Flutter Bloc Design - Inform pages about changes - flutter

Question

is there a best practice for this? (Im using this Todo example since its easier to explain my problem here)
TodoOverviewPage (Shows all todos)
TodoAddPage (Page to add todos)
Each page has an own Bloc.
Steps:
From the TodoOverviewPage I navigate wuth pushNamed to TodoAddPage.
In TodoAddPage I add several Todos.
Using the Navigation Back Button to go back to TodoOverviewPage
Question: How should I inform TodoOverviewPage that there are new Todos?
My approaches which Im not sure if this is the right way.
Solutions:
Overwriting the Back Button in TodoAddPage. To add a "refresh=true" property.
Adding the Bloc from TodoOverviewPage to TodoAddPage. And setting the State to something that the TodoOverviewPage will reload todos after building.
Thank you for reading.
EDIT1:
Added my temporary solution till I find something which satisfies me more.

Answer 1

You can achieve by different way
InheritedWidget
ValueCallback in TodoAddPage
For Example:
class Item {
String reference;
Item(this.reference);
}
class _MyInherited extends InheritedWidget {
_MyInherited({
Key key,
#required Widget child,
#required this.data,
}) : super(key: key, child: child);
final MyInheritedWidgetState data;
#override
bool updateShouldNotify(_MyInherited oldWidget) {
return true;
}
}
class MyInheritedWidget extends StatefulWidget {
MyInheritedWidget({
Key key,
this.child,
}): super(key: key);
final Widget child;
#override
MyInheritedWidgetState createState() => new MyInheritedWidgetState();
static MyInheritedWidgetState of(BuildContext context){
return (context.inheritFromWidgetOfExactType(_MyInherited) as _MyInherited).data;
}
}
class MyInheritedWidgetState extends State<MyInheritedWidget>{
/// List of Items
List<Item> _items = <Item>[];
/// Getter (number of items)
int get itemsCount => _items.length;
/// Helper method to add an Item
void addItem(String reference){
setState((){
_items.add(new Item(reference));
});
}
#override
Widget build(BuildContext context){
return new _MyInherited(
data: this,
child: widget.child,
);
}
}
class MyTree extends StatefulWidget {
#override
_MyTreeState createState() => new _MyTreeState();
}
class _MyTreeState extends State<MyTree> {
#override
Widget build(BuildContext context) {
return new MyInheritedWidget(
child: new Scaffold(
appBar: new AppBar(
title: new Text('Title'),
),
body: new Column(
children: <Widget>[
new WidgetA(),
new Container(
child: new Row(
children: <Widget>[
new Icon(Icons.shopping_cart),
new WidgetB(),
new WidgetC(),
],
),
),
],
),
),
);
}
}
class WidgetA extends StatelessWidget {
#override
Widget build(BuildContext context) {
final MyInheritedWidgetState state = MyInheritedWidget.of(context);
return new Container(
child: new RaisedButton(
child: new Text('Add Item'),
onPressed: () {
state.addItem('new item');
},
),
);
}
}
class WidgetB extends StatelessWidget {
#override
Widget build(BuildContext context) {
final MyInheritedWidgetState state = MyInheritedWidget.of(context);
return new Text('${state.itemsCount}');
}
}
class WidgetC extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new Text('I am Widget C');
}
}

Answer 2

Temporary solution:
Each (root) Page which has a Bloc now always reloads when build.
The Bloc takes care for caching.
Widget build(BuildContext context) {
final PageBloc pBloc = BlocProvider.of<PageBloc >(context);
bool isNewBuild = true;
return Scaffold(
...
body: BlocBuilder<PageBlocEvent, PageBlocState>(
if (isNewBuild) {
pBloc.dispatch(PageBlocEvent(PageBlocEventType.GETALL));
isNewBuild = false;
return CircularProgressIndicator();
} else {
// Draw data
...
...
}