from tkinter import *
user_login={'aaa':'123456','bbb':'888888','ccc':'333333'}
#定义登录次数
count=0
def login():
    global count
    username =entry_username.get()
    if username not in user_login:
        label_message.config(text='账号错误!')
    else:
        password =entry_password.get ()
        if (password==user_login [username]):
            label_message.config(text ='登录成功！')
        else:
            label_message.config(text='密码错误！还可以尝试{}次'.format(2-count))
            count =count +1
            if count ==3:
                label_message.config(text ='登录失败！')
                btn_login.config(state="disabled")
#创建主窗口
window =Tk()
window.title("用户登录")
window.geometry("300x200")
#创建标签和输入框
label_username =Label(window,text="账号：")
label_username.pack()
entry_username =Entry(window)
entry_username.pack()
label_password=Label(window,text="密码：")
label_password.pack()
entry_password =Entry(window, show ='*')
entry_password.pack()
#创建登录按钮和消息提示标签
btn_login=Button(window, text="登录",command=login)
btn_login.pack()
label_message =Label (window, text ="")
label_message.pack()
#运行主循环
window.mainloop()