Tkinter

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Tkinter#

Tkinter stands for Tk interface. tkinter is the standard Python interface for creating Graphical User Interfaces (GUI). It can run on Windows, macOS, and Linux.

Note

The Geometry is the command to actually place the form on the screeen.

Lecture Code#

"""
calculator

NOTE- MOST OF THE FORM CONTROLS/WIDGETS ARE
WRITTEN AS GLOBAL

"""

import tkinter as tk
from tkinter import messagebox
import sys


def addBoxes():

    try:
        ans = 	float(inNum1.get("1.0", "end")) + \
            	float(inNum2.get("1.0", tk.END))
    except:
        ans = "Error"

    lblAns["text"] = ans


def addButtonClick(event):
    addBoxes()


def focus_next_widget(event):
    event.widget.tk_focusNext().focus()
    return("break")


def boxClear(event):
    clearBoxes()


def clearBoxes():
    
    # the clearBoxes is also used in a "non" 
    # event function
    
    inNum1.delete("1.0", "end")
    inNum2.delete("1.0", "end")
    lblAns["text"] = ""


def close_window():

    # if you don't want to show the messagebox
    # the if statement can be deleted. The destroy
    # and exit commands are still required.
    # Tab them appropriately.
    if messagebox.askokcancel("Quit", "Do you want to quit?"):
        
        # these two are always required
        theFrame.destroy()
        sys.exit(0)

# sometimes you will it root
theFrame = tk.Tk()


# add title
theFrame.title("Calculator")

# set the height and width
frameWidth = 250
frameHeight = 150

# get the screen width and height
scrnH = theFrame.winfo_screenheight()
scrnW = theFrame.winfo_screenwidth()

# calculate the center of window
xpos = int((scrnW/2) - (frameWidth/2))
ypos = int((scrnH/2) - (frameHeight/2))

# set geometry - This command places the frame on the screen with the
# hegith x width and the position xpos, ypos in the window
# theFrame.geometry('250x150+200+200')

# Note the code is building a string
# 250X150 + xpos + ypos
theFrame.geometry(str(frameWidth)+"x" + str(frameHeight)+"+" +
                  str(xpos)+"+"+str(ypos))

# frame widgets need to be global

# label 1
tk.Label(theFrame, text="Num 1", bg="#3300CC", fg="white").place(x=10, y=10)

# add an input box 1
inNum1 = tk.Text(theFrame, height=1, width=10)
inNum1.place(x=100, y=10)
inNum1.bind("<Tab>", focus_next_widget)

# label 2
tk.Label(theFrame, text="Num 2", bg="#3300CC", fg="white").place(x=10, y=40)

# add an input box 1
inNum2 = tk.Text(theFrame, height=1, width=10)
inNum2.place(x=100, y=40)
inNum2.bind("<Tab>", focus_next_widget)

bttnAdd = tk.Button(theFrame, text="Add", height=1, width=10, command=addBoxes)
bttnAdd.place(x=100, y=70)

# bind button to multiple events
bttnAdd.bind("<Return>", addButtonClick)
bttnAdd.bind("<Button-1>", addButtonClick)
bttnAdd.bind("<Tab>", focus_next_widget)

# add answer label
lblAns = tk.Label(theFrame, text="Answer")
lblAns.place(x=10, y=70)

# add clear button
bttnClr = tk.Button(theFrame, text="Clear", fg="#000080",
                    height=1, width=10, command=clearBoxes)
bttnClr.place(x=100, y=100)

# bind our bind to events
bttnClr.bind("<Return>", boxClear)
bttnClr.bind("<Button-1>", boxClear)
bttnClr.bind("<Tab>", focus_next_widget)

# use this to close the window
# note that you have to write the close_window function
theFrame.protocol("WM_DELETE_WINDOW", close_window)

# main loop
theFrame.mainloop()
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