mini_browser.py

import toga
from toga.constants import CENTER, COLUMN, ROW
from toga.validators import StartsWith


class Graze(toga.App):
    def startup(self):
        self.main_window = toga.MainWindow()

        self.webview = toga.WebView(on_webview_load=self.on_webview_loaded, flex=1)
        self.url_input = toga.TextInput(
            value="https://beeware.org/",
            on_confirm=self.load_page,
            flex=1,
            validators=[StartsWith("http://"), StartsWith("https://")],
        )

        box = toga.Box(
            children=[
                toga.Box(
                    children=[
                        self.url_input,
                        toga.Button(
                            "Go",
                            on_press=self.load_page,
                            width=50,
                            margin_left=5,
                        ),
                    ],
                    direction=ROW,
                    align_items=CENTER,
                    margin=5,
                ),
                self.webview,
            ],
            direction=COLUMN,
        )

        self.main_window.content = box
        self.webview.url = self.url_input.value

        # Show the main window
        self.main_window.show()

    async def load_page(self, widget):
        if self.url_input.is_valid:
            self.webview.url = self.url_input.value
        else:
            await self.main_window.dialog(
                toga.ErrorDialog(
                    "Invalid URL",
                    "Please enter a URL that starts with http:// or https:// and try again.",
                )
            )

    def on_webview_loaded(self, widget):
        self.url_input.value = self.webview.url


def main():
    return Graze("Graze", "org.beeware.toga.examples.tutorial")


if __name__ == "__main__":
    main().main_loop()