Python PyQt program - Simple text editor

Python PyQt Widgets: Exercise-3 with Solution

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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