如何更改代码，以便在按下按钮时将其显示在输入框中？

Question

我正在Python 3上使用tkinter制作计算器。我已经完成了布局。现在，我试图获取它，以便当我按下按钮时，它会显示在输入框中。例如，如果我先按2按钮，再按+按钮，再按3按钮，则希望它显示在程序顶部的输入框中。

import tkinter
import tkinter.messagebox

class myGUI:

    def __init__(self):
        self.main_window = tkinter.Tk()
        self.main_window.title('Calculator')

        ## Font
        button_font = ('Verdana', 15)
        entry_font = ('Verdana', 36)

        ## Define the frames
        self.frameZero = tkinter.Frame(self.main_window)
        self.frameOne = tkinter.Frame(self.main_window)
        self.frameTwo = tkinter.Frame(self.main_window)
        self.frameThree = tkinter.Frame(self.main_window)
        self.frameFour = tkinter.Frame(self.main_window)
        self.frameFive = tkinter.Frame(self.main_window)

        ## Define the buttons

        self.my_button1 = tkinter.Button(self.frameOne, text='1', command = lambda:btnClick(my_button1), height = 3, width = 7, font = button_font)
        self.my_button2 = tkinter.Button(self.frameOne, text='2', command = lambda:btnClick(my_button2), height = 3, width = 7, font = button_font)
        self.my_button3 = tkinter.Button(self.frameOne, text='3', command = lambda:btnClick(my_button3), height = 3, width = 7, font = button_font)
        self.my_buttonadd = tkinter.Button(self.frameOne, text='+', command = lambda:btnClick(my_buttonadd), height = 3, width = 7, font = button_font)
        self.my_button4 = tkinter.Button(self.frameTwo, text='4', command = lambda:btnClick(my_button4), height = 3, width = 7, font = button_font)
        self.my_button5 = tkinter.Button(self.frameTwo, text='5', command = lambda:btnClick(my_button5), height = 3, width = 7, font = button_font)
        self.my_button6 = tkinter.Button(self.frameTwo, text='6', command = lambda:btnClick(my_button6), height = 3, width = 7, font = button_font)
        self.my_buttonsub = tkinter.Button(self.frameTwo, text='-', command = lambda:btnClick(my_buttonsub), height = 3, width = 7, font = button_font)
        self.my_button7 = tkinter.Button(self.frameThree, text='7', command = lambda:btnClick(my_button7), height = 3, width = 7, font = button_font)
        self.my_button8 = tkinter.Button(self.frameThree, text='8', command = lambda:btnClick(my_button8), height = 3, width = 7, font = button_font)
        self.my_button9 = tkinter.Button(self.frameThree, text='9', command = lambda:btnClick(my_button9), height = 3, width = 7, font = button_font)
        self.my_buttonmult = tkinter.Button(self.frameThree, text='*', command = lambda:btnClick(my_buttonmult), height = 3, width = 7, font = button_font)
        self.my_buttonC = tkinter.Button(self.frameFour, text='C', height = 3, width = 7, font = button_font)
        self.my_button0 = tkinter.Button(self.frameFour, text='0', command = lambda:btnClick(my_button0), height = 3, width = 7, font = button_font)
        self.my_buttonperiod = tkinter.Button(self.frameFour, text='.', command = lambda:btnClick(my_buttonperiod), height = 3, width = 7, font = button_font)
        self.my_buttondiv = tkinter.Button(self.frameFour, text='/', command = lambda:btnClick(my_buttondiv), height = 3, width = 7, font = button_font)
        self.my_buttoncalc = tkinter.Button(self.frameFive, text='Calculate', height = 4, width = 30, font = button_font)

        ## Define the entry area
        self.my_entry = tkinter.Entry(self.frameZero, width = 13, font = entry_font)

        ## Pack the entry area
        self.my_entry.pack(side = 'left')

        ## Pack the buttons
        self.my_button1.pack(side = 'left')
        self.my_button2.pack(side = 'left')
        self.my_button3.pack(side = 'left')
        self.my_buttonadd.pack(side = 'left')
        self.my_button4.pack(side = 'left')
        self.my_button5.pack(side = 'left')
        self.my_button6.pack(side = 'left')
        self.my_buttonsub.pack(side = 'left')
        self.my_button7.pack(side = 'left')
        self.my_button8.pack(side = 'left')
        self.my_button9.pack(side = 'left')
        self.my_buttonmult.pack(side = 'left')
        self.my_buttonC.pack(side = 'left')
        self.my_button0.pack(side = 'left')
        self.my_buttonperiod.pack(side = 'left')
        self.my_buttondiv.pack(side = 'left')
        self.my_buttoncalc.pack(side = 'left')

        ## Pack the frames
        self.frameZero.pack()
        self.frameOne.pack()
        self.frameTwo.pack()
        self.frameThree.pack()
        self.frameFour.pack()
        self.frameFive.pack()

        ## Click button function
        def btnClick(numbers):
            global operator
            operator=operator + str(numbers)
            my_entry = self.set(operator)


        tkinter.mainloop()

my_gui = myGUI()

Answer 1

您需要实现一个tk.StringVar()，该值可以将值存储在计算器屏幕的顶部。要知道的主要方法是此变量的.get()和.set()，这就是访问值（.get()）或更新值（.set()）的方式。您必须使用textvariable参数将其链接到条目。完成设置后，我将btnClick()函数的输入全部更改为字符串。有了所需的字符串（例如“ 12 + 5”）后，就可以使用python内置的eval()函数来计算结果了！请注意，此方法并不安全，因为用户可以根据实现的方式使用它执行任意代码（入侵程序）！您的代码的有效版本如下：

import tkinter
import tkinter.messagebox

class myGUI:

    def __init__(self):
        self.main_window = tkinter.Tk()
        self.main_window.title('Calculator')

        ## Font
        button_font = ('Verdana', 15)
        entry_font = ('Verdana', 36)

        ## Define the frames
        self.frameZero = tkinter.Frame(self.main_window)
        self.frameOne = tkinter.Frame(self.main_window)
        self.frameTwo = tkinter.Frame(self.main_window)
        self.frameThree = tkinter.Frame(self.main_window)
        self.frameFour = tkinter.Frame(self.main_window)
        self.frameFive = tkinter.Frame(self.main_window)

        ## Define the entry area
        self.entry_variable = tkinter.StringVar()
        self.my_entry = tkinter.Entry(self.frameZero, textvariable=self.entry_variable, width=13, font=entry_font)

        ## Define the buttons

        self.my_button1 = tkinter.Button(self.frameOne, text='1', command = lambda:btnClick("1"), height = 3, width = 7, font = button_font)
        self.my_button2 = tkinter.Button(self.frameOne, text='2', command = lambda:btnClick("2"), height = 3, width = 7, font = button_font)
        self.my_button3 = tkinter.Button(self.frameOne, text='3', command = lambda:btnClick("3"), height = 3, width = 7, font = button_font)
        self.my_buttonadd = tkinter.Button(self.frameOne, text='+', command = lambda:btnClick("+"), height = 3, width = 7, font = button_font)
        self.my_button4 = tkinter.Button(self.frameTwo, text='4', command = lambda:btnClick("4"), height = 3, width = 7, font = button_font)
        self.my_button5 = tkinter.Button(self.frameTwo, text='5', command = lambda:btnClick("5"), height = 3, width = 7, font = button_font)
        self.my_button6 = tkinter.Button(self.frameTwo, text='6', command = lambda:btnClick("6"), height = 3, width = 7, font = button_font)
        self.my_buttonsub = tkinter.Button(self.frameTwo, text='-', command = lambda:btnClick("-"), height = 3, width = 7, font = button_font)
        self.my_button7 = tkinter.Button(self.frameThree, text='7', command = lambda:btnClick("7"), height = 3, width = 7, font = button_font)
        self.my_button8 = tkinter.Button(self.frameThree, text='8', command = lambda:btnClick("8"), height = 3, width = 7, font = button_font)
        self.my_button9 = tkinter.Button(self.frameThree, text='9', command = lambda:btnClick("9"), height = 3, width = 7, font = button_font)
        self.my_buttonmult = tkinter.Button(self.frameThree, text='*', command = lambda:btnClick("*"), height = 3, width = 7, font = button_font)
        self.my_buttonC = tkinter.Button(self.frameFour, text='C', height = 3, width = 7, font = button_font)
        self.my_button0 = tkinter.Button(self.frameFour, text='0', command = lambda:btnClick("0"), height = 3, width = 7, font = button_font)
        self.my_buttonperiod = tkinter.Button(self.frameFour, text='.', command = lambda:btnClick("."), height = 3, width = 7, font = button_font)
        self.my_buttondiv = tkinter.Button(self.frameFour, text='/', command = lambda:btnClick("/"), height = 3, width = 7, font = button_font)
        self.my_buttoncalc = tkinter.Button(self.frameFive, text='Calculate', height = 4, width = 30, font = button_font, command=self.calculate)



        ## Pack the entry area
        self.my_entry.pack(side = 'left')

        ## Pack the buttons
        self.my_button1.pack(side = 'left')
        self.my_button2.pack(side = 'left')
        self.my_button3.pack(side = 'left')
        self.my_buttonadd.pack(side = 'left')
        self.my_button4.pack(side = 'left')
        self.my_button5.pack(side = 'left')
        self.my_button6.pack(side = 'left')
        self.my_buttonsub.pack(side = 'left')
        self.my_button7.pack(side = 'left')
        self.my_button8.pack(side = 'left')
        self.my_button9.pack(side = 'left')
        self.my_buttonmult.pack(side = 'left')
        self.my_buttonC.pack(side = 'left')
        self.my_button0.pack(side = 'left')
        self.my_buttonperiod.pack(side = 'left')
        self.my_buttondiv.pack(side = 'left')
        self.my_buttoncalc.pack(side = 'left')

        ## Pack the frames
        self.frameZero.pack()
        self.frameOne.pack()
        self.frameTwo.pack()
        self.frameThree.pack()
        self.frameFour.pack()
        self.frameFive.pack()



        ## Click button function
        def btnClick(number_clicked):
            self.entry_variable.set("{}{}".format(self.entry_variable.get(), number_clicked))

    def calculate(self):
        print("{}".format(eval(str(self.entry_variable.get()))))
        self.entry_variable.set("{}".format(str(eval(str(self.entry_variable.get())))))


my_gui = myGUI()
my_gui.main_window.mainloop() # this should NOT be inside your class like you had it...

总体而言，我喜欢您的框架布局和整体设计。 Lambda函数也很好！欢迎使用StackOverflow。