Python PyQt6 GUI

import sys

from PyQt6.QtWidgets import QApplication, QWidget, QLineEdit, QPushButton, QTextEdit, QVBoxLayout

from PyQt6.QtGui import QIcon





class App(QWidget):

    def __init__(self):

        super().__init__()

        self.setWindowTitle("Python GUI")

        self.setFixedSize(800, 600) # width, height

        self.setWindowIcon(QIcon('icon.png'))

        

        layout = QVBoxLayout()

        self.setLayout(layout)

        

        self.inputField = QLineEdit()

        self.textField = QTextEdit() # multiline text input

        self.button = QPushButton("Greet")

        self.button.clicked.connect(self.sayHi)

        layout.addWidget(self.inputField)

        layout.addWidget(self.textField)

        layout.addWidget(self.button)

    

    def sayHi(self):

        inputText = self.inputField.text()

        self.textField.setText(f"Hi, {inputText}!")





if __name__ == "__main__":

    app = QApplication(sys.argv)

    app.setStyle("Fusion") # ['Breeze', 'Oxygen', 'QtCurve', 'Windows', 'Fusion']

    app.setStyleSheet('''

                      QPushButton { font-size: 20px; }

                      ''')

    window = App()

    window.show()

    sys.exit(app.exec())