Can I use RefreshIndicator in Stateless flutter widget?

Question

I'm fetching some json data from the internet and displaying in a listview builder inside a stateless widget

Now I want to refresh the data using RefreshIndicator. Do I need a stateful widget for this or can I manage to do this with a stateless widget?

My understanding:

If I don't need to refresh, I load the data from internet only on the app start up, So Stateless widget is enough

If I need to refresh, it involves user input, but I don't need to manage a state, I just need to re-run the build method (Which I plan to do by Navigating to the same page, in the onRefresh parameter of RefreshIndicator)

So do I need a stateful widget?

score 1 · Answer 1 · answered Apr 16 '20 at 15:41

1

You must change the StatelessWidget to a StatefullWidget and use the function setState (){} to

answered Apr 16 '20 at 15:41

Pedro De la Cruz

11
1

Yes, I am using a statefulWidget with setState as of right now. But the fact that I don't actually need a state (Cause I'm not storing anything, Just loading things from internet) and am still using a StatefulWidget bothers me. Cause I heard it's a best practise to keep the number of StatefulWidgets to minimum. For my case, I want to be able to re-run the build method when user performs refresh without using a StatefulWidget – user730376 Apr 16 '20 at 15:54
I understand, but StatefullWidget is using when u need to rebuild the page to loading things from the internet again , not only to store data. – Gonzalo Gauto Apr 16 '20 at 16:22
Got it @GonzaG .Thanks – user730376 Apr 16 '20 at 16:28

score 0 · Answer 2 · answered Apr 16 '20 at 16:08

If you need a RefreshIndicator to get again the jsondata from the internet you must need a StateFullWidget because u need to rebuild the page with the newdata. There is no point in showing the indicator if you are not going to ask for new information.

score 0 · Answer 3 · answered Jan 13 '22 at 22:10

Because you want to reduce the StatefulWidget instances, you can delegate the task of fetching data to a parent stateful widget. You could pass a callback to perform the task of fetching data via the constructor of the StatelessWidget invoked whenever we want to refresh the data.

  class _ParentWidgetState extends State<ParentWidget>{
    ...
    Future<dynamic> _fetchData(){..}
    ...
    Widget build(BuildContext){
      return Container(
        ...
       ChildWidget(onRefresh:_fetchData)
       ...
      );
    }
  }

  class ChildWidget extends StatelessWidget{
    ChildWidget({Key? key,this.onRefresh}):super(key:key);
    final Future<dynamic> Function() onRefresh;
    ...
    @override
    Widget build(BuildContext context){
      return RefreshIndicator(
              onRefresh:onRefresh,
              child:..
      );
    ...
    }
  }

The point is to delegate the task of loading the data to a parent StatefulWidget's state so you could use other mechanisms like ChangeNotifier to make the parent widget's state call the API and render after calling setState future in its own state.

Can I use RefreshIndicator in Stateless flutter widget?

3 Answers3