How to pass extra arguments to itemBuilder function of ListView.builder Widget in Flutter?

Question

I want to pass extra arguments to my itemBuilder function apart from content and index . How do I do this ?

body: new ListView.builder
  (
    itemCount: litems.length,
    itemBuilder: (BuildContext ctxt, int index) {
     return new Text(litems[index]);
    }
  )

I want something that does this :

int k = "HI";
body: new ListView.builder
  (
    itemCount: litems.length,
    itemBuilder: (BuildContext ctxt, int index, String k) {
     return new Text(litems[index] + k);
    }
  )

Günter Zöchbauer · Accepted Answer · 2018-09-23 16:23:44Z

11

There is no need for that.

You can access k from within the builder function body just fine without passing it as parameter.
You pass an inline function and that has access to the scope where it is defined.

If you don't have an inline builder function and you want/need to pass additional arguments you can use

String k = "HI";    
child: new ListView.builder(
  itemCount: litems.length,
  itemBuilder: (ctxt, Index) => _listItemBuilder(ctxt, Index, k)
)

...

Widget _listItemBuilder(BuildContext ctxt, int Index, String k) {
    return new Text(litems[Index] + k);
  }

edited Sep 23, 2018 at 16:23

answered Sep 23, 2018 at 15:53

Günter Zöchbauer

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2 Comments

Keshav Aditya R P Over a year ago

Is there a way to pass it explicitly as an argument though ?

Günter Zöchbauer Over a year ago

No and it wouldn't make sense. If you'd provide more context why you need this it would be easier to to make suggestions. I'll add one to my answer.

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