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

Question

I am working on a keyboard app using tkinter library in python. I have made a keyboard. What I want is to highlight a key and on clicking on arrow keys I want to change that

Answer 1

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 tkinter

Keyboard_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 = 1
varColumn = 0

def 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('', leftKey)
Keyboard_App.bind('', rightKey)
Keyboard_App.bind('', upKey)
Keyboard_App.bind('', downKey)
Keyboard_App.mainloop()