Python tkinter属性错误_Python_Tkinter

Python tkinter属性错误

python tkinter

Python tkinter属性错误,python,tkinter,Python,Tkinter,我使用BankAccount类创建GUI，允许用户存款、取款和查看余额这是银行账户类别代码： class BankAccount(object): """ creates a bank account with the owner's name and a balance """ def __init__(self, name, balance = 0): self.__name = name self.__balance =

我使用BankAccount类创建GUI，允许用户存款、取款和查看余额

这是银行账户类别代码：

class BankAccount(object):
    """ creates a bank account with the 
        owner's name and a balance """
    def __init__(self, name, balance = 0):
        self.__name = name
        self.__balance = balance

    def getName(self):
        """ returns the owner's name """
        return self.__name

    def getBalance(self):
        """ returns the current balance """
        return round(self.__balance, 2)

    def deposit(self, amount):
        """ deposits amount into the account """
        self.__balance += amount

    def withdraw(self, amount):
        """ withdraws amount from the account
            returns 'overdrawn' if balance is too low """
        if self.__balance >= amount:
            self.__balance -= amount
        else:
            return 'overdrawn'

    def __str__(self):
        """ return a string representation of the account """
        return self.__name + ' has a balance of $' + str(round(self.__balance, 2))

这是GUI代码：

from tkinter import *
from bankAccountClass import BankAccount




class bankAccountGUI(Frame):
    def __init__(self):
        """Set up the GUI"""
        self.__balance= 0
        Frame.__init__(self)
        self.master.title('Bank Account')
        self.grid()

        depositLabel = Label(self, text= "Make Deposit")
        depositLabel.grid(row = 0, column = 0)
        self.depositVar= DoubleVar()
        depositEntry = Entry(self, textvariable= self.depositVar)
        depositEntry.grid(row = 0, column = 1)

        withdrawLabel= Label(self, text= "Make Withdrawal")
        withdrawLabel.grid(row = 1, column = 0)
        self.withdrawVar = DoubleVar()
        withdrawEntry= Entry(self, textvariable= self.withdrawVar)
        withdrawEntry.grid(row = 1, column = 1)


        button_1= Button(self, text = "Enter", command = self.deposit)
        button_1.grid(row = 0, column = 2)

        button_2= Button(self, text = "Enter", command = self.withdrawal)
        button_2.grid(row = 1, column = 2)


    def deposit(self):
        """event handler for button_1"""
        try:
            amount= self.depositVar.get()
            balance= BankAccount.getBalance(self)
            if amount <= 0:
                messagebox.showerror(message= 'Deposit must be greater than 0')
            else:
                balance= BankAccount.deposit(self, amount)
                messagebox.showinfo(title= "Current Balance",
                                    message= "$" + self.balance,
                                    parent= self)
        except ValueError:
            messagebox.showerror(message= "Invalid deposit amount")


    def withdrawal(self):
        """event handler for button_2"""
        try:
            amount= self.withdrawVar.get()
            balance= BankAccount.getBalance(self)
            if amount > self.balance:
                messagebox.showerror(message= "Insufficient funds")
            else:
                balance= BankAccount.withdraw(self, amount)
                messagebox.showinfo(title= "Current Balance",
                                    message= "$" + self.balance,
                                    parent= self)
        except ValueError:
            messagebox.showerror(message= "Invalid withdrawal amount")

def main():
    """instantiate and pop up the window"""
    bankAccountGUI().mainloop()

要了解错误消息中提到的变量

\u BankAccount\u balance

，有关双下划线和“名称混乱”的使用，请参见：

。。。由于类私有成员有一个有效的用例（即避免名称与子类定义的名称发生名称冲突），因此对这种称为名称混乱的机制的支持有限。格式为

\uuuu spam

（至少两个前导下划线，最多一个尾随下划线）的任何标识符都将以文本形式替换为

\u classname\uuuuu spam

，其中classname是当前类名，前导下划线已去除

其公认的答案也提供了信息

解决此问题的最简单方法是从类变量名中删除所有前导下划线。或者，您可以将

BankAccount.getBalance（）

函数中的

self.\u balance

更改为

self.\u BankAccount\u balance

编辑：您还将

bankAccountGUI

对象作为

getBalance

函数中的参数传递，作为

self

。它应该是

balance=BankAccount.getBalance（）

，而不是

self

，以理解错误消息中提到的变量

\u BankAccount\u balance