Flutter - load data async inside initState

Question

Just after new page is created, I need to load webservice data (while loading is in progress, busy inducator should be displayed), then when loading done, show data.

My approach is load data inside initState override, this way:

void initState() {
    
      setState(() => _isLoading = true);
      fetchData().then((value) {

       // Do something with data
       widget.value = value;

        setState(() => _isLoading = false);
      });
    }

    super.initState();
  }

Then, build method will display either loading indicator, or loaded data depend from _isLoading value.

For now, it works but I don't feel it's good way, especially afaik, setState call should be avoided inside initState.

Can you provide any tips how to do the same better, without complicating code too much? Or, my approach is acceptable in this case?

darshan · Accepted Answer · 2021-05-29 10:54:10Z

2

Why don't you use FutureBuilder to build the Widgets?
You'll then be able to deal with the 'loading' state too.

Example:

return FutureBuilder(
    future: yourAsyncCall,
    builder: (context, snapshot) {
      if (!snapshot.hasData) return MaybeProgressBar();
      else return TheWidgetYouMade();
    }
});

edited May 29, 2021 at 10:54

darshan

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answered May 29, 2021 at 9:12

CrimsonFoot

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2 Comments

Gpack Over a year ago

FutureBuilder is correct but make sure that yourAsyncCall is made in the initState method, store the result in the state and pass it to the FutureBuilder. Read the docs carefully

user1209216 Over a year ago

Good solution, I forgot about FutureBuilder

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