How to change which tkinter Button is highlighted via arrow keys?

There you go. I have bound the arrow keys to the buttons. You can navigate using them. The base is ready, I believe but you can of course make any changes you want with the navigation.

The way it works is that I store the buttons in a 2D list, so that I can refer to them by its 2D position. I store the current highlighted button's position (default is [0,0]) in a separate variable. On pressing the keys, the current button's border is set to default and the next button is highlighted.

from tkinter import *import tkinterKeyboard_App = tkinter.Tk()buttons = [    '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '=',    'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '<-',    'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '"',    'z', 'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/', 'SHIFT',    ' Space ',]curBut = [-1,-1]buttonL = [[]]entry = Text(Keyboard_App, width=97, height=8)entry.grid(row=0, columnspan=15)varRow = 1varColumn = 0def leftKey(event):    if curBut == [-1,-1]:        curBut[:] = [0,0]        buttonL[0][0].configure(highlightbackground='red')    elif curBut[0] == 4:        buttonL[curBut[0]][curBut[1]].configure(highlightbackground='#d9d9d9')        curBut[:] = [0,10]        buttonL[0][10].configure(highlightbackground='red')    else:        buttonL[curBut[0]][curBut[1]].configure(highlightbackground='#d9d9d9')        curBut[:] = [curBut[0], (curBut[1]-1)%11]        buttonL[curBut[0]][curBut[1]%11].configure(highlightbackground='red')def rightKey(event):    if curBut == [-1,-1]:        curBut[:] = [0,0]        buttonL[0][0].configure(highlightbackground='red')    elif curBut[0] == 4:        buttonL[curBut[0]][curBut[1]].configure(highlightbackground='#d9d9d9')        curBut[:] = [0,0]        buttonL[0][0].configure(highlightbackground='red')    else:        buttonL[curBut[0]][curBut[1]].configure(highlightbackground='#d9d9d9')        curBut[:] = [curBut[0], (curBut[1]+1)%11]        buttonL[curBut[0]][curBut[1]%11].configure(highlightbackground='red')def upKey(event):    if curBut == [-1,-1]:        curBut[:] = [0,0]        buttonL[0][0].configure(highlightbackground='red')    elif curBut[0] == 0:        buttonL[curBut[0]][curBut[1]].configure(highlightbackground='#d9d9d9')        curBut[:] = [(curBut[0]-1)%5, 0]        buttonL[curBut[0]][curBut[1]%11].configure(highlightbackground='red')    else:        buttonL[curBut[0]][curBut[1]].configure(highlightbackground='#d9d9d9')        curBut[:] = [(curBut[0]-1)%5, curBut[1]]        buttonL[curBut[0]][curBut[1]%11].configure(highlightbackground='red')def downKey(event):    if curBut == [-1,-1]:        curBut[:] = [0,0]        buttonL[0][0].configure(highlightbackground='red')    elif curBut[0] == 3:        buttonL[curBut[0]][curBut[1]].configure(highlightbackground='#d9d9d9')        curBut[:] = [(curBut[0]+1)%5, 0]        buttonL[curBut[0]][curBut[1]%11].configure(highlightbackground='red')    else:        buttonL[curBut[0]][curBut[1]].configure(highlightbackground='#d9d9d9')        curBut[:] = [(curBut[0]+1)%5, curBut[1]]        buttonL[curBut[0]][curBut[1]%11].configure(highlightbackground='red')def select(value, x, y):    if curBut != [-1,-1]:        buttonL[curBut[0]][curBut[1]].configure(highlightbackground='#d9d9d9')    curBut[:] = [x,y]    buttonL[x][y].configure(highlightbackground='red')    if value == "<-":        input = entry.get("1.0", 'end-2c')        entry.delete("1.0", END)        entry.insert("1.0", input, END)    elif value == " Space ":        entry.insert(tkinter.END, ' ')    elif value == "Tab":        entry.insert(tkinter.END, '   ')    else:        entry.insert(tkinter.END, value)for button in buttons:    if button != " Space ":        but = tkinter.Button(Keyboard_App, text=button, width=5, bg="#000000", fg="#ffffff", highlightthickness=4,                        activebackground="#ffffff", activeforeground="#000000", relief="raised", padx=12,                       pady=4, bd=4, command=lambda x=button, i=varRow-1, j=varColumn: select(x, i, j))        buttonL[varRow-1].append(but)        but.grid(row=varRow, column=varColumn)    if button == " Space ":        but = tkinter.Button(Keyboard_App, text=button, width=60, bg="#000000", fg="#ffffff", highlightthickness=4,                        activebackground="#ffffff", activeforeground="#000000", relief="raised", padx=4,                       pady=4, bd=4, command=lambda x=button, i=varRow-1, j=varColumn: select(x, i, j))        buttonL[varRow-1].append(but)        but.grid(row=6, columnspan=16)    varColumn += 1    if varColumn > 10:        varColumn = 0        varRow += 1        buttonL.append([])Keyboard_App.bind('<Left>', leftKey)Keyboard_App.bind('<Right>', rightKey)Keyboard_App.bind('<Up>', upKey)Keyboard_App.bind('<Down>', downKey)Keyboard_App.mainloop()