View.can_pop and View.on_confirm_pop (#5284)

* View.can_pop and View.on_confirm_pop

* Dismissible and View: added 5 minutes timeout for confirm callbacks

Author: FeodorFitsner

.gitignore

@@ -25,4 +25,5 @@
 .DS_Store
 *.bkp
 .python-version
-vendor/
+vendor/
+/client/android/app/.cxx

client/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme

@@ -48,6 +48,7 @@
       ignoresPersistentStateOnLaunch = "NO"
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
+      enableGPUValidationMode = "1"
       allowLocationSimulation = "YES">
       <BuildableProductRunnable
          runnableDebuggingMode = "0">

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

@@ -56,7 +56,8 @@ class _DismissibleControlState extends State<DismissibleControl> {
         parseDismissThresholds(widget.control, "dismissThresholds");
 
     DismissDirection direction = parseDismissDirection(
-        widget.control.attrString("dismissDirection"), DismissDirection.horizontal)!;
+        widget.control.attrString("dismissDirection"),
+        DismissDirection.horizontal)!;
 
     widget.backend.subscribeMethods(widget.control.id,
         (methodName, args) async {
@@ -118,7 +119,10 @@ class _DismissibleControlState extends State<DismissibleControl> {
                     widget.control.state["confirm_dismiss"] = completer;
                     widget.backend.triggerControlEvent(
                         widget.control.id, "confirm_dismiss", direction.name);
-                    return completer.future;
+                    return completer.future.timeout(
+                      const Duration(minutes: 5),
+                      onTimeout: () => false,
+                    );
                   }
                 : null,
             movementDuration: Duration(

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

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:convert';
 
 import 'package:collection/collection.dart';
@@ -768,6 +769,7 @@ class _PageControlState extends State<PageControl> with FletStoreMixin {
                 widgetsDesign: _widgetsDesign,
                 brightness: _brightness,
                 themeMode: _themeMode,
+                isRootView: view.id == routesView.views.first.id,
               );
 
               //debugPrint("ROUTES: $_prevViewRoutes $viewRoutes");
@@ -792,10 +794,11 @@ class _PageControlState extends State<PageControl> with FletStoreMixin {
           Widget nextChild = Navigator(
               key: navigatorKey,
               pages: pages,
-              onPopPage: (route, dynamic result) {
-                widget.backend.triggerControlEvent("page", "view_pop",
-                    ((route.settings as Page).key as ValueKey).value);
-                return false;
+              onDidRemovePage: (page) {
+                if (page.key != null) {
+                  widget.backend.triggerControlEvent(
+                      "page", "view_pop", (page.key as ValueKey).value);
+                }
               });
 
           // wrap navigator into non-visual offstage controls
@@ -821,9 +824,10 @@ class ViewControl extends StatefulWidget {
   final PageDesign widgetsDesign;
   final Brightness? brightness;
   final ThemeMode? themeMode;
+  final bool isRootView;
 
-  const ViewControl(
-      {super.key,
+  ViewControl(
+      {Key? key,
       required this.parent,
       required this.viewId,
       required this.overlayWidgets,
@@ -832,14 +836,17 @@ class ViewControl extends StatefulWidget {
       required this.parentAdaptive,
       required this.widgetsDesign,
       required this.brightness,
-      required this.themeMode});
+      required this.themeMode,
+      required this.isRootView})
+      : super(key: ValueKey("control_$viewId"));
 
   @override
   State<ViewControl> createState() => _ViewControlState();
 }
 
 class _ViewControlState extends State<ViewControl> with FletStoreMixin {
   final scaffoldKey = GlobalKey<ScaffoldState>();
+  Completer<bool>? _popCompleter;
 
   @override
   Widget build(BuildContext context) {
@@ -875,6 +882,16 @@ class _ViewControlState extends State<ViewControl> with FletStoreMixin {
               CrossAxisAlignment.start)!;
           final fabLocation = parseFloatingActionButtonLocation(
               control, "floatingActionButtonLocation");
+          final canPop = control.attrBool("canPop", true)!;
+
+          widget.backend.subscribeMethods(control.id, (methodName, args) async {
+            debugPrint("View.onMethod(${control.id})");
+            if (methodName == "confirm_pop") {
+              _popCompleter?.complete(bool.tryParse(args["shouldPop"] ?? ""));
+              widget.backend.unsubscribeMethods(control.id);
+            }
+            return null;
+          });
 
           Control? appBar;
           Control? cupertinoAppBar;
@@ -907,7 +924,8 @@ class _ViewControlState extends State<ViewControl> with FletStoreMixin {
                 ctrl.name == "drawer_start") {
               drawer = ctrl;
               continue;
-            } else if (ctrl.type == "navigationdrawer" && ctrl.name == "drawer_end") {
+            } else if (ctrl.type == "navigationdrawer" &&
+                ctrl.name == "drawer_end") {
               endDrawer = ctrl;
               continue;
             }
@@ -1153,13 +1171,41 @@ class _ViewControlState extends State<ViewControl> with FletStoreMixin {
                 child: scaffold,
               );
             }
-            var result = Directionality(
+            Widget result = Directionality(
                 textDirection: textDirection,
                 child: widget.loadingPage != null
                     ? Stack(
                         children: [scaffold, widget.loadingPage!],
                       )
                     : scaffold);
+
+            result = PopScope(
+                canPop: canPop,
+                onPopInvokedWithResult: (didPop, result) {
+                  if (didPop || !control.attrBool("onConfirmPop", false)!) {
+                    return;
+                  }
+                  debugPrint("Page.onPopInvokedWithResult()");
+                  _popCompleter = Completer<bool>();
+                  widget.backend
+                      .triggerControlEvent(widget.viewId, "confirm_pop");
+                  _popCompleter!.future
+                      .timeout(
+                    const Duration(minutes: 5),
+                    onTimeout: () => false,
+                  )
+                      .then((shouldPop) {
+                    if (context.mounted && shouldPop) {
+                      if (widget.isRootView) {
+                        SystemNavigator.pop();
+                      } else {
+                        Navigator.pop(context);
+                      }
+                    }
+                  });
+                },
+                child: result);
+
             return withPageArgs((context, pageArgs) {
               var backgroundDecoration = parseBoxDecoration(
                   Theme.of(context), control, "decoration", pageArgs);

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

@@ -15,6 +15,16 @@ bool isMobilePlatform() {
           defaultTargetPlatform == TargetPlatform.android);
 }
 
+/// Checks if the current platform is iOS
+bool isiOSPlatform() {
+  return !kIsWeb && defaultTargetPlatform == TargetPlatform.iOS;
+}
+
+/// Checks if the current platform is Android
+bool isAndroidPlatform() {
+  return !kIsWeb && defaultTargetPlatform == TargetPlatform.android;
+}
+
 /// Checks if the current platform is Windows desktop.
 bool isWindowsDesktop() {
   return !kIsWeb && (defaultTargetPlatform == TargetPlatform.windows);

sdk/python/packages/flet/src/flet/core/view.py

@@ -18,6 +18,7 @@
     FloatingActionButtonLocation,
     MainAxisAlignment,
     OffsetValue,
+    OptionalControlEventCallable,
     OptionalEventCallable,
     PaddingValue,
     ScrollMode,
@@ -55,6 +56,8 @@ def __init__(
         bgcolor: Optional[ColorValue] = None,
         decoration: Optional[BoxDecoration] = None,
         foreground_decoration: Optional[BoxDecoration] = None,
+        can_pop: Optional[bool] = None,
+        on_confirm_pop: OptionalControlEventCallable = None,
         #
         # ScrollableControl
         #
@@ -99,6 +102,8 @@ def __init__(
         self.fullscreen_dialog = fullscreen_dialog
         self.decoration = decoration
         self.foreground_decoration = foreground_decoration
+        self.can_pop = can_pop
+        self.on_confirm_pop = on_confirm_pop
 
     def _get_control_name(self):
         return "view"
@@ -134,6 +139,9 @@ def _get_children(self):
             children.append(self.__end_drawer)
         return children + self.__controls
 
+    def confirm_pop(self, shouldPop: bool):
+        self.invoke_method("confirm_pop", {"shouldPop": str(shouldPop).lower()})
+
     # route
     @property
     def route(self):
@@ -303,6 +311,25 @@ def decoration(self) -> Optional[BoxDecoration]:
     def decoration(self, value: Optional[BoxDecoration]):
         self.__decoration = value
 
+    # can_pop
+    @property
+    def can_pop(self) -> Optional[bool]:
+        return self._get_attr("canPop", data_type="bool")
+
+    @can_pop.setter
+    def can_pop(self, value: Optional[bool]):
+        self._set_attr("canPop", value)
+
+    # on_confirm_pop
+    @property
+    def on_confirm_pop(self):
+        return self._get_event_handler("confirm_pop")
+
+    @on_confirm_pop.setter
+    def on_confirm_pop(self, handler: OptionalControlEventCallable):
+        self._add_event_handler("confirm_pop", handler)
+        self._set_attr("onConfirmPop", True if handler is not None else None)
+
     # Magic methods
     def __contains__(self, item: Control) -> bool:
         return item in self.__controls