import sys
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *


class MyWindow(QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("Kantor")
        grid = QGridLayout()
        self.setLayout(grid)

        label1 = QLabel("Kwota PLN:")
        label1.setFont(QFont("Calibri", 16))
        grid.addWidget(label1, 1, 0)

        label2 = QLabel("Kwota USD/Euro")
        label2.setFont(QFont("Calibri", 16))
        grid.addWidget(label2, 2, 0)

        self.oblicz_button = QPushButton("Oblicz", self)
        self.oblicz_button.clicked.connect(self.oblicz)
        grid.addWidget(self.oblicz_button, 3, 1)

        self.textbox1 = QTextEdit('10', self)
        grid.addWidget(self.textbox1, 1, 1)
        self.textbox2 = QTextEdit('', self)
        grid.addWidget(self.textbox2, 2, 1)

        self.waluta_radio = QButtonGroup()

        self.radiobutton3 = QRadioButton("USD")
        self.radiobutton3.setChecked(True)
        self.radiobutton3.toggled.connect(self.oblicz)
        grid.addWidget(self.radiobutton3, 2, 2)

        self.radiobutton4 = QRadioButton("Euro")
        self.radiobutton4.setChecked(False)
        self.radiobutton4.toggled.connect(self.oblicz)
        grid.addWidget(self.radiobutton4, 2, 3)

        self.waluta_radio.addButton(self.radiobutton3)
        self.waluta_radio.addButton(self.radiobutton4)

    def oblicz(self):
        waluta = float(self.textbox1.toPlainText())
        if self.radiobutton3.isChecked():
            waluta = waluta * 4.30

        if self.radiobutton4.isChecked():
            waluta = waluta * 4.60

        self.textbox2.setText(str(waluta))

if __name__ == '__main__':
    app = QApplication(sys.argv)
    MyWindow = MyWindow()
    MyWindow.resize(640, 480)
    MyWindow.show()
    sys.exit(app.exec_())