**Course Title:** PyQt6 Application Development **Section Title:** Advanced Widgets and Forms **Topic:** Creating a form with advanced widgets and custom validation **Lab Overview** In this lab, we will create a form that utilizes advanced widgets and custom validation techniques. The goal is to create a form that is functional, user-friendly, and validates user input in a robust way. We will use PyQt6 to create the form and implement custom validation rules to ensure data integrity. **Lab Objectives** By the end of this lab, you will be able to: * Create a form with advanced widgets such as QComboBox, QListWidget, QTableWidget, and QTreeView * Implement custom validation rules for user input * Use PyQt6 signals and slots to connect widgets and perform actions * Use a QValidator to validate user input **Lab Materials** * Python 3.7+ * PyQt6 * Qt Designer (optional) **Step 1: Create a New PyQt6 Project** Create a new PyQt6 project using your preferred IDE. Name the project "AdvancedForm". **Step 2: Design the Form** Using Qt Designer, create a new form (mainwindow.ui) and add the following widgets: * QComboBox * QListWidget * QTableWidget * QTreeView * QLineEdit * QPushButton Arrange the widgets in a way that makes sense for your application. Save the form. **Step 3: Implement Custom Validation** Create a new Python file called "validator.py" and add the following code: ```python import re def validate_email(email): pattern = r"^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$" if re.match(pattern, email): return True else: return False def validate_password(password): if len(password) < 8: return False else: return True ``` This code defines two custom validation functions for email and password. **Step 4: Connect Widgets and Perform Actions** In the main.py file, create a new class that inherits from QMainWindow. Connect the widgets to signals and slots: ```python import sys from PyQt6.QtWidgets import QApplication, QMainWindow, QComboBox, QListWidget, QTableWidget, QTreeView, QLineEdit, QPushButton from PyQt6.QtGui import QValidator from PyQt6.QtCore import Qt from validator import validate_email, validate_password class MainWindow(QMainWindow): def __init__(self): super().__init__() # Create a QValidator instance self.validator = QValidator() # Connect widgets to signals and slots self.combo_box.currentTextChanged.connect(self.combo_box_changed) self.list_widget.itemSelectionChanged.connect(self.list_widget_changed) self.table_widget.cellChanged.connect(self.table_widget_changed) self.tree_view.selectionChanged.connect(self.tree_view_changed) self.line_edit.textChanged.connect(self.line_edit_changed) self.push_button.clicked.connect(self.push_button_clicked) def combo_box_changed(self): print("Combo box selection changed") def list_widget_changed(self): print("List widget selection changed") def table_widget_changed(self): print("Table widget cell changed") def tree_view_changed(self): print("Tree view selection changed") def line_edit_changed(self, text): if not validate_email(text): self.line_edit.setStyleSheet("border: 1px solid red") def push_button_clicked(self): if not validate_password(self.line_edit.text()): print("Invalid password") else: print("Valid password") if __name__ == "__main__": app = QApplication(sys.argv) window = MainWindow() window.show() sys.exit(app.exec()) ``` This code connects the widgets to signals and slots and uses the custom validation functions to validate user input. **Step 5: Run the Application** Run the application by executing the main.py file. **Lab Conclusion** In this lab, we created a form with advanced widgets and custom validation rules. We used PyQt6 to create the form and implement custom validation rules to ensure data integrity. We connected widgets to signals and slots to perform actions and used a QValidator instance to validate user input. **External Resources:** * PyQt6 Documentation: [https://www.riverbankcomputing.com/static/Docs/PyQt6/](https://www.riverbankcomputing.com/static/Docs/PyQt6/) * Qt Designer: [https://www.qt.io/download-open-source](https://www.qt.io/download-open-source) **Ask for Help:** If you have any questions or need help with the lab, please leave a comment below or ask for assistance. **What's Next:** In the next lab, we will design dynamic UIs that adapt to window resizing. We will use PyQt6's layout management system to create responsive and adaptive UIs.