I'm still wrapping my head around state-management techniques in flutter and am a bit confused about when and why to use Provider.of<X> vs. Consumer<X>. I understand (I think) from the documentation that when choosing between these two you would use Provider.of when we want access to the data, but you don't need the UI to change. So the following (taken from the docs) gets access to the data and updates the UI on new events:
return HumongousWidget(
// ...
child: AnotherMonstrousWidget(// <- This widget will rebuild on new data events
// ...
child: Consumer<CartModel>(
builder: (context, cart, child) {
return Text('Total price: ${cart.totalPrice}');
},
),
),
);
Whereas, where we only need the data on don't want to rebuild with UI, we'd use Provider.of<X> with the listen parameter set to false, as below:
Provider.of<CartModel>(context, listen: false).add(item); \\Widget won't rebuild
However, listen isn't required and so the following will run too:
Provider.of<CartModel>(context).add(item); \\listener optional
So this brings me to a few questions:
- Is this the correct way to distinguish
Provider.of<X>andConsumer<X>. Former doesn't update UI, latter does? - If
listenisn't set tofalsewill the widget be rebuilt by default or not rebuilt? What iflistenis set totrue? - Why have
Provider.ofwith the option to rebuild the UI at all when we haveConsumer?
Best Answer
It doesn't matter. But to explain things rapidly:
Provider.ofis the only way to obtain and listen to an object.Consumer,Selector, and all the *ProxyProvider callsProvider.ofto work.Provider.ofvsConsumeris a matter of personal preference. But there's a few arguments for bothProvider.of
didChangeDependenciesConsumer