It's less pythonic. Creating an anonymous list is not something I've seen done for any good reason. Related, anyone who sees method #1 (including future you) will know what you're doing. Anyone who sees method #2 will think you don't know what you're doing
• In the first case, you have a handle to the actual function you're calling. In the second case, you have an anonymous list being returned by an anonymous function. There's no need for two layers of hidden-ness
• It's significantly less extensible. If you decide later that you want to do something more complicated, or have the return values depend on each other, or short circuit (etc.) you have no way to do it with the list notation. You do if you're passing a generic function