Creating a Multi-Themed App Using PyQt and QtDesigner Tutorial

In this tutorial, we will walk through creating a multi-themed app using PyQt and QtDesigner. PyQt is a set of Python bindings for the Qt application framework and QtDesigner is a graphical user interface design tool for creating and designing Qt applications.

For this tutorial, we will create a simple app that allows users to switch between different themes for the application. We will provide users with various color schemes to choose from, and update the app’s appearance based on their selection.

Let’s get started!

Step 1: Install PyQt and QtDesigner
First, you will need to install PyQt and QtDesigner. You can install PyQt using pip by running the following command:

pip install PyQt5

You can also install QtDesigner by installing the Qt Creator IDE, which includes QtDesigner. You can download Qt Creator from the Qt website.

Step 2: Design the App UI in QtDesigner
Open QtDesigner and create a new main window form. You can add buttons, labels, and other widgets to design the UI of the app. For our multi-themed app, we will add a label to display the theme name, a combo box to select different themes, and a button to apply the selected theme.

Step 3: Set Up the Project in Python
Create a new Python file and import the necessary modules:

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow

Create a class for the main window of the app and initialize it with the UI layout created in QtDesigner:

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

        # Load the UI file created in QtDesigner
        self.setWindowTitle("Multi-Themed App")
        self.resize(400, 300)

Step 4: Implement the Theme Switching Functionality
Next, we will implement the functionality to switch between different themes in the app. We will define a dictionary with different color schemes and update the app’s appearance based on the selected theme:

themes = {
    "Light": {"background-color": "#FFFFFF", "text-color": "#000000"},
    "Dark": {"background-color": "#000000", "text-color": "#FFFFFF"},
    "Blue": {"background-color": "#3498DB", "text-color": "#FFFFFF"},
}

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

        # Load the UI file created in QtDesigner
        self.setWindowTitle("Multi-Themed App")
        self.resize(400, 300)

        # Add widgets to the main window
        self.label = QLabel("Select Theme:", self)
        self.label.move(50, 50)

        self.theme_combo = QComboBox(self)
        self.theme_combo.addItems(themes.keys())
        self.theme_combo.move(150, 50)

        self.apply_btn = QPushButton("Apply Theme", self)
        self.apply_btn.move(50, 100)

        # Connect the apply button to the apply_theme method
        self.apply_btn.clicked.connect(self.apply_theme)

    def apply_theme(self):
        theme_name = self.theme_combo.currentText()
        theme = themes[theme_name]

        self.setStyleSheet(f"background-color: {theme['background-color']}; color: {theme['text-color']};")

Step 5: Run the App
Finally, create an instance of the MainWindow class and run the application:

if __name__ == "__main__":
    app = QApplication(sys.argv)
    main_window = MainWindow()
    main_window.show()
    sys.exit(app.exec_())

Now you have a multi-themed app that allows users to switch between different color schemes. You can expand on this tutorial by adding more themes, customizing the app’s appearance further, and adding additional functionality to the app.

I hope this tutorial was helpful for creating a multi-themed app using PyQt and QtDesigner. Thank you for reading!