how I avoid FutureBuilder runs multiple times and duplicate the output List

Question

I have a Future function that returns a List and I had the problem that kept duplicating... I solved it by setting an initState() as described here: Flutter FutureBuilder gets constantly called flutter-futurebuilder-gets-constantly-called

Now I need the Future function to be executed when I press a button, to do this I have created a list to which I add the FutureBuilder when I press the button, but I have removed the initState().

So now the duplication problem is back...

Does anyone know how I can make FutureBuilder run only once when I press the button?

I cannot attach the code because it is too long and complicated, I hope I was clear enough and that someone can help me. Thanks :)

Answer 1

Hi maybe you can check my sample code below

class _MyHomePageState extends State<MyHomePage> {
  List<String> _myList = [];
  bool isLoading = false;

  setLoading()=>setState(()=>isLoading = !isLoading);
  
  Future<void> _myFunction()async{
    setLoading();
    await Future.delayed(const Duration(seconds:1));
    _myList.add("Some Text");
    setLoading();
  }

  @override
  initState(){
    _myFunction();
    super.initState();
  }
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          children: [
            const Text('Your List:'),
            ..._myList.map((e)=> Text(e)),
            if(isLoading) const CircularProgressIndicator()
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed:()=> _myFunction(),
        child: const Icon(Icons.add),
      ),
    );
  }
}