AppLifecycleState enum and typed event handler (#2808)

Author: FeodorFitsner

sdk/python/packages/flet-core/src/flet_core/__init__.py

@@ -171,6 +171,7 @@
 from flet_core.outlined_button import OutlinedButton
 from flet_core.padding import Padding
 from flet_core.page import (
+    AppLifecycleStateChangeEvent,
     KeyboardEvent,
     LoginEvent,
     Page,
@@ -249,6 +250,7 @@
 from flet_core.transform import Offset, Rotate, Scale
 from flet_core.transparent_pointer import TransparentPointer
 from flet_core.types import (
+    AppLifecycleState,
     BlendMode,
     BoxShape,
     Brightness,

sdk/python/packages/flet-core/src/flet_core/page.py

@@ -43,6 +43,7 @@
 from flet_core.snack_bar import SnackBar
 from flet_core.theme import Theme
 from flet_core.types import (
+    AppLifecycleState,
     Brightness,
     CrossAxisAlignment,
     FloatingActionButtonLocation,
@@ -155,7 +156,13 @@ def __init__(
             "platformBrightnessChange",
             self.__on_platform_brightness_change.get_handler(),
         )
-        self.__on_app_lifecycle_state_change = EventHandler()
+
+        def convert_app_lifecycle_state_change_event(e):
+            return AppLifecycleStateChangeEvent(e)
+
+        self.__on_app_lifecycle_state_change = EventHandler(
+            convert_app_lifecycle_state_change_event
+        )
         self._add_event_handler(
             "app_lifecycle_state_change",
             self.__on_app_lifecycle_state_change.get_handler(),
@@ -2086,3 +2093,10 @@ def __init__(self, padding, view_padding, view_insets) -> None:
 
     def __str__(self) -> str:
         return f"PageMediaData(padding={self.padding}, view_padding={self.view_padding}, view_insets={self.view_insets})"
+
+
+class AppLifecycleStateChangeEvent(ControlEvent):
+    def __init__(self, e: ControlEvent):
+        super().__init__(e.target, e.name, e.data, e.control, e.page)
+
+        self.state = AppLifecycleState(e.data)

sdk/python/packages/flet-core/src/flet_core/types.py

@@ -239,3 +239,13 @@ class FloatingActionButtonLocation(Enum):
     START_DOCKED = "startDocked"
     START_FLOAT = "startFloat"
     START_TOP = "startTop"
+
+
+class AppLifecycleState(Enum):
+    SHOW = "show"
+    RESUME = "resume"
+    HIDE = "hide"
+    INACTIVE = "inactive"
+    PAUSE = "pause"
+    DETACH = "detach"
+    RESTART = "restart"

sdk/python/packages/flet-runtime/src/flet_runtime/app.py

@@ -135,11 +135,13 @@ def on_app_startup(page_url):
         if view == AppView.WEB_BROWSER and url_prefix is None and not force_web_server:
             open_in_browser(page_url)
 
+    loop = asyncio.get_running_loop()
+
     terminate = asyncio.Event()
 
     def exit_gracefully(signum, frame):
         logger.debug("Gracefully terminating Flet app...")
-        asyncio.get_event_loop().call_soon_threadsafe(terminate.set)
+        loop.call_soon_threadsafe(terminate.set)
 
     signal.signal(signal.SIGINT, exit_gracefully)
     signal.signal(signal.SIGTERM, exit_gracefully)