Flutter update Widgets automatically based on parameter changes

Question

I have a global variable and I want to refresh my Widgets automatically (without using setState each time) whenever its value changes.

Is that possible?

Answer 1

you should use provider for that link,

1. You start your root Build method in the app with:

@override
  Widget build(BuildContext context) {
    return MultiProvider(  // Multi means you can have more providers if you need
      providers: [
        ChangeNotifierProvider(builder: (context) => MyStateClass()),
      ],
      child: MaterialApp(....

2. Now you can place all the data you need to share in the MyStateClass() and place underlying Widgets inside:

 Consumer<MyStateClass>(builder: (context, state, child) {

      // your code here - return(SomeOtherWidget());
    })

3. or inside your Build methods:

  @override
  Widget build(BuildContext context) {
   MyStateClass state = Provider.of<MyStateClass>(context);
   // ... TODO  ... return (Widget)