testbed/Textualize__textual/docs/examples/guide/screens/modal01.py

from textual.app import App, ComposeResult
from textual.containers import Grid
from textual.screen import Screen
from textual.widgets import Static, Header, Footer, Button


class QuitScreen(Screen):
    def compose(self) -> ComposeResult:
        yield Grid(
            Static("Are you sure you want to quit?", id="question"),
            Button("Quit", variant="error", id="quit"),
            Button("Cancel", variant="primary", id="cancel"),
            id="dialog",
        )

    def on_button_pressed(self, event: Button.Pressed) -> None:
        if event.button.id == "quit":
            self.app.exit()
        else:
            self.app.pop_screen()


class ModalApp(App):
    CSS_PATH = "modal01.css"
    BINDINGS = [("q", "request_quit", "Quit")]

    def compose(self) -> ComposeResult:
        yield Header()
        yield Footer()

    def action_request_quit(self) -> None:
        self.push_screen(QuitScreen())


if __name__ == "__main__":
    app = ModalApp()
    app.run()