Creating a text display application with PyQt

Python PyQt Basic: Exercise-4 with Solution

Write a Python program that creates a PyQt application with a QLineEdit widget and a QPushButton. When the button is clicked, it should display the text entered in QLineEdit

Note:
The QLineEdit widget is a one-line text editor.
The QPushButton widget provides a command button.

From doc.qt.io:

QApplication Class: The QApplication class manages the GUI application's control flow and main settings.

QMainWindow Class: The QMainWindow class provides a main application window.

QLabel Class: The QLabel widget provides a text or image display.

QLineEdit Class: A line edit allows the user to enter and edit a single line of plain text with a useful collection of editing functions, including undo and redo, cut and paste, and drag and drop.

QPushButton: The push button, or command button, is perhaps the most commonly used widget in any graphical user interface. Push (click) a button to command the computer to perform some action, or to answer a question. Typical buttons are OK, Apply, Cancel, Close, Yes, No and Help.

QVBoxLayout Class: This class is used to construct vertical box layout objects.

QWidget: The QWidget class is the base class of all user interface objects.

Sample Solution:

Python Code:

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QLineEdit, QPushButton, QVBoxLayout, QWidget

class TextDisplayApp(QMainWindow):
    def __init__(self):
        super().__init__()

        # Set the window properties (title and initial size)
        self.setWindowTitle("Text Display Application")
        self.setGeometry(100, 100, 400, 200)  # (x, y, width, height)

        # Create a central widget for the main window
        central_widget = QWidget()
        self.setCentralWidget(central_widget)

        # Create widgets (QLineEdit, QPushButton, and QLabel)
        self.text_edit = QLineEdit()
        self.display_button = QPushButton("Click here to display Text")
        self.result_label = QLabel("")

        # Create a vertical layout
        layout = QVBoxLayout()

        # Add widgets to the layout
        layout.addWidget(self.text_edit)
        layout.addWidget(self.display_button)
        layout.addWidget(self.result_label)

        # Set the layout for the central widget
        central_widget.setLayout(layout)

        # Connect the button click event to the display_text function
        self.display_button.clicked.connect(self.display_text)

    def display_text(self):
        # Get the text from the QLineEdit and display it in the QLabel
        entered_text = self.text_edit.text()
        self.result_label.setText(f"Input Text: {entered_text}")

def main():
    # Create a PyQt application
    app = QApplication(sys.argv)

    # Create an instance of the TextDisplayApp class
    window = TextDisplayApp()

    # Show the window
    window.show()

    # Run the application's event loop
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

Explanation:

In the exercise above -

• Inport the necessary modules.
• Create a custom "TextDisplayApp" class that inherits from "QMainWindow".
• Inside the class, we create the window and widgets (QLineEdit, QPushButton, and QLabel) as well as set their properties and layout.
• Connect the button's click event to the display_text method, which retrieves the text from the 'QLineEdit' and displays it in the 'QLabel'.
• Create an instance of 'TextDisplayApp', show the window, and begin the application's event loop in the main function.

Output:

Flowchart:

Python Code Editor:

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