feat: Fullscreen support on Mobile & Web

client/lib/main.dart

@@ -87,8 +87,7 @@ void main([List<String>? args]) async {
         assetsDir = args[2];
         debugPrint("Args contain a path assets directory: $assetsDir}");
       }
-    } else if (!kDebugMode &&
-        (Platform.isWindows || Platform.isMacOS || Platform.isLinux)) {
+    } else if (!kDebugMode && isDesktopPlatform()) {
       throw Exception(
           'In desktop mode Flet app URL must be provided as a first argument.');
     }

packages/flet/lib/src/controls/page.dart

@@ -32,6 +32,8 @@ import '../utils/session_store_web.dart'
 import '../utils/theme.dart';
 import '../utils/time.dart';
 import '../utils/user_fonts.dart';
+import '../utils/web_interface.dart'
+    if (dart.library.io) "../utils/io_interface.dart";
 import '../widgets/animated_transition_page.dart';
 import '../widgets/loading_page.dart';
 import '../widgets/page_context.dart';
@@ -197,6 +199,22 @@ class _PageControlState extends State<PageControl> with WidgetsBindingObserver {
           await SystemChrome.setPreferredOrientations(orientations);
         }
         break;
+      case "set_fullscreen":
+        final value = parseBool(args["value"]);
+        if (value != null) {
+          if (isDesktopPlatform() || isWebPlatform()) {
+            await setWindowFullScreen(value);
+          } else if (isMobilePlatform()) {
+            if (value) {
+              await SystemChrome.setEnabledSystemUIMode(
+                  SystemUiMode.immersiveSticky);
+            } else {
+              await SystemChrome.setEnabledSystemUIMode(SystemUiMode.manual,
+                  overlays: SystemUiOverlay.values);
+            }
+          }
+        }
+        break;
 
       default:
         throw Exception("Unknown Page method: $name");

packages/flet/lib/src/utils/user_fonts_io.dart → packages/flet/lib/src/utils/io_interface.dart

@@ -1,8 +1,14 @@
-import 'dart:typed_data';
 import 'dart:io';
+import 'dart:typed_data';
+
+import 'desktop.dart' as desktop show setWindowFullScreen;
 
 Future<ByteData> fetchFontFromFile(String path) async {
   File file = File(path);
   Uint8List bytes = await file.readAsBytes();
   return ByteData.view(bytes.buffer);
 }
+
+Future setWindowFullScreen(bool fullScreen) async {
+  await desktop.setWindowFullScreen(fullScreen);
+}

packages/flet/lib/src/utils/user_fonts.dart

@@ -3,7 +3,7 @@ import 'package:flutter/services.dart';
 import 'package:http/http.dart' as http;
 
 import '../models/control.dart';
-import 'user_fonts_web.dart' if (dart.library.io) "user_fonts_io.dart";
+import 'web_interface.dart' if (dart.library.io) "io_interface.dart";
 
 class UserFonts {
   static Map<String, FontLoader> fontLoaders = {};

packages/flet/lib/src/utils/web_interface.dart

@@ -0,0 +1,15 @@
+import 'dart:typed_data';
+
+import 'package:web/web.dart' as web show window;
+
+Future<ByteData> fetchFontFromFile(String path) async {
+  throw UnimplementedError();
+}
+
+Future setWindowFullScreen(bool fullScreen) async {
+  if (fullScreen) {
+    web.window.document.documentElement?.requestFullscreen();
+  } else {
+    web.window.document.exitFullscreen();
+  }
+}

sdk/python/examples/controls/page/fullscreen.py

@@ -0,0 +1,22 @@
+import flet as ft
+
+
+def main(page: ft.Page) -> None:
+    page.vertical_alignment = ft.MainAxisAlignment.CENTER
+    page.horizontal_alignment = ft.CrossAxisAlignment.CENTER
+
+    def handle_fullscreen_change(e: ft.Event[ft.Switch]):
+        page.full_screen = e.control.value
+
+    page.add(
+        ft.SafeArea(
+            ft.Switch(
+                value=page.full_screen,
+                label="Toggle Fullscreen",
+                on_change=handle_fullscreen_change,
+            ),
+        )
+    )
+
+
+ft.run(main)

sdk/python/packages/flet/docs/controls/page.md

@@ -29,6 +29,21 @@ Shows how to lock your app to specific device orientations
 --8<-- "{{ examples }}/app_exit_confirm_dialog.py"
 ```
 
+### Toggle Fullscreen
+
+This example demonstrates how to toggle fullscreen mode in a Flet application.
+
+/// admonition
+    type: note
+[`Page.full_screen`][flet.] is cross-platform (mobile, desktop and web), whereas
+[`Page.window.full_screen`][flet.Window.full_screen] is desktop only.
+///
+
+
+```python
+--8<-- "{{ examples }}/fullscreen.py"
+```
+
 ### Hidden app window on startup
 
 ```python

sdk/python/packages/flet/src/flet/controls/page.py

@@ -344,6 +344,28 @@ class Page(BasePage):
     Usage example [here](https://flet.dev/docs/cookbook/fonts#importing-fonts).
     """
 
+    @property
+    def full_screen(self) -> bool:
+        """
+        Requests fullscreen mode for the host window or browser.
+
+        Set to `True` to hide the host system chrome; set to `False` to restore it.
+        """
+        return getattr(
+            self,
+            "__full_screen",
+            self.page.window.full_screen if self.page.platform.is_desktop() else False,
+        )
+
+    @full_screen.setter
+    def full_screen(self, value: bool) -> None:
+        self.__full_screen = value
+        if self.page.platform.is_desktop() and not self.page.web:
+            self.page.window.full_screen = value
+        asyncio.create_task(
+            self._invoke_method("set_fullscreen", arguments={"value": value})
+        )
+
     on_platform_brightness_change: Optional[
         EventHandler[PlatformBrightnessChangeEvent]
     ] = None