Flutter / Dart using Scoped Model with descendants and Navigator - dart

Question

I've been struggling with this one since yesterday - I'm creating new ScopedModel obj in tab controller (ScreenTabs), and then passing it to multiple tabs in BottomNavigationBar (1st level descendants, for example: ScreenBook) by wrapping each tab as ScopedModelDescendant. So far so good - everything's working as expected.
The problem arises, when in one of my tabs, I'd like to navigate to it's child (2nd level descendant, for example: ScreenBookDetails) and use ScopedModel there. I've already tried using ScopedModelDescendant and ScopedModel.of(context) with no luck - getting Error: Could not find the correct ScopedModel everytime.
My code (skipped some for brevity):
TabController
...
class ScreenTabsState extends State<ScreenTabs> {
ModelTabs modelTabs = ModelTabs(); //new Model object
var screens = [new ScreenHome(),new ScreenBook(),];
#override
Widget build(BuildContext context) {
return ScopedModel<ModelTabs>(
model: modelTabs,
child: Scaffold(...)
body: Builder (builder: (context) => Container(child:
screens.elementAt(selectedIndex),)),
bottomNavigationBar: BottomNavigationBar(
currentIndex: selectedIndex,
items: [...],
onTap: onTabTapped,
),)...}
ScreenBook (1st ddescendant - ScpodedModel works as expected)
...
class ScreenBookState extends State<ScreenBook> {
#override
Widget build(BuildContext context) {
return new Scaffold(
body: ScopedModelDescendant<ModelTabs>(builder: (context, child, model) {
print(TAG + "model status:" + model.status.toString());
return model.status == Status.LOADING ? MyCircularProgressIndicator() :
Builder (builder: (context) =>
Card(...
child: InkWell(
onTap: (){
Navigator.of(context).pushNamed("/ScreenBookDetails");},))}}
ScreenBookDetails (1st ddescendant - error)
...
class ScreenBookDetailsState extends State<ScreenBookDetails>{
#override
Widget build(BuildContext context) {
return Scaffold(
body: ScopedModelDescendant<ModelTabs>(builder: (context, child, model) {
print(TAG + "scoped model status: " + model.status.toString()); //Error: Could not find the correct ScopedModel.
return model.status == Status.LOADING ? MyCircularProgressIndicator() : Builder(builder: (context) => Column(...)
...
can somebody point me the right way to fix thiis problem please? I'm new to Dart and Flutter, so there might be something that I did not understood clearly as I'm facing similar problem when creating ScopedModel obj in ScreenSplashScreen then navigating to ScreenLogIn and trying to use it there.
Thank you! :)

Answer 1

Finally found out how to handle ScopedModel including Navigator with help from ScopedModel's Github support - the key was to create a ScopeModel instance outside of build(BuildContext), then pass the instance through the constructor of next screen, like:
class HomePage extends StatelessWidget {
SampleScopedModel model = SampleScopedModel();
#override
Widget build(BuildContext context) {
return ScopedModel<SampleScopedModel>(
model: model,
child: Scaffold(
body: Container(),
floatingActionButton: FloatingActionButton(onPressed: () {
Navigator.push(context,
MaterialPageRoute(builder: (context) => NextPage(model))
);
}),
),
);
}
}
class NextPage extends StatelessWidget {
final SampleScopedModel model;
NextPage(this.model);
#override
Widget build(BuildContext context) {
return ScopedModel<SampleScopedModel>(
model: model,
child: Scaffold(
body: ScopedModelDescendant<SampleScopedModel>(
builder: (context, child, model) {
return Text(model.payload.toString());
})
),
);
}
}