I can't close ("quit") the app

[goehte]

I'm new to Tonga, I create this simple SQLite app.
But I can't close/quit the app. Any idea where is my bug?

import toga
from toga.style import Pack
from toga.style.pack import COLUMN, ROW
import sqlite3
from datetime import datetime
import sys

class BasicApp(toga.App):
    def startup(self):
        # Connect to SQLite database
        self.conn = sqlite3.connect("app1_sqlite.db")
        self.cursor = self.conn.cursor()
        self.cursor.execute('''
            CREATE TABLE IF NOT EXISTS entries (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                first_name TEXT NOT NULL,
                second_name TEXT NOT NULL,
                town TEXT NOT NULL,
                zip_code TEXT NOT NULL,
                street TEXT NOT NULL,
                street_no TEXT NOT NULL,
                birth_date TEXT NOT NULL
            )
        ''')
        self.conn.commit()

        # UI Elements
        first_name_input = toga.TextInput(placeholder="First Name", style=Pack(margin=5))
        second_name_input = toga.TextInput(placeholder="Second Name", style=Pack(margin=5))
        town_input = toga.TextInput(placeholder="Town", style=Pack(margin=5))
        zip_code_input = toga.TextInput(placeholder="ZIP Code", style=Pack(margin=5))
        street_input = toga.TextInput(placeholder="Street", style=Pack(margin=5))
        street_no_input = toga.TextInput(placeholder="Street No.", style=Pack(margin=5))
        birth_date_input = toga.TextInput(placeholder="Birth Date (YYYY-MM-DD)", style=Pack(margin=5))

        # Buttons
        add_button = toga.Button("Add Entry", on_press=self.add_entry, style=Pack(margin=5))
        self.edit_button = toga.Button("Edit Selected", on_press=self.edit_entry, style=Pack(margin=5), enabled=False)
        self.delete_button = toga.Button("Delete Selected", on_press=self.delete_entry, style=Pack(margin=5), enabled=False)

        # Add Quit button
        quit_button = toga.Button("Quit", on_press=self.quit_app, style=Pack(margin=5))

        # Table
        self.table = toga.Table(
            headings=["ID", "First Name", "Second Name", "Town", "ZIP Code", "Street", "Street No.", "Birth Date"],
            data=[],
            style=Pack(flex=1, margin=5),
            on_select=self.on_table_select
        )

        # Filter and sort UI
        self.search_input = toga.TextInput(placeholder="Search...", style=Pack(flex=1, margin=5))
        self.search_button = toga.Button("Filter", on_press=self.filter_data, style=Pack(margin=5))
        self.sort_by = toga.Selection(
            items=["First Name", "Second Name", "Town", "ZIP Code", "Street", "Street No.", "Birth Date"],
            style=Pack(margin=5, width=150)
        )
        self.sort_order = toga.Switch("Descending", style=Pack(margin=5))
        self.sort_button = toga.Button("Apply Sort", on_press=self.filter_data, style=Pack(margin=5))

        # Input layout
        input_box = toga.Box(
            children=[
                toga.Label("First Name:"), first_name_input,
                toga.Label("Second Name:"), second_name_input,
                toga.Label("Town:"), town_input,
                toga.Label("ZIP Code:"), zip_code_input,
                toga.Label("Street:"), street_input,
                toga.Label("Street No.:"), street_no_input,
                toga.Label("Birth Date (YYYY-MM-DD):"), birth_date_input,
                toga.Box(
                    children=[add_button, self.edit_button, self.delete_button, quit_button],
                    style=Pack(direction=ROW, margin=5)
                )
            ],
            style=Pack(direction=COLUMN, margin=5)
        )

        # Filter and sort layout
        filter_sort_box = toga.Box(
            children=[self.search_input, self.search_button, self.sort_by, self.sort_order, self.sort_button],
            style=Pack(direction=ROW, margin=5)
        )

        # Main layout
        main_box = toga.Box(
            children=[input_box, filter_sort_box, self.table],
            style=Pack(direction=COLUMN, margin=10)
        )

        # Store inputs
        self.inputs = {
            "first_name": first_name_input,
            "second_name": second_name_input,
            "town": town_input,
            "zip_code": zip_code_input,
            "street": street_input,
            "street_no": street_no_input,
            "birth_date": birth_date_input
        }

        # Window
        self.main_window = toga.MainWindow(title="Toga SQLite App")
        self.main_window.content = main_box
        self.main_window.show()

        # Load data into table
        self.load_data()

    def quit_app(self, widget):
        """Close the application."""
        self.on_exit()
        sys.exit(0)

    def on_table_select(self, widget):
        has_selection = self.table.selection is not None
        self.edit_button.enabled = has_selection
        self.delete_button.enabled = has_selection

        if has_selection:
            try:
                row = self.table.selection
                self.inputs["first_name"].value = row.first_name
                self.inputs["second_name"].value = row.second_name
                self.inputs["town"].value = row.town
                self.inputs["zip_code"].value = row.zip_code
                self.inputs["street"].value = row.street
                self.inputs["street_no"].value = row.street_no
                self.inputs["birth_date"].value = row.birth_date
            except Exception as e:
                print(f"Failed to populate fields: {e}")

    def load_data(self, filter_text=None):
        query = "SELECT * FROM entries"
        params = []
        if filter_text:
            query += """
                WHERE
                    first_name LIKE ? OR
                    second_name LIKE ? OR
                    town LIKE ? OR
                    zip_code LIKE ? OR
                    street LIKE ? OR
                    street_no LIKE ? OR
                    birth_date LIKE ?
            """
            wildcard = f"%{filter_text}%"
            params = [wildcard] * 7

        # Sorting
        sort_column_map = {
            "First Name": "first_name",
            "Second Name": "second_name",
            "Town": "town",
            "ZIP Code": "zip_code",
            "Street": "street",
            "Street No.": "street_no",
            "Birth Date": "birth_date"
        }

        if self.sort_by.value:
            sort_column = sort_column_map[self.sort_by.value]
            direction = "DESC" if self.sort_order.value else "ASC"
            query += f" ORDER BY {sort_column} {direction}"

        self.cursor.execute(query, params)
        self.table.data = self.cursor.fetchall()
        self.table.refresh()

    def filter_data(self, widget=None):
        search_term = self.search_input.value.strip()
        self.load_data(filter_text=search_term)

    def add_entry(self, widget):
        values = {key: input_field.value for key, input_field in self.inputs.items()}
        if not all(values.values()):
            self.main_window.error_dialog("Error", "All fields are required!")
            return

        # Validate birth date format
        try:
            datetime.strptime(values["birth_date"], "%Y-%m-%d")
        except ValueError:
            self.main_window.error_dialog("Error", "Birth Date must be in YYYY-MM-DD format!")
            return

        self.cursor.execute('''
            INSERT INTO entries (first_name, second_name, town, zip_code, street, street_no, birth_date)
            VALUES (?, ?, ?, ?, ?, ?, ?)
        ''', (
            values["first_name"], values["second_name"], values["town"], values["zip_code"],
            values["street"], values["street_no"], values["birth_date"]
        ))
        self.conn.commit()
        self.load_data()
        self.clear_inputs()

    def edit_entry(self, widget):
        row = self.table.selection
        if not row:
            self.main_window.error_dialog("Error", "Select a row to edit.")
            return

        values = {key: input_field.value for key, input_field in self.inputs.items()}
        if not all(values.values()):
            self.main_window.error_dialog("Error", "All fields are required!")
            return

        # Validate birth date format
        try:
            datetime.strptime(values["birth_date"], "%Y-%m-%d")
        except ValueError:
            self.main_window.error_dialog("Error", "Birth Date must be in YYYY-MM-DD format!")
            return

        try:
            self.cursor.execute('''
                UPDATE entries
                SET first_name=?, second_name=?, town=?, zip_code=?, street=?, street_no=?, birth_date=?
                WHERE id=?
            ''', (
                values["first_name"], values["second_name"], values["town"], values["zip_code"],
                values["street"], values["street_no"], values["birth_date"], row.id
            ))
            self.conn.commit()
            self.load_data()
            self.clear_inputs()
            self.edit_button.enabled = False
            self.delete_button.enabled = False
        except Exception as e:
            self.main_window.error_dialog("Error", f"Failed to update entry: {e}")

    def delete_entry(self, widget):
        row = self.table.selection
        if not row:
            self.main_window.error_dialog("Error", "Select a row to delete.")
            return

        self.cursor.execute("DELETE FROM entries WHERE id=?", (row.id,))
        self.conn.commit()
        self.load_data()
        self.clear_inputs()

    def clear_inputs(self):
        for widget in self.inputs.values():
            widget.value = ""

    def on_exit(self):
        """Clean up resources when the application exits."""
        self.conn.close()

def main():
    return BasicApp()

[freakboy3742]

You haven't provided much detail about the exact details of the behavior you're seeing, or the platform you're seeing it on; but my guess would be that your on_exit() method is the problem.

on_exit() has a return value - if you return False, the request to exit the app is rejected. Your on_exit() method doesn't have a return statement; so it will be defaulting to return None - which is a False-y value, preventing the app from exiting.

[goehte]

    def on_exit(self):
        self.conn.close()
        return True  # Allow the application to exit

Thanks a lot for highlighting this. It was the solution.