目录

1.简介

功能按钮也称为按钮，在窗口组件中可以设计在单击功能按钮时，执行某一个特定的动作，这个动作也称为callback方法，也就是说我们可以将功能按钮当作用户与程序沟通的桥梁。功能按钮上面可以有文字，或是和标签一样可以有图像，如果是文字样式的功能按钮，可以设定此文字的字形。它的语法格式如下：

Button(父对象, options, ……)

Button()方法的第一个参数是父对象，表示这个功能按钮将建立在哪一个窗口内。下列是Button()方法内其他常用的options参数。

当单机功能按钮时可以显示字符串”Hello world”，底色是浅黄色，字符串颜色是黑色

from tkinter import *

def msgShow():
	label["text"] = "Hello world"
	label["bg"] = "lightyellow"
	label["fg"] = "black"

root = Tk()
label = Label(root)     # 创建label标签
btn = Button(root, text = "打印消息", command = msgShow)

label.pack()
btn.pack()
root.mainloop()

上述程序是先建立一个不含属性的标签对象label，然后建立一个功能按钮。单机按钮时，会启动msgShow函数，然后此函数会执行标签label的内容。也可以用config()方法一次性设置所有的label属性:

label.config(text = "Hello world", bg = "lightyellow", fg = "black")

 下面新增按钮功能

btn1 = Button(root, text = "结束", width = 20, command = root.destroy)

root.destroy可以关闭root窗口对象，同时结束程序。另一个常用方法是quit，可以让Python Shell内执行的程序结束，但是root窗口则继续执行。

1.1定时程序设计

from tkinter import *

counter = 0                                  # 计数的初始值
def run_counter(digit):                      # 数字变量内容的变动
	def counting():                          # 变动数字方法
		global counter                       # 定义这是全局变量
		counter += 1
		digit.config(text = str(counter))    # 显示数字内容
		digit.after(1000, counting)          # 隔一次后调用counting
	counting()                                 # 持续调用 

root = Tk()
digit = Label(root, bg = "lightyellow", fg = "black",
	height = 3, width = 10,
	font = "黑体 20 bold")

digit.pack()
run_counter(digit)
btn = Button(root, text ="结束", width = 15, command = root.destroy)

btn.pack()
root.mainloop()

1.2颜色选择程序设计

from tkinter import *

def yellow():                                  # 自定义颜色背景
	root.config(bg = "yellow")
def blue():
	root.config(bg = "blue")
def red():
	root.config(bg = "red")

root = Tk()
root.geometry("500x500")
yellowbtn = Button(root, text = "yellow", command = yellow)
bluebtn = Button(root, text = "blue", command = blue)
redbtn = Button(root, text = "red", command = red)
exitbtn = Button(root, text = "Exit", command = root.destroy)

yellowbtn.pack(anchor = S, side = RIGHT, padx = 10, pady = 10)
bluebtn.pack(anchor = S, side = RIGHT, padx = 10, pady = 10)
redbtn.pack(anchor = S, side = RIGHT, padx = 10, pady = 10)
exitbtn.pack(anchor = S, side = RIGHT, padx = 10, pady = 10)
root.mainloop()

2.使用Lambda表达式

在前文程序中，Yellow按钮和Blue按钮执行相同的工作，但是传递的颜色参数不同，其实这是使用Lambda表达式的好时机。我们可以通过Lambda表达式调用相同的方法，但是传递不同参数的方式简化设计

def bColor(bgColor):
	root.config(bg = bgColor)

exitbtn = Button(root, text = "Exit", command = root.destroy)
bluebtn = Button(root, text = "blue", command = lambda:bColor("blue"))
yellowbtn = Button(root, text = "yellow", command = lambda:bColor("yellow"))
redbtn = Button(root, text = "red", command = lambda:bColor("red"))

（效果和之前是一样的）

3.建立含图像的功能按钮

一般功能按钮是用文字当作按钮名称，也可以用图像当作按钮名称。若是使用图像当作按钮，在Button()内可以省略text参数设置按钮名称，但在Button()内要增加images参数设置图像对象。

from tkinter import *

def msgShow():
	label.config(text = "Hello world", bg = "lightyellow", fg = "blue")

root = Tk()
label = Label(root)
image = PhotoImage(file = "2.png")
btn = Button(root, image = image, command = msgShow)
label.pack()
btn.pack()
root.mainloop()

4.简易计算器按钮设计

from tkinter import *

root = Tk()

lab = Label(root, text ="", bg = "yellow", width = 20)
btn7 = Button(root, text = "7", width = 3)
btn8 = Button(root, text = "8", width = 3)
btn9 = Button(root, text = "9", width = 3)
btnc = Button(root, text = "*", width = 3)
btn4 = Button(root, text = "4", width = 3)
btn5 = Button(root, text = "5", width = 3)
btn6 = Button(root, text = "6", width = 3)
btnj = Button(root, text = "-", width = 3)
btn1 = Button(root, text = "1", width = 3)
btn2 = Button(root, text = "2", width = 3)
btn3 = Button(root, text = "3", width = 3)
btna = Button(root, text = "+", width = 3)
btn0 = Button(root, text = "0", width = 8)
btnd = Button(root, text = ".", width = 3)
btne = Button(root, text = "=", width = 3)

lab.grid(row = 0, column = 0, columnspan = 4)
btn7.grid(row =1, column = 0, padx = 5)
btn8.grid(row =1, column = 1, padx = 5)
btn9.grid(row =1, column = 2, padx = 5)
btnc.grid(row =1, column = 3, padx = 5)
btn4.grid(row =2, column = 0, padx = 5)
btn5.grid(row =2, column = 1, padx = 5)
btn6.grid(row =2, column = 2, padx = 5)
btnj.grid(row =2, column = 3, padx = 5)
btn1.grid(row =3, column = 0, padx = 5)
btn2.grid(row =3, column = 1, padx = 5)
btn3.grid(row =3, column = 2, padx = 5)
btna.grid(row =3, column = 3, padx = 5)
btn0.grid(row =4, column = 0, padx = 5, columnspan = 2)
btnd.grid(row =4, column = 2, padx = 5)
btne.grid(row =4, column = 3, padx = 5)

root.mainloop()

5.设计鼠标光标在功能按钮上的的形状

from tkinter import *

def msgShow():
	label.config(text = "Hello world", bg = "lightyellow", fg = "blue")

root = Tk()
label = Label(root)

image = PhotoImage(file = "2.png")
btn = Button(root, image = image, command = msgShow,
	cursor = "plus")

label.pack()
btn.pack()
root.mainloop()

 参考文献：《Python GUI设计tkinter菜鸟编程》洪锦魁著