如何用tkinter製作Python的GUI(圖形使用者介面)? 如何做出計算機? eval() 可將字串還原為python指令

from tkinter import * #會造成變數汙染,最好不要這樣用

class Calculator:

  def replaceAndEval(self):

      text = self.e.get()             # “2 + 8 ÷ 2 + 3 x 2”

      text = text.replace(“x”, “*”)   # “2 + 8 ÷ 2 + 3 * 2”

      text = text.replace(“÷”, “/”)   # “2 + 8 / 2 + 3 * 2”

      result = eval( text )

      return result

  def equals(self):

      result = self.replaceAndEval()

      self.allClear()

      self.e.insert(0, result)

  def square(self):

      text = self.replaceAndEval()

      result = text ** 2

      self.allClear()

      self.e.insert(0, result)

  def squareRoot(self):

      text = self.replaceAndEval()

      result = text ** 0.5

      self.allClear()

      self.e.insert(0, result)

  def clearOne(self):

      text = self.e.get()[0:-1]

      self.allClear()

      self.e.insert(0, text)

  def allClear(self):

      self.e.delete(0, END)

  def enterChar(self, symbol):

      self.e.insert(END, symbol)

   

  def __init__(self, window):

“”” 參數window只在__init__()

這個function使用到,

沒有使用self.window承接這個參數

__init__() 的縮排內,

就可以只寫window

不用寫self.window

但若class內的其他function

也要用window這個參數

這種寫法就不一定方便,

要把window也傳去別的function “””

      self.e = Entry(window, width=28)

      self.e.grid(row=0, column=0, columnspan=8)

      self.e.focus()

      Button(window, text=”=”, width=8, command=self.equals).grid(row=4, column=4, columnspan=2)

      Button(window, text=”AC”, width=3, command=self.allClear).grid(row=1, column=4)

      Button(window, text=”C”, width=3, command=self.clearOne).grid(row=1, column=5)

      Button(window, text=”√”, width=3, command=self.squareRoot).grid(row=3, column=4)

      Button(window, text=”x²”, width=3, command=self.square).grid(row=3, column=5)

      Button(window, text=”+”, width=3, command=lambda:self.enterChar(“+”) ).grid(row=4, column=3)

      Button(window, text=”x”, width=3, command=lambda:self.enterChar(“x”) ).grid(row=2, column=3)

      Button(window, text=”-“, width=3, command=lambda:self.enterChar(“-“) ).grid(row=3, column=3)

      Button(window, text=”÷”, width=3, command=lambda:self.enterChar(“÷”) ).grid(row=1, column=3)

      Button(window, text=”%”, width=3, command=lambda:self.enterChar(“%”) ).grid(row=4, column=2)

      Button(window, text=”7″, width=3, command=lambda:self.enterChar(“7”) ).grid(row=1, column=0)

      Button(window, text=”8″, width=3, command=lambda:self.enterChar(“8”) ).grid(row=1, column=1)

      Button(window, text=”9″, width=3, command=lambda:self.enterChar(“9”) ).grid(row=1, column=2)

      Button(window, text=”4″, width=3, command=lambda:self.enterChar(“4”) ).grid(row=2, column=0)

      Button(window, text=”5″, width=3, command=lambda:self.enterChar(“5”) ).grid(row=2, column=1)

      Button(window, text=”6″, width=3, command=lambda:self.enterChar(“6”) ).grid(row=2, column=2)

      Button(window, text=”1″, width=3, command=lambda:self.enterChar(“1”) ).grid(row=3, column=0)

      Button(window, text=”2″, width=3, command=lambda:self.enterChar(“2”) ).grid(row=3, column=1)

      Button(window, text=”3″, width=3, command=lambda:self.enterChar(“3”) ).grid(row=3, column=2)

      Button(window, text=”0″, width=3, command=lambda:self.enterChar(“0”) ).grid(row=4, column=0)

      Button(window, text=”.”, width=3, command=lambda:self.enterChar(“.”) ).grid(row=4, column=1)

      Button(window, text=”(“, width=3, command=lambda:self.enterChar(“(“) ).grid(row=2, column=4)

      Button(window, text=”)”, width=3, command=lambda:self.enterChar(“)”) ).grid(row=2, column=5)

root = Tk()

calc = Calculator(root)

root.mainloop()