**Course Title:** PyQt6 Application Development **Section Title:** Advanced Widgets and Forms **Topic:** Advanced widgets: QComboBox, QListWidget, QTableWidget, QTreeView In this topic, we will explore some of the advanced widgets available in PyQt6. These widgets are designed to handle complex data and provide a more sophisticated user interface for your applications. We will cover the QComboBox, QListWidget, QTableWidget, and QTreeView widgets, providing in-depth explanations, examples, and practical takeaways to help you master these advanced widgets. ### QComboBox The QComboBox widget is a drop-down list of items that allows the user to select one item from the list. You can use QComboBox to provide a list of options to the user, such as a list of countries, currencies, or languages. **Example Code:** ```python import sys from PyQt6.QtWidgets import QApplication, QWidget, QComboBox, QLabel class Example(QWidget): def __init__(self): super().__init__() self.initUI() def initUI(self): self.setGeometry(300, 300, 300, 200) self.setWindowTitle('QComboBox') self.combo = QComboBox(self) self.combo.addItem('Option 1') self.combo.addItem('Option 2') self.combo.addItem('Option 3') self.combo.move(50, 50) label = QLabel(self) label.move(50, 100) label.setText("Select an option") self.combo.currentTextChanged.connect(lambda text: label.setText("Selected option: " + text)) self.show() if __name__ == '__main__': app = QApplication(sys.argv) ex = Example() sys.exit(app.exec()) ``` In this example, we create a QComboBox widget and add three items to it. We then connect the currentTextChanged signal to a slot that updates the label text with the selected option. ### QListWidget The QListWidget widget is a list of items that can be scrolled vertically. You can use QListWidget to display a list of items, such as a list of files or a list of tasks. **Example Code:** ```python import sys from PyQt6.QtWidgets import QApplication, QWidget, QListWidget, QListWidgetItem class Example(QWidget): def __init__(self): super().__init__() self.initUI() def initUI(self): self.setGeometry(300, 300, 300, 200) self.setWindowTitle('QListWidget') self.listwidget = QListWidget(self) self.listwidget.move(50, 50) items = ['Item 1', 'Item 2', 'Item 3', 'Item 4', 'Item 5'] for item in items: self.listwidget.addItem(QListWidgetItem(item)) self.show() if __name__ == '__main__': app = QApplication(sys.argv) ex = Example() sys.exit(app.exec()) ``` In this example, we create a QListWidget widget and add five items to it. We then display the list of items. ### QTableWidget The QTableWidget widget is a table of items that can be scrolled vertically and horizontally. You can use QTableWidget to display a table of data, such as a spreadsheet or a database table. **Example Code:** ```python import sys from PyQt6.QtWidgets import QApplication, QWidget, QTableWidget, QTableWidgetItem, QVBoxLayout class Example(QWidget): def __init__(self): super().__init__() self.initUI() def initUI(self): self.setGeometry(300, 300, 300, 200) self.setWindowTitle('QTableWidget') layout = QVBoxLayout() tablewidget = QTableWidget(5, 2, self) layout.addWidget(tablewidget) items = ['Item 1', 'Item 2', 'Item 3', 'Item 4', 'Item 5'] for i in range(5): tablewidget.setItem(i, 0, QTableWidgetItem(items[i])) tablewidget.setItem(i, 1, QTableWidgetItem('Description ' + str(i+1))) layout.addWidget(tablewidget) self.setLayout(layout) self.show() if __name__ == '__main__': app = QApplication(sys.argv) ex = Example() sys.exit(app.exec()) ``` In this example, we create a QTableWidget widget with 5 rows and 2 columns. We then add items to the table. ### QTreeView The QTreeView widget is a hierarchical list of items that can be scrolled vertically. You can use QTreeView to display a tree of items, such as a file system or a database schema. **Example Code:** ```python import sys from PyQt6.QtWidgets import QApplication, QWidget, QTreeView, QFileSystemModel from PyQt6.QtCore import QSortFilterProxyModel class Example(QWidget): def __init__(self): super().__init__() self.initUI() def initUI(self): self.setGeometry(300, 300, 300, 200) self.setWindowTitle('QTreeView') model = QFileSystemModel() model.setRootPath('') proxy = QSortFilterProxyModel() proxy.setSourceModel(model) treeview = QTreeView(self) treeview.setModel(proxy) treeview.move(50, 50) treeview.setRootIndex(proxy.mapFromSource(model.index('C:/'))) self.show() if __name__ == '__main__': app = QApplication(sys.argv) ex = Example() sys.exit(app.exec()) ``` In this example, we create a QFileSystemModel and a QSortFilterProxyModel to filter the file system. We then create a QTreeView widget and set its model to the proxy model. We then display the file system. ### Conclusion In this topic, we have covered some of the advanced widgets available in PyQt6. We have explored the QComboBox, QListWidget, QTableWidget, and QTreeView widgets and provided examples of how to use them. These widgets provide a powerful way to create complex user interfaces and display data in your applications. **Key Takeaways:** * QComboBox is a drop-down list of items that allows the user to select one item from the list. * QListWidget is a list of items that can be scrolled vertically. * QTableWidget is a table of items that can be scrolled vertically and horizontally. * QTreeView is a hierarchical list of items that can be scrolled vertically. **Practice:** * Try creating a QComboBox with a list of countries and connect its currentTextChanged signal to a slot that updates a label with the selected country. * Try creating a QListWidget with a list of items and connect its itemSelectionChanged signal to a slot that updates a label with the selected item. * Try creating a QTableWidget with a table of data and connect its cellChanged signal to a slot that updates a label with the changed cell. * Try creating a QTreeView with a file system model and connect its selectionChanged signal to a slot that updates a label with the selected file. **What's Next?** In the next topic, we will cover implementing validation in forms with QLabel and QLineEdit. We will explore how to validate user input and provide feedback to the user. **External Links:** * [PyQt6 Documentation](https://www.riverbankcomputing.com/static/Docs/PyQt6/) * [Qt Documentation](https://doc.qt.io/) **Comments and Help:** If you have any questions or need help with this topic, please leave a comment below.