用kivy写一个手机记账app

好的，下面是一个简单的用Kivy写的手机记账App的代码示例。这个App允许用户输入账单明细、日期和费用，并将其保存到本地文件中。

import os
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ObjectProperty
from kivy.utils import get_color_from_hex
from kivy.core.window import Window


class AddExpenseForm(BoxLayout):
    expense_title = ObjectProperty()
    expense_date = ObjectProperty()
    expense_amount = ObjectProperty()

    def __init__(self, **kwargs):
        super(AddExpenseForm, self).__init__(**kwargs)

    def validate_input(self):
        if not self.expense_title.text:
            self.expense_title.hint_text = "Title is required"
            self.expense_title.hint_text_color = get_color_from_hex('#FF0000')
            return False
        elif not self.expense_date.text:
            self.expense_date.hint_text = "Date is required"
            self.expense_date.hint_text_color = get_color_from_hex('#FF0000')
            return False
        elif not self.expense_amount.text:
            self.expense_amount.hint_text = "Amount is required"
            self.expense_amount.hint_text_color = get_color_from_hex('#FF0000')
            return False
        else:
            return True

    def save_expense(self):
        if self.validate_input():
            expense_data = self.expense_title.text + ',' + self.expense_date.text + ',' + self.expense_amount.text
            with open("expenses.txt", "a") as f:
                f.write(expense_data + "\n")
            self.expense_title.text = ""
            self.expense_date.text = ""
            self.expense_amount.text = ""


class ExpenseManager(App):
    def build(self):
        Window.clearcolor = get_color_from_hex('#FFFFFF')
        if not os.path.exists("expenses.txt"):
            open("expenses.txt", "w").close()
        return AddExpenseForm()


if __name__ == '__main__':
    ExpenseManager().run()

在这个App中，我们使用了一个BoxLayout来创建一个简单的表单，用于输入账单明细、日期和费用。当用户点击“Save”按钮时，我们会验证用户输入是否有效，并将账单数据保存到本地文件中。

运行这个App，你将看到一个简单的表单，输入账单信息并点击“Save”按钮即可保存。