Python Program Development - Chapter 11 Graphical User Page Programming

1. Graphical user interface and tkinter

In python 图形用户界面, you can GUIdevelop graphical page applications through , tkinterwhich is the default GUI of python. 内置模块It can be said that it is one 标准GUI库of the best. Compared with other GUIs, it is simple to operate and portable (can be used on most Unix platforms). Use, can also be applied to Windows and Mac systems), etc., you can import this module through import thinteror .from tkinter import *

import thinter

from tkinter import *

2. The root window of tkinter

(1) Creation of root window

Before programming the graphical user page, you must first 创建一个根窗口（主窗口）create a root window object through the constructor of the TK class in the tkinter module. Each program can only have one root window, but multiple sub-windows are allowed. To ensure that the graphical user page It is always running. You can use the mainloop() method to enter the message loop.
For example, the following python code:

import tkinter

window=tkinter.Tk() #创建一个根窗口对象window
window.mainloop()   #进入消息循环

The running results are as follows, a root window is generated:

(2) Basic methods of root window

You can set the root window through basic methods, as follows:
1. title()Used to set the name of the window;
2. resizable()Used to set the adjustability of the window, which is adjustable by default and does not need to be set;
3. geometry()Used to set the root window The size, this method receives a string in the format of width × height + x-axis offset + y-axis offset.
4. quit()Used to exit the window;
5. updata()Used to refresh the page.
For example, the following python code creates a root window object window, sets the root window name and makes it adjustable:

import tkinter

window = tkinter.Tk()  # 创建一个根窗口对象window
window.title("我的GUI页面")  # 设置根窗口的名称
window.resizable()  # 使根窗口可调，即可任意调节其长宽
window.mainloop()  # 进入消息循环

The running results are as follows:

the window can be adjusted:

3. Geometric Layout Manager

Components in tkinter can be laid out through the geometric layout manager, which is divided into three types: pack, grid and place 同一父窗口中只能使用一种几何布局管理器.

(1) Pack layout

The pack layout can be regarded as a container/package. It is called to pack()方法add the component to the parent component. It has several properties:
1. expand sets the filling method of the component;
2. fill sets whether the component fills additional space. The value can be none. , x, y or both;
3. side sets the distribution mode of components. The value can be Top, bottom, left or right. The default value is top.

(2) grid layout

The call grid()方法can be used to divide the parent component into a two-dimensional table, which has several properties:
1. row sets the row of the component;
2. column sets the column of the component;
3. rowspan sets the number of rows occupied by the component.

(3) place layout

The call place方法can place the component in a specific position. It has several attributes:
1. anchor sets the position of other options of the component;
2. relx and rely set the position relative to the window width and height, and the value range is [0,1.0 ], where relx=0.5, rely=0.5 is in the center;
3. x, y set the coordinates of the absolute layout, the unit is px.

4. tkinter component

(1) Label

Label labels are used 显示信息to display text and bitmaps. Labels are created through the constructor Label() of the Label class.
This component has the following commonly used properties:

Attributes	Function
anchor	Set the position of text and images, default is center
background	Set the background color of the label
borderwidth	Set the label border width (px), the default value is 2px
foreground	Set foreground color
height	Set the height of the label
width	Set the width of the label
image	Set image to display on label
Padx	Additional padding to the left and right of the text
Paddy	Additional padding above and below text
state	Label status
justify	Set alignment, default is center
text	Set text
relief	Set the label style, the default is flat
For example, the following python code:

import tkinter

window = tkinter.Tk()
a = tkinter.Label(window, anchor="s", height=20, width=30, text="HELLO WORLD!", background="yellow")  # 创建一个标签
a.pack()  # 通过pack()方法布局
window.mainloop()

The running results are as follows:

(2) Button

A button object can be created through the constructor Button() of the Button class. This component has the following commonly used properties:

Attributes	Function
activebackground	The background color of the button when the mouse is over
activeforeground	The foreground color of the button when the mouse is placed on it
background	The background color of the button
borderwidth	Border width, default is 2 pixels
foreground	Normal foreground (text) color
height	high
width	width
image	image to display
Padx	Additional padding to the left and right of the text
Paddy	Additional padding above and below text
text	The text content of the button
command	Action triggered when button is clicked

For example, the following python code creates a button, the button is black, and the content is displayed when the button is clicked:

import tkinter

window = tkinter.Tk()
b = tkinter.Button(window, text="HELLO WORLD!", background="black")
b.pack()
window.mainloop()

The running results are as follows:

click the button and the button displays the content:

(3) Text box

For example, the following python code:

import tkinter

widows=tkinter.Tk()
E=tkinter.Entry(widows,width=50,fg='red',background='blue')
E.pack()
widows.mainloop()

The running results are as follows:

You can enter text in the text box:

……