Verify if list is empty on Flutter

Question

I have an app which shows data that comes from a API, but I'm having a problem, when the api isnt loaded yet the app is showing a error (because the list is empty and there is no data to show).

RangeError (index): Invalid value: Valid value range is empty: 0

Here is how i initiate the List at the top of the class:

List produtosList1 = <ProdutoOs>[];

Here is how i show the data:

  child: Text(
                           
            produtosList1[index].data,
            style: TextStyle(fontWeight: FontWeight.bold),
                          ),

Is there a way to change the "produtosList1[index].data" to a specific string when the List is empty?

malik kurosaki · Accepted Answer · 2021-02-03 12:21:52Z

1

child: Text(                  
 produtosList1.isEmpty()?"data is empty":produtosList1[index].data,
 style: TextStyle(fontWeight: FontWeight.bold),
),

answered Feb 3, 2021 at 12:21

malik kurosaki

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1 Comment

abrev Over a year ago

It worked, its the way i thought but i couldnt do, thanks!

Dharman · Accepted Answer · 2021-02-03 12:41:00Z

1

You can solve this problem using FutureBuilder(). The step by step procedure would be:

You should write the entire code of fetching data from API into a future method.
pass that future method as an argument in futurebuilder widget.
By using snapshot.hasData condition, check whether information is loaded or not.
If it's loaded, display it in list.
If not, show CircularProgressIndicator(),

edited Feb 3, 2021 at 12:41

Dharman♦

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answered Feb 3, 2021 at 12:35

Juzer Taher Totanawala

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