Make a simple graphical interface with Tkinter

tkinter brief introduction

tkinter yes Python Bring one with you GUI package . The advantages and disadvantages are obvious ：

advantage ： Simple 、 Fast 、 No installation required

shortcoming ： Interface Retro , Lack of support for some complex functions

（ Be careful ,Python2 Of tkinter The name is Tkinter, We won't discuss it ）

start-up tkinter

Enter at the command line

python -m tkinter

It will pop up a tkinter window ：

The top version is 8.6, Click on click me! It seems that nothing will happen , Click on QUIT You can quit .

Let's introduce tkinter Simple usage , More can go to GUI What is it? (biancheng.net) or

Python GUI Programming (Tkinter) | Novice tutorial (runoob.com) or Tkinter 8.5 reference: a GUI for Python (tkdocs.com) Study .

tkinter HelloWorld

Use tkinter Create a window , The title is Hello,world.

# -*- coding:utf-8 -*-
import tkinter as tk
#  call Tk() Create main window 
root_window =tk.Tk()
#  Give the main window a name , That's the name of the window 
root_window.title('Hello,world')
# Set window size  450x300
root_window.geometry('450x300')
# Turn on the main loop , Keep the window on display 
root_window.mainloop()

1. Import ：tkinter

2. Create main window ： root_window =tk.Tk()

3. Set window properties （ title 、 size ）：

root_window.title(‘Hello,world’)

root_window.geometry(‘450x300’)

4. Turn on the main loop

    root_window.mainloop()
   

tkiner Height calculator

Now let's make a functional tkinter Program .

The end result is as follows ： We enter the height , Click calculate . Then the program calculates , Get our height and show it .

So we're up there Helloworld Start making on the basis of the program . First , Let's change the window name to “ Height calculator ”.

root_window.title(' Height calculator ')

Then we need to push the button , Put the prompt message .

# root_window.geometry('450x300') Add... Below ...
#  After setting the window , Add the component 
tk.Label(root_window, text=" Please enter height ").pack()

cms= StringVar()
tk.Entry(root_window, width=7, textvariable=cms).pack()

tk.Label(root_window, text="cm").pack()
tk.Label(root_window, text=" Your height is ").pack()

result = StringVar()
tk.Label(root_window, textvariable=result).pack()

tk.Label(root_window, text="cm").pack()

B = tk.Button(root_window, text=" Calculation ")
B.pack()

We mainly use three components ,tk.Label 、tk.Entry and tk.Button, Respectively represent text labels 、 Input box 、 Button . After creating the component, you need to call .pack() Methods place , Otherwise, it will not appear on the interface .

explain ： With this tk.Label For example . Parameter needs to be passed into its parent container ( Here is root_window), Written content (text=“ Please enter height ”). And then call .pack() Method to put it on the window .

tk.Label(root_window, text=" Please enter height ").pack()

We can also make Label The text of is a variable . Now let's create a variable result = StringVar(), And then result As tk.Label Parameters of .

result = StringVar() tk.Label(root_window, textvariable=result).pack()

But after clicking calculate , There will be no action , We also need to bind the click button to the function .

We define functions calculate To achieve the function , Get the input data first (cmt.get()), Then set the data of the output text (result.set()).

def calculate(*args):
    try:
        value = float(cms.get())
        result.set(value)
    except ValueError:
        pass

And through command=calculate take calculate Method and click button binding .

B = tk.Button(root_window, text=" Calculation ",command=calculate)

Complete code ：

# -*- coding:utf-8 -*-
import tkinter as tk
from tkinter import *

#  call Tk() Create main window 
root_window = tk.Tk()
#  Give the main window a name , That's the name of the window 
root_window.title(' Height calculator ')
#  Set window size  450x300
root_window.geometry('450x300')

# root_window.geometry('450x300') Add... Below ...
#  After setting the window , Add the component 
tk.Label(root_window, text=" Please enter height ").pack()

cms = StringVar()
tk.Entry(root_window, width=7, textvariable=cms).pack()

tk.Label(root_window, text="cm").pack()
tk.Label(root_window, text=" Your height is ").pack()

result = StringVar()
tk.Label(root_window, textvariable=result).pack()

tk.Label(root_window, text="cm").pack()


def calculate(*args):
    try:
        value = float(cms.get())
        result.set(value)
    except ValueError:
        pass


B = tk.Button(root_window, text=" Calculation ", command=calculate)
B.pack()

#  Turn on the main loop , Keep the window on display 
root_window.mainloop()

In addition to .pack() Place components , Another more flexible way is .grid(row=r,column=0) The way . In this way, the interface is used as a grid , Then place components on the grid .

#  After setting the window , Add the component 
tk.Label(root_window, text=" Please enter height ",).grid(row=0,column=0)

cms = StringVar()
tk.Entry(root_window, width=7, textvariable=cms).grid(row=0,column=1)

tk.Label(root_window, text="cm").grid(row=0,column=2)
tk.Label(root_window, text=" Your height is ").grid(row=1,column=0)

result = StringVar()
tk.Label(root_window, textvariable=result).grid(row=1,column=1)

tk.Label(root_window, text="cm").grid(row=1,column=2)


def calculate(*args):
    try:
        value = float(cms.get())
        result.set(value)
    except ValueError:
        pass


B = tk.Button(root_window, text=" Calculation ", command=calculate)
B.grid(row=3,column=3)

Of course , If you think the font is too small , It can also be in font Parameter setting ,font It's a triple ( family, size, style), Namely （ typeface , size , Format ）.

tk.Label(root_window, text=" Please enter height ",font=("Courier", 24, "italic"),height=3).grid(row=0,column=0)

tkinter BMI Calculator

Minor modifications , We can make a BMI Calculator ：

Code ：

# -*- coding:utf-8 -*-
import tkinter as tk
from tkinter import *

#  call Tk() Create main window 
root_window = tk.Tk()
#  Give the main window a name , That's the name of the window 
root_window.title('BMI Calculator ')
#  Set window size  450x300
root_window.geometry('450x300')

# root_window.geometry('450x300') Add... Below ...
#  After setting the window , Add the component 
tk.Label(root_window, text=" Please enter height cm",height=3).grid(row=0,column=0)
cms = StringVar()
tk.Entry(root_window, width=7, textvariable=cms).grid(row=0,column=1)
tk.Label(root_window, text="cm").grid(row=0,column=2)

tk.Label(root_window, text=" Please lose your weight kg",height=3).grid(row=1,column=0)
kg = StringVar()
tk.Entry(root_window, width=7, textvariable=kg).grid(row=1,column=1)
tk.Label(root_window, text="kg").grid(row=1,column=2)


tk.Label(root_window, text=" you BMI yes ").grid(row=2,column=0)
result = StringVar()
tk.Label(root_window, textvariable=result).grid(row=2,column=1)



def calculate(*args):
    try:
        cm_ = float(cms.get())
        kg_ = float(kg.get())
        value_ =  kg_ /  ((cm_/100) **2)
        value_ = value_.__round__(3)
        result.set(value_)
    except ValueError:
        pass


B = tk.Button(root_window, text=" Calculation ", command=calculate)
B.grid(row=3,column=3)

#  Turn on the main loop , Keep the window on display 
root_window.mainloop()