Fix SnackBar (and other controls) exit animation

Author: FeodorFitsner

package/lib/src/controls/create_control.dart

@@ -73,7 +73,7 @@ import 'window_drag_area.dart';
 Widget createControl(Control? parent, String id, bool parentDisabled,
     {Widget? nextChild}) {
   //debugPrint("createControl(): $id");
-  return StoreConnector<AppState, ControlViewModel>(
+  return StoreConnector<AppState, ControlViewModel?>(
     key: ValueKey<String>(id),
     distinct: true,
     converter: (store) {
@@ -88,6 +88,10 @@ Widget createControl(Control? parent, String id, bool parentDisabled,
       return state.controls[id] == null;
     },
     builder: (context, controlView) {
+      if (controlView == null) {
+        return const SizedBox.shrink();
+      }
+
       //debugPrint("createControl builder(): $id");
       switch (controlView.control.type) {
         case "page":

package/lib/src/controls/page.dart

@@ -534,7 +534,7 @@ class _PageControlState extends State<PageControl> {
     return StoreConnector<AppState, ControlViewModel>(
         distinct: true,
         converter: (store) {
-          return ControlViewModel.fromStore(store, viewId);
+          return ControlViewModel.fromStore(store, viewId)!;
         },
         ignoreChange: (state) {
           return state.controls[viewId] == null;

package/lib/src/models/control_view_model.dart

@@ -13,14 +13,17 @@ class ControlViewModel extends Equatable {
   const ControlViewModel(
       {required this.control, required this.children, required this.dispatch});
 
-  static ControlViewModel fromStore(Store<AppState> store, String id) {
-    return ControlViewModel(
-        control: store.state.controls[id]!,
-        children: store.state.controls[id]!.childIds
-            .map((childId) => store.state.controls[childId])
-            .whereNotNull()
-            .toList(),
-        dispatch: store.dispatch);
+  static ControlViewModel? fromStore(Store<AppState> store, String id) {
+    var control = store.state.controls[id];
+    return control != null
+        ? ControlViewModel(
+            control: control,
+            children: control.childIds
+                .map((childId) => store.state.controls[childId])
+                .whereNotNull()
+                .toList(),
+            dispatch: store.dispatch)
+        : null;
   }
 
   @override

package/lib/src/models/controls_view_model.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart';
 import 'package:equatable/equatable.dart';
 import 'package:redux/redux.dart';
 
@@ -13,8 +14,10 @@ class ControlsViewModel extends Equatable {
   static ControlsViewModel fromStore(
       Store<AppState> store, Iterable<String> ids) {
     return ControlsViewModel(
-        controlViews:
-            ids.map((id) => ControlViewModel.fromStore(store, id)).toList(),
+        controlViews: ids
+            .map((id) => ControlViewModel.fromStore(store, id))
+            .whereNotNull()
+            .toList(),
         dispatch: store.dispatch);
   }