Flutter : Update all items in a ListView - flutter

Question

I'm trying to create a simpler contextual action bar(CAB) https://pub.dev/packages/contextualactionbar
What I want to do is to update all the items in a ListView in Flutter.
For example, I want to display a trailing checkbox for each ListTile when I long press on an item. The item can be a stateful widget.
Here is a gif of what I want to do:
I tried to use a GlobalKey example from https://stackoverflow.com/a/57310380/5712419
Using a GlobalKey, only the visible items would update.
Update 28/04/2021: I answered this question with something that worked for me: the Provider package. I think it is cleaner than using a GlobalKey.

Answer 1

It's possible to select all items in a ListView by using Provider. https://pub.dev/packages/provider
These are the steps I took.
Step 1: Create a class that extends ChangeNotifier for a single item
class SelectableItemState extends ChangeNotifier {
bool _selectable = false;
bool get selectable => _selectable;
set selectable(bool value) {
_selectable = value;
notifyListeners();
}
}
Step 2: Register the Change Notifier
return MultiProvider(
providers: [
ChangeNotifierProvider(create: (context) => SelectableItemState()),
], //...
Step 3: Create the Consumer, and update the state from the gesture detector
return Consumer<SelectableItemState>(builder: (context, state, child) {
return GestureDetector(){
onLongPress: () {
state.selectable = true;
},
child: Material( // use state.selectable in the item widget...
}
}
Step 4: Update the trailing of your item (if selectable, show checkbox, else, show an empty container)
trailing: (state.selectable)
? Checkbox(
value: // state.selectedItem,
onChanged: (value) {
setState(() {
// Here we can use something like
// state.setSelectedItem(item, value);
});
},
)
: Container(),