Tkinter - How to bind a key press (not button) to call a function?

Question

Suppose I have two functions which when called opens up a Frame:

Eg:

from tkinter import *
win = Tk()

class MyFrame(Frame):
    def __init__(self, master, **kwargs):
        Frame.__init__(self, master,
        bg='white' ,**kwargs)

def FuncOne():
    frameone = MyFrame(win)
    frameone.pack()

    lbl = Label(frameone, text="ABC", font='"Serif" 247' , width=win.winfo_screenwidth(), height=win.winfo_screenheight())
    lbl.pack(fill=BOTH, expand=True)


def FuncTwo():
    frametwo = MyFrame(win)
    frametwo.pack()

    lbl = Label(frametwo, text="ABC", font='"Serif" 200', width=win.winfo_screenwidth(), height=win.winfo_screenheight())
    lbl.pack()


win.mainloop()

How do I call FuncOne and FuncTwo which opens a separate frame each time by using a side arrow key and destroy the frame in FuncOne while calling FuncTwo and vice versa?

Answer 1

The following code provides 2 functions that will create a instance of your MyFrame class. In this function we will check if the list is empty with if actual_frame: returns False when its empty and create an instances of your class. On the bottom of this function wie store this instance in the list actual_frame . If you run now another time a function if actual_frame: returns True and it will destroy this instances, clear the list and build a new instance.

from tkinter import *
win = Tk()
class MyFrame(Frame):
    def __init__(self, master, **kwargs):
        Frame.__init__(self, master,
        bg='red' ,**kwargs)
actual_frame=[]
def FuncOne(event):
    if actual_frame:
        actual_frame[0].destroy()
        actual_frame.clear()
        
    frameone = MyFrame(win)
    frameone.grid(column=0,row=0)
    lbl = Label(frameone, text="ABC", font='"Serif" 24' , width=10, height=15)
    lbl.pack(side=TOP,fill=BOTH, expand=True)
    
    actual_frame.append(frameone)

def FuncTwo(event):
    if actual_frame:
        actual_frame[0].destroy()
        actual_frame.clear()
    
    frametwo = MyFrame(win)
    frametwo.grid(column=0,row=0)
    lbl = Label(frametwo, text="XYZ", font='"Serif" 20', width=10,height=15)
    lbl.pack(side=TOP, fill=BOTH, expand=True)
    
    actual_frame.append(frametwo)

win.bind('<Left>', FuncOne)
win.bind('<Right>', FuncTwo)

win.mainloop()

Update In this update I hade made another list in that we store all the functions you like to have. The keys we use here to cycle through the list with a little help oft itertools.cycle . We call in our new binded function the function that is next or once before in the function list.

from tkinter import *
from itertools import cycle

win = Tk()
class MyFrame(Frame):
    def __init__(self, master, **kwargs):
        Frame.__init__(self, master,
        bg='red' ,**kwargs)

my_funcs=[]
actual_frame=[]

def FuncOne():
    if actual_frame:
        actual_frame[0].destroy()
        actual_frame.clear()
        
    frameone = MyFrame(win)
    frameone.grid(column=0,row=0)
    lbl = Label(frameone, text="ABC", font='"Serif" 24' , width=10, height=15)
    lbl.pack(side=TOP,fill=BOTH, expand=True)
    
    actual_frame.append(frameone)

def FuncTwo():
    if actual_frame:
        actual_frame[0].destroy()
        actual_frame.clear()
    
    frametwo = MyFrame(win)
    frametwo.grid(column=0,row=0)
    lbl = Label(frametwo, text="XYZ", font='"Serif" 20', width=10,height=15)
    lbl.pack(side=TOP, fill=BOTH, expand=True)
    
    actual_frame.append(frametwo)

def FuncThree():
    if actual_frame:
        actual_frame[0].destroy()
        actual_frame.clear()
    
    framethree = MyFrame(win)
    framethree.grid(column=0,row=0)
    lbl = Label(framethree, text="DEF", font='"Serif" 20', width=10,height=15)
    lbl.pack(side=TOP, fill=BOTH, expand=True)
    
    actual_frame.append(framethree)
    
my_funcs.append(FuncOne)
my_funcs.append(FuncTwo)
my_funcs.append(FuncThree)

cycle_of_funcs = cycle(my_funcs)

def right_way(event):
    func = next(cycle_of_funcs)
    func()
def left_way(event):
    leng = len(my_funcs)
    for function in range(leng-1):
        func = next(cycle_of_funcs)
    func()
win.bind('<Left>', left_way)
win.bind('<Right>', right_way)

win.mainloop()

I just want to leave a comment here that I think it isnt the best way of doing this, but still a possible way. Just to make sure on this answer is space for a OOP solutions [click]

Answer 2

Here are the binds for the arrow keys:

win.bind('<left>', function)
win.bind('<right>', function2) 

As for getting rid of each frame, you need someway to figure out whether the other frame exists, and if it does then destroy it.

frameone = None # Initialize it as nothing
frametwo = None # Initialize it as nothing

def FuncOne():
    global frameone, frametwo # make it accessible
    ...
    if frametwo != None:
        # Get rid of frametwo
        frametwo.destroy()
        frametwo = None 
    ...
    frameone.pack()

def FuncTwo():
    global frameone, frametwo # make it accessible
    ...
    if frameone != None:
        # Get rid of frameone
        frameone.destroy()
        frameone= None 
    ...
    frametwo.pack()

Basically, what it does is that it sets frameone and frametwo to None. Then, when a certain function is called, it sets frameone/frametwo to a frame object. Then, when the other function is called, it sees that the other frame is not none, so it destroys it and makes it none.

Answer 3

I made a picker function which is an event. There is also a frame count which tells the picker which one should it start. At the start of your function I destroy the other window. Here is my code:

from tkinter import *
win = Tk()
frame = 1



class MyFrame(Frame):
    def __init__(self, master, **kwargs):
        Frame.__init__(self, master,
        bg='white' ,**kwargs)

def FuncOne():
    global frameone
    try:
        frametwo.destroy()
    except:
        pass

    frameone = MyFrame(win)
    frameone.pack()

    lbl = Label(frameone, text="ABC", font='"Serif" 247' , width=win.winfo_screenwidth(), height=win.winfo_screenheight())
    lbl.pack(fill=BOTH, expand=True)


def FuncTwo():
    global frametwo
    try:
        frameone.destroy()
    except:
        pass

    frametwo = MyFrame(win)
    frametwo.pack()

    lbl = Label(frametwo, text="ABC", font='"Serif" 200', width=win.winfo_screenwidth(), height=win.winfo_screenheight())
    lbl.pack()
def picker(event):
    global frame
    if frame == 1:
        frame = 2
        FuncOne()

    else:
        frame = 1
        FuncTwo()
win.bind('<Left>', picker)
win.bind('<Right>', picker)
win.mainloop()