textbox.py

import sys
from PyQt5.QtWidgets import QMainWindow, QApplication, QWidget, QPushButton, QAction, QLineEdit, QMessageBox
from PyQt5.QtGui import QIcon
from PyQt5.QtCore import pyqtSlot
 
class App(QMainWindow):
 
    def __init__(self):
        super().__init__()
        self.initUI()
 
    def initUI(self):
        self.setWindowTitle('PyQt5 textbox - pythonspot.com')
        self.setGeometry(50,50,1024,1140)
 
        # Create textbox
        self.textbox = QLineEdit(self)
        self.textbox.move(20, 20)
        self.textbox.resize(280,40)
 
        # Create a button in the window
        self.button = QPushButton('Show text', self)
        self.button.move(20,80)
 
        # connect button to function on_click
        self.button.clicked.connect(self.on_click)
        self.show()
 
    @pyqtSlot()
    def on_click(self):
        textboxValue = self.textbox.text()
        QMessageBox.question(self, 'Message - pythonspot.com', "You typed: " + textboxValue, QMessageBox.Ok, QMessageBox.Ok)
        self.textbox.setText("")
 
 
if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())