Question

作为我自学python＆＃39;的一部分，我目前正在创建一个GUI计算器。到目前为止，我已经启动并运行了界面。然而，当我重用计算器（没有重新启动应用程序）时，一个操作是可用的，我得到一个＆＃34; TypeError：＆＃39; str＆＃39;对象不可调用＆＃34;，这表明我没有使用代码。有人可以提供一些有用的指示吗？非常感谢。

def create_widgets(self):
    """Create buttons, text and entry widgets"""
    # Create a text widget
    self.txt = Text(self, width = 40, height = 1, wrap = NONE, pady = 10)
    self.txt.grid(row = 0, column = 0, columnspan = 4)

    # Create number 1
    self.btn1 = Button(self, text = "1", command = lambda: self.insert_number(1), width = 10, pady = 10)
    self.btn1.grid(row = 1, column = 0, columnspan = 1, sticky = W)

    # Create number 2
    self.btn2 = Button(self, text = "2", command = lambda: self.insert_number(2), width = 10, pady = 10)
    self.btn2.grid(row = 1, column = 1, columnspan = 1, sticky = W)

    # Create minus button
    self.btn_minus = Button(self, text = "-", command = lambda: self.operator("-"), width = 10, pady = 10)
    self.btn_minus.grid(row = 1, column = 3, columnspan = 1, sticky = W)

    # Create clear button
    self.btn_clear = Button(self, text = "C", command = self.clear, width = 10, pady = 10)
    self.btn_clear.grid(row = 4, column = 0, columnspan = 1, sticky = W)

    # Create equals
    self.btn_equals = Button(self, text = "=", command = self.equals, width = 10, pady = 10)
    self.btn_equals.grid(row = 4, column = 2, columnspan = 1, sticky = W)

def insert_number(self, number):
    """insert number to the calculator"""
    self.txt.insert(END, number)

def operator(self, action):
    """Make an addition, subtraction, division or multiplication"""
    self.first_number = self.txt.get(0.0, END)
    self.txt.delete(0.0, END)
    self.operator = action

def equals(self):
    self.second_number = self.txt.get(0.0, END)
    self.txt.delete(0.0, END)
    if self.operator == "-": # If operator is minus
        self.answer = int(self.first_number) - int(self.second_number)
        self.txt.insert(0.0, self.answer)

def clear(self):
    self.txt.delete(0.0, END)

按下＆＃39;减号＆＃39>时出现错误信息按钮第二次：

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Python34\lib\tkinter\__init__.py", line 1533, in __call__
    return self.func(*args)
  File "C:\Users\Dan\Documents\Coding\Python Projects\Book\calculator.py", line 33, in <lambda>
self.btn_minus = Button(self, text = "-", command = lambda: self.operator("-"), width = 10, pady = 10)
TypeError: 'str' object is not callable

Answer 1

您的错误在于：self.operator = action

基本上，您将self.operator的值从方法设置为字符串，因此当您调用self.operator('-')时，您尝试执行' - '并获取TypeError。我建议将self.operator = action更改为

global operator
operator = action

并将if self.operator == "-":替换为if operator == "-":

我正在创建的计算器上的Python TypeError

1 个答案: