Python PyQt program - Simple text editor

Last update on December 21 2024 07:44:54 (UTC/GMT +8 hours)

Write a Python program to create a simple text editor using PyQt. Allow users to input and save text to a file.

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.

QTextEdit Class: The QTextEdit class provides a widget that is used to edit and display both plain and rich text.

QAction Class: The QAction class provides an abstraction for user commands that can be added to different user interface components.

QFileDialog Class: The QFileDialog class provides a dialog that allow users to select files or directories.

QVBoxLayout Class: The QVBoxLayout class lines up widgets vertically.

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

Sample Solution:

Python Code:

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QTextEdit, QAction, QFileDialog, QVBoxLayout, QWidget

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

        # Set the window properties (title and initial size)
        self.setWindowTitle("Text Editor")
        self.setGeometry(100, 100, 600, 400)  # (x, y, width, height)

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

        # Create a QTextEdit widget for text input
        self.text_edit = QTextEdit()
        self.text_edit.setFontPointSize(14)  # Set font size

        # Create actions for Open and Save
        open_action = QAction("Open", self)
        save_action = QAction("Save", self)

        # Connect actions to methods
        open_action.triggered.connect(self.open_file)
        save_action.triggered.connect(self.save_file)

        # Create a menu bar with File menu
        menu_bar = self.menuBar()
        file_menu = menu_bar.addMenu("File")
        file_menu.addAction(open_action)
        file_menu.addAction(save_action)

        # Create a layout for the central widget and add the QTextEdit
        layout = QVBoxLayout()
        layout.addWidget(self.text_edit)

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

    def open_file(self):
        options = QFileDialog.Options()
        options |= QFileDialog.ReadOnly  # Open file in read-only mode
        file_path, _ = QFileDialog.getOpenFileName(self, "Open File", "", "Text Files (*.txt);;All Files (*)", options=options)
        
        if file_path:
            with open(file_path, 'r') as file:
                self.text_edit.setPlainText(file.read())

    def save_file(self):
        options = QFileDialog.Options()
        options |= QFileDialog.ReadOnly  # Open file in read-only mode
        file_path, _ = QFileDialog.getSaveFileName(self, "Save File", "", "Text Files (*.txt);;All Files (*)", options=options)
        
        if file_path:
            with open(file_path, 'w') as file:
                file.write(self.text_edit.toPlainText())

def main():
    app = QApplication(sys.argv)
    window = TextEditorApp()
    window.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

Explanation:

In the exercise above -

Import the necessary modules.
Create a "QMainWindow" named 'TextEditorApp' with a central widget.
Set the window's title and initial size.
Create a "QTextEdit" widget (text_edit) for text input and customize its appearance by setting the font size.
Create "Open" and "Save" actions and connect them to the open_file and save_file methods, respectively.
Create a menu bar with a "File" menu that contains the "Open" and "Save" actions.
The "open_file()" method opens a file dialog and loads the selected file's contents into QTextEdit.
The "save_file()" method opens a file dialog and saves QTextEdit's contents to the selected file.
In the main function, we create the PyQt application, create an instance of the "TextEditorApp" class, show the window, and run the application's event loop.

Output:

Flowchart:

Python Code Editor:

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