**Course Title:** PyQt6 Application Development **Section Title:** Building Responsive and Adaptive UIs **Topic:** Using QStackedWidget and dynamic layouts **Overview** In this topic, we will explore the QStackedWidget and dynamic layouts in PyQt6. QStackedWidget is a container class that manages a set of widgets and displays only one at a time, while dynamic layouts allow you to arrange widgets in a flexible and responsive manner. By mastering these concepts, you'll be able to create robust, adaptable, and user-friendly interfaces. **What is QStackedWidget?** QStackedWidget is a subclass of QWidget that manages a set of widgets and displays only one at a time. This allows you to implement multiple pages or views in a single window, and switch between them seamlessly. QStackedWidget is particularly useful in applications with multiple modes or workflows. **Creating a QStackedWidget** To create a QStackedWidget, you simply need to instantiate the class and add your widgets to it using the `addWidget()` method. Here's an example: ```python import sys from PyQt6.QtWidgets import QApplication, QStackedWidget, QWidget, QVBoxLayout, QPushButton class Window(QWidget): def __init__(self): super().__init__() self.stack = QStackedWidget() self.layout = QVBoxLayout() self.layout.addWidget(self.stack) # Create pages page1 = QWidget() page1_layout = QVBoxLayout() page1_layout.addWidget(QPushButton("Page 1")) page1.setLayout(page1_layout) page2 = QWidget() page2_layout = QVBoxLayout() page2_layout.addWidget(QPushButton("Page 2")) page2.setLayout(page2_layout) self.stack.addWidget(page1) self.stack.addWidget(page2) # Add navigation buttons nav_layout = QVBoxLayout() nav_button = QPushButton("Go to Page 2") nav_button.clicked.connect(lambda: self.stack.setCurrentIndex(1)) nav_layout.addWidget(nav_button) nav_button = QPushButton("Go to Page 1") nav_button.clicked.connect(lambda: self.stack.setCurrentIndex(0)) nav_layout.addWidget(nav_button) self.layout.addLayout(nav_layout) self.setLayout(self.layout) if __name__ == "__main__": app = QApplication(sys.argv) window = Window() window.show() sys.exit(app.exec()) ``` In this example, we create a QStackedWidget and add two pages to it. We then add navigation buttons to switch between the pages. **Using Dynamic Layouts** Dynamic layouts allow you to arrange widgets in a flexible and responsive manner. In PyQt6, you can use the `QLayout` class to create dynamic layouts. There are several subclasses of `QLayout`, including: * `QVBoxLayout`: arranges widgets vertically * `QHBoxLayout`: arranges widgets horizontally * `QGridLayout`: arranges widgets in a grid * `QFormLayout`: arranges widgets in a form-like layout To create a dynamic layout, you simply need to create a layout object and add your widgets to it. Here's an example: ```python import sys from PyQt6.QtWidgets import QApplication, QWidget, QVBoxLayout, QPushButton, QLineEdit class Window(QWidget): def __init__(self): super().__init__() self.layout = QVBoxLayout() self.setLayout(self.layout) # Create a dynamic layout with a line edit and a button line_edit = QLineEdit() button = QPushButton("Click me!") self.layout.addWidget(line_edit) self.layout.addWidget(button) # Add a stretch to the layout self.layout.addStretch() if __name__ == "__main__": app = QApplication(sys.argv) window = Window() window.show() sys.exit(app.exec()) ``` In this example, we create a QVBoxLayout and add a line edit and a button to it. We also add a stretch to the layout to make it responsive. **Tips and Best Practices** * Use QStackedWidget to manage multiple pages or views in a single window. * Use dynamic layouts to arrange widgets in a flexible and responsive manner. * Use the `addWidget()` method to add widgets to a layout. * Use the `addStretch()` method to make a layout responsive. **Example Code** * [QStackedWidget example](https://github.com/PyQt6-Tutorials/pyqt6/tree/main/examples/qstackedwidget) * [Dynamic layouts example](https://github.com/PyQt6-Tutorials/pyqt6/tree/main/examples/layouts) **Conclusion** In this topic, we explored QStackedWidget and dynamic layouts in PyQt6. By mastering these concepts, you'll be able to create robust, adaptable, and user-friendly interfaces. Remember to use the `addWidget()` method to add widgets to a layout, and the `addStretch()` method to make a layout responsive. **What's Next?** In the next topic, we'll cover implementing QSplitter and QTabWidget for multi-view interfaces. **Leave a Comment/Ask for Help** If you have any questions or need help with the material, please leave a comment below. We'll get back to you as soon as possible. **Resources** * [PyQt6 documentation](https://www.riverbankcomputing.com/software/pyqt/)