create table loginuser (
 username varchar(30) NOT NULL PRIMARY KEY ,
 password varchar(16) NOT NULL ,
 email varchar NOT NULL ,
 loginerror int
);

from tkinter import *
import sqlite3
import tkinter.messagebox as messagebox
 
 
class LoginPage:
  """登录界面"""
  def __init__(self, master):
    self.root = master
    self.root.geometry('400x200+600+400')
    self.root.title('项目资源管理平台Alpha0.1')
    self.conn = sqlite3.connect('data/login.db')
    self.username = StringVar()
    self.password = StringVar()
    self.page = Frame(self.root)
    self.creatapage()
 
  def creatapage(self):
    """界面布局"""
    Label(self.page).grid(row=0)
    Label(self.page, text='用户名:').grid(row=1, stick=W, pady=10)
    Entry(self.page, textvariable=self.username).grid(row=1, column=1, stick=E)
    Label(self.page, text='密码:').grid(row=2, stick=W, pady=10)
    Entry(self.page, textvariable=self.password, show='*').grid(row=2, stick=E, column=1)
    Button(self.page, text='登录', command=self.login).grid(row=3, stick=W, pady=10)
    Button(self.page, text='注册账号', command=self.register).grid(row=3, stick=E, column=1)
    self.page.pack()
 
  def login(self):
    """登录功能"""
    curs = self.conn.cursor()
    query = "select username, password, loginerror from loginuser where username='%s'" % self.username.get()
    curs.execute(query) # 返回一个迭代器
    c = curs.fetchall() # 接收全部信息
    if len(c) == 0:
      messagebox.showerror('登录失败', '账户不存在')
    else:
      us, pw, lerror = c[0]
      if lerror >= 3:
        messagebox.showwarning('登录失败', '账户已被锁定')
      elif us == self.username.get() and pw == self.password.get():
        self.conn.close()
        messagebox.showinfo('登录成功', '欢迎：%s' % us)
      else:
        messagebox.showwarning('登录失败', '密码错误')
 
  def register(self):
    """注册功能跳转"""
    self.conn.close()
    self.page.destroy()
    RegisterPage(self.root)
 
 
class RegisterPage:
  """注册界面"""
  def __init__(self, master=None):
    self.root = master
    self.root.title('账号注册')
    self.root.geometry('400x250')
    self.conn = sqlite3.connect('data/login.db')
    self.username = StringVar()
    self.password0 = StringVar() # 第一次输入密码
    self.password1 = StringVar() # 第二次输入密码
    self.email = StringVar()
    self.page = Frame(self.root)
    self.createpage()
 
  def createpage(self):
    """界面布局"""
    Label(self.page).grid(row=0)
    Label(self.page, text="账号:").grid(row=1, stick=W, pady=10)
    Entry(self.page, textvariable=self.username).grid(row=1, column=1, stick=E)
    Label(self.page, text="密码:").grid(row=2, stick=W, pady=10)
    Entry(self.page, textvariable=self.password0, show='*').grid(row=2, column=1, stick=E)
    Label(self.page, text="再次输入:").grid(row=3, stick=W, pady=10)
    Entry(self.page, textvariable=self.password1, show='*').grid(row=3, column=1, stick=E)
    Label(self.page, text="Email*:").grid(row=4, stick=W, pady=10)
    Entry(self.page, textvariable=self.email).grid(row=4, column=1, stick=E)
    Button(self.page, text="返回", command=self.repage).grid(row=5, stick=W, pady=10)
    Button(self.page, text="注册", command=self.register).grid(row=5, column=1, stick=E)
    self.page.pack()
 
  def repage(self):
    """返回登录界面"""
    self.page.destroy()
    self.conn.close()
    LoginPage(self.root)
 
  def register(self):
    """注册"""
    if self.password0.get() != self.password1.get():
      messagebox.showwarning('错误', '密码核对错误')
    elif len(self.username.get()) == 0 or len(self.password0.get()) == 0 or len(self.email.get()) == 0:
      messagebox.showerror("错误", "不能为空")
    else:
      curs = self.conn.cursor()
      query = 'insert into loginuser values (?,?,?,?)'
      val = [self.username.get(), self.password0.get(), self.email.get(), 0]
      try:
        curs.execute(query, val)
        self.conn.commit()
        self.conn.close()
        messagebox.showinfo("成功", "注册成功，按确定返回登录界面")
        self.page.destroy()
        LoginPage(self.root)
      except sqlite3.IntegrityError:
        messagebox.showerror("注册失败", "该账户已存在")
 
 
if __name__ == '__main__':
  root = Tk()
  LoginPage(root)
  root.mainloop()