curr_exchange.py

import requests
import sys
from PyQt5.QtGui import QPalette, QFont
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QVBoxLayout, QListWidget, QLineEdit, QHBoxLayout, QMainWindow,QComboBox
class curr_converter(QWidget):
    def __init__(self):   
        super().__init__()
        self.setWindowTitle("Currency Converter")
        self.setStyleSheet("background-color: #58A4B0;")
        self.setFixedWidth(400)
        self.layout = QVBoxLayout()
        self.setLayout(self.layout)

        curr_data, curr_list = self.load_api() 
        self.curr_data = curr_data #curr data do converta

        lists = self.lists(curr_list)
        inputs = self.input_fields()

        self.layout.addLayout(lists) #dodanie listy i pol na inputy
        self.layout.addLayout(inputs)

        self.output_field = inputs.itemAt(1).widget() #dostep do pól
        self.input_field = inputs.itemAt(0).widget()
        self.from_list = lists.itemAt(0).widget()
        self.to_list = lists.itemAt(1).widget()

        self.input_field.textChanged.connect(self.convert) #polaczenie pola z convertem


    def lists(self, curr_list):  #listy horyznotalnie 
        from_list = QComboBox() #drop down
        from_list.setStyleSheet("background-color: #BAC1B8; color: black; border-radius:5px;")
        from_list.addItems(curr_list)
        from_list.setCurrentIndex(curr_list.index('USD'))
        to_list = QComboBox()
        to_list.setStyleSheet("background-color: #BAC1B8; color: black; border-radius:5px;")
        to_list.addItems(curr_list)
        to_list.setCurrentIndex(curr_list.index('PLN'))

        layout = QHBoxLayout()
        layout.addWidget(from_list)
        layout.addWidget(to_list)
        return layout

    def input_fields(self):   #inputy horyzontalnie
        input_f = QLineEdit()
        input_f.setStyleSheet("background-color: #FFFFFF; color: black; border-radius:5px;")
        output_f = QLineEdit()
        output_f.setStyleSheet("background-color: #FFFFFF; color: black; border-radius:5px;")
        output_f.setReadOnly(True)  #wynik
        
        layout = QHBoxLayout()
        layout.addWidget(input_f)
        layout.addWidget(output_f)
        return layout

    def convert(self): 
        from_curr=self.from_list.currentText() #listy
        to_curr=self.to_list.currentText() 
        amount=self.input_field.text() #pobranie wartosci z inputu

        try:
            amount = float(amount)
        except ValueError:
            self.output_field.setText("BŁĘDNY FORMAT")
            return
        if from_curr == to_curr:
            self.output_field.setText(str(amount)) #bez obliczania dla tych samych walut
            return
        
        from_rate = self.curr_data[from_curr] #obliczanie
        to_rate = self.curr_data[to_curr]
        result = amount / from_rate * to_rate
        self.output_field.setText(str(result)) #wstawienie w output

    def load_api(self):
        url = 'https://api.freecurrencyapi.com/v1/latest?apikey=fca_live_ybAM6h8asWboJSTGOSUy9TLPda85XRCXKRst6SoX' #wczytanie danych z api
        response = requests.get(url)
        curr_data = response.json()['data']
        curr_list=list(curr_data.keys())
        return curr_data, curr_list



if __name__== "__main__":
  application=QApplication(sys.argv)
  win= curr_converter()
  win.show()
  sys.exit(application.exec_())