帮我写一个记账小程序代码，要实现以下内容：（1）使用类实现数据封装； （2）使用tkinter实现界面UI设计。 （3）使用文件保存数据。 （4）能实现用户登陆功能和实现数据的增加、修改、删除和查询操作。 （5）开发平台：Python 3.7以上版本等软件。 （6）项目选题：开题前需向任何教师确认题目及开发难度是否符合课程要求。 （7）作品要求：界面美观易操作，人机交互符合商业应用流程。

好的，下面是一个简单的记账小程序代码，满足你的要求：

import tkinter as tk
import json

class User:
    def __init__(self, username, password):
        self.username = username
        self.password = password

class Account:
    def __init__(self, date, amount, category, note):
        self.date = date
        self.amount = amount
        self.category = category
        self.note = note

class App:
    def __init__(self, master):
        self.master = master
        master.geometry("400x300")
        master.title("记账小程序")

        self.logged_in = False
        self.current_user = None
        self.accounts = []

        # 登录界面
        self.login_frame = tk.Frame(master)
        self.login_frame.pack()

        self.username_label = tk.Label(self.login_frame, text="用户名：")
        self.username_label.grid(row=0, column=0)
        self.username_entry = tk.Entry(self.login_frame)
        self.username_entry.grid(row=0, column=1)

        self.password_label = tk.Label(self.login_frame, text="密码：")
        self.password_label.grid(row=1, column=0)
        self.password_entry = tk.Entry(self.login_frame, show="*")
        self.password_entry.grid(row=1, column=1)

        self.login_button = tk.Button(self.login_frame, text="登录", command=self.login)
        self.login_button.grid(row=2, column=0)

        self.register_button = tk.Button(self.login_frame, text="注册", command=self.register)
        self.register_button.grid(row=2, column=1)

        # 主界面
        self.main_frame = tk.Frame(master)
        self.main_frame.pack()

        self.date_label = tk.Label(self.main_frame, text="日期：")
        self.date_label.grid(row=0, column=0)
        self.date_entry = tk.Entry(self.main_frame)
        self.date_entry.grid(row=0, column=1)

        self.amount_label = tk.Label(self.main_frame, text="金额：")
        self.amount_label.grid(row=1, column=0)
        self.amount_entry = tk.Entry(self.main_frame)
        self.amount_entry.grid(row=1, column=1)

        self.category_label = tk.Label(self.main_frame, text="类别：")
        self.category_label.grid(row=2, column=0)
        self.category_entry = tk.Entry(self.main_frame)
        self.category_entry.grid(row=2, column=1)

        self.note_label = tk.Label(self.main_frame, text="备注：")
        self.note_label.grid(row=3, column=0)
        self.note_entry = tk.Entry(self.main_frame)
        self.note_entry.grid(row=3, column=1)

        self.add_button = tk.Button(self.main_frame, text="添加", command=self.add_account)
        self.add_button.grid(row=4, column=0)

        self.modify_button = tk.Button(self.main_frame, text="修改", command=self.modify_account)
        self.modify_button.grid(row=4, column=1)

        self.delete_button = tk.Button(self.main_frame, text="删除", command=self.delete_account)
        self.delete_button.grid(row=4, column=2)

        self.query_button = tk.Button(self.main_frame, text="查询", command=self.query_account)
        self.query_button.grid(row=4, column=3)

        self.accounts_listbox = tk.Listbox(self.main_frame)
        self.accounts_listbox.grid(row=5, column=0, columnspan=4)

        self.load_data()

    def login(self):
        username = self.username_entry.get()
        password = self.password_entry.get()
        with open("users.json", "r") as f:
            users = json.load(f)
        for user in users:
            if user['username'] == username and user['password'] == password:
                self.logged_in = True
                self.current_user = User(username, password)
                self.show_main_frame()
                break
        else:
            tk.messagebox.showerror("错误", "用户名或密码错误")

    def register(self):
        username = self.username_entry.get()
        password = self.password_entry.get()
        with open("users.json", "r") as f:
            users = json.load(f)
        for user in users:
            if user['username'] == username:
                tk.messagebox.showerror("错误", "用户名已存在")
                break
        else:
            users.append({'username': username, 'password': password})
            with open("users.json", "w") as f:
                json.dump(users, f)
            tk.messagebox.showinfo("提示", "注册成功，请登录")

    def show_main_frame(self):
        if self.logged_in:
            self.login_frame.pack_forget()
            self.main_frame.pack()
            self.master.title(f"记账小程序 - {self.current_user.username}")

    def add_account(self):
        if self.logged_in:
            date = self.date_entry.get()
            amount = self.amount_entry.get()
            category = self.category_entry.get()
            note = self.note_entry.get()
            account = Account(date, amount, category, note)
            self.accounts.append(account)
            self.save_data()
            self.show_accounts()

    def modify_account(self):
        if self.logged_in:
            selection = self.accounts_listbox.curselection()
            if len(selection) == 1:
                index = selection[0]
                account = self.accounts[index]
                account.date = self.date_entry.get()
                account.amount = self.amount_entry.get()
                account.category = self.category_entry.get()
                account.note = self.note_entry.get()
                self.save_data()
                self.show_accounts()

    def delete_account(self):
        if self.logged_in:
            selection = self.accounts_listbox.curselection()
            if len(selection) == 1:
                index = selection[0]
                del self.accounts[index]
                self.save_data()
                self.show_accounts()

    def query_account(self):
        if self.logged_in:
            category = self.category_entry.get()
            filtered_accounts = []
            for account in self.accounts:
                if account.category == category:
                    filtered_accounts.append(account)
            self.show_accounts(filtered_accounts)

    def show_accounts(self, accounts=None):
        if accounts is None:
            accounts = self.accounts
        self.accounts_listbox.delete(0, tk.END)
        for account in accounts:
            text = f"{account.date}   {account.amount}   {account.category}   {account.note}"
            self.accounts_listbox.insert(tk.END, text)

    def save_data(self):
        data = []
        for account in self.accounts:
            data.append({
                'date': account.date,
                'amount': account.amount,
                'category': account.category,
                'note': account.note
            })
        with open(f"{self.current_user.username}.json", "w") as f:
            json.dump(data, f)

    def load_data(self):
        with open("users.json", "r") as f:
            users = json.load(f)
        if len(users) == 0:
            users.append({'username': 'admin', 'password': 'admin'})
            with open("users.json", "w") as f:
                json.dump(users, f)
        with open(f"{self.current_user.username}.json", "a+") as f:
            f.seek(0)
            data = f.read()
            if len(data) == 0:
                data = "[]"
            self.accounts = json.loads(data)
        self.show_accounts()

root = tk.Tk()
app = App(root)
root.mainloop()

这个程序实现了一个简单的记账小应用程序，包括了用户登录、账目增加、修改、删除和查询等功能。数据使用json格式保存在文件中。你可以根据自己的需要进行修改和完善。希望对你有所帮助！