python 实现一个图形界面的汇率计算器

import requests
from tkinter import *
import tkinter as tk
from tkinter import ttk


class RealTimeCurrencyConverter():
  def __init__(self,url):
      self.data = requests.get(url).json()
      self.currencies = self.data[\'rates\']

  def convert(self, from_currency, to_currency, amount): 
    initial_amount = amount 
    if from_currency != \'USD\' : 
      amount = amount / self.currencies[from_currency] 
 
    
    amount = round(amount * self.currencies[to_currency], 4) 
    return amount

class App(tk.Tk):

  def __init__(self, converter):
    tk.Tk.__init__(self)
    self.title = \'Currency Converter\'
    self.currency_converter = converter

    
    self.geometry(\"500x200\")
    
    
    self.intro_label = Label(self, text = \'Welcome to Real Time Currency Convertor\', fg = \'blue\', relief = tk.RAISED, borderwidth = 3)
    self.intro_label.config(font = (\'Courier\',15,\'bold\'))

    self.date_label = Label(self, text = f\"1 Indian Rupee equals = {self.currency_converter.convert(\'INR\',\'USD\',1)} USD \\n Date : {self.currency_converter.data[\'date\']}\", relief = tk.GROOVE, borderwidth = 5)

    self.intro_label.place(x = 10 , y = 5)
    self.date_label.place(x = 160, y= 50)

    
    valid = (self.register(self.restrictNumberOnly), \'%d\', \'%P\')
    self.amount_field = Entry(self,bd = 3, relief = tk.RIDGE, justify = tk.CENTER,validate=\'key\', validatecommand=valid)
    self.converted_amount_field_label = Label(self, text = \'\', fg = \'black\', bg = \'white\', relief = tk.RIDGE, justify = tk.CENTER, width = 17, borderwidth = 3)

    
    self.from_currency_variable = StringVar(self)
    self.from_currency_variable.set(\"INR\") 
    self.to_currency_variable = StringVar(self)
    self.to_currency_variable.set(\"USD\") 

    font = (\"Courier\", 12, \"bold\")
    self.option_add(\'*TCombobox*Listbox.font\', font)
    self.from_currency_dropdown = ttk.Combobox(self, textvariable=self.from_currency_variable,values=list(self.currency_converter.currencies.keys()), font = font, state = \'readonly\', width = 12, justify = tk.CENTER)
    self.to_currency_dropdown = ttk.Combobox(self, textvariable=self.to_currency_variable,values=list(self.currency_converter.currencies.keys()), font = font, state = \'readonly\', width = 12, justify = tk.CENTER)

    
    self.from_currency_dropdown.place(x = 30, y= 120)
    self.amount_field.place(x = 36, y = 150)
    self.to_currency_dropdown.place(x = 340, y= 120)
    
    self.converted_amount_field_label.place(x = 346, y = 150)
    
    
    self.convert_button = Button(self, text = \"Convert\", fg = \"black\", command = self.perform) 
    self.convert_button.config(font=(\'Courier\', 10, \'bold\'))
    self.convert_button.place(x = 225, y = 135)

  def perform(self):
    amount = float(self.amount_field.get())
    from_curr = self.from_currency_variable.get()
    to_curr = self.to_currency_variable.get()

    converted_amount = self.currency_converter.convert(from_curr,to_curr,amount)
    converted_amount = round(converted_amount, 2)

    self.converted_amount_field_label.config(text = str(converted_amount))
  
  def restrictNumberOnly(self, action, string):
    regex = re.compile(r\"[0-9,]*?(\\.)?[0-9,]*$\")
    result = regex.match(string)
    return (string == \"\" or (string.count(\'.\') <= 1 and result is not None))

if __name__ == \'__main__\':
  url = \'https://api.exchangerate-api.com/v4/latest/USD\'
  converter = RealTimeCurrencyConverter(url)

  App(converter)
  mainloop()