Flutter : How to retrieve index from map (List)

Question

I'm currently stuck on the flutter development where I need to retrieve the index from map to other parts of the Scaffold. Is it possible to retrieve the index value from the map below into other parts of Scaffold (Floating Action Button)?

  Iterable<int> get positiveIntegers sync* {
    int i = articleList.length - 1;
    while (true) yield i--;
  }

  @override
  Widget build(BuildContext context) {
    int getLength = articleList.length;
    var list = positiveIntegers.take(getLength).toList();

    return Scaffold(
      appBar: AppBar(
        title: new Text(
          'Popular',
          textAlign: TextAlign.center,
        ),
        textTheme: TextTheme(
            title: TextStyle(
                fontSize: 16,
                fontWeight: FontWeight.w700,
                color: Colors.black)),
        backgroundColor: Colors.white,
        centerTitle: true,
        elevation: 0.0,
      ),
      body: SwipeStack(
          children: list.map((index) {
              ...
          }
      ),
      floatingActionButton: Container(
        margin: EdgeInsets.only(top: 25, bottom: 25, left: 20),
        alignment: Alignment(0, 1),
        child: new Row(
          children: <Widget>[
            RawMaterialButton(
              onPressed: () {
                if (isOutOfCards == true) {
                  setState(() {
                    isOutOfCards = false;
                  });
                }
              },
              child: iconBuild(context),
              shape: new CircleBorder(),
              fillColor: Colors.red[700],
              splashColor: Colors.transparent,
              highlightColor: Colors.transparent,
              padding: const EdgeInsets.all(11),
            ),
            buttonTextBuild(context),
          ],
        ),
      ),
    );
  }

  Widget buttonTextBuild(BuildContext context) {
    if (isOutOfCards == false) {
      return Container(
          child: Text('$cardIndex/${articleList.length}',
              textAlign: TextAlign.left,
              style: TextStyle(
                  fontSize: 12.75,
                  fontWeight: FontWeight.w500,
                  letterSpacing: 1)));
    } else {
      return Container(
          child: Text('Start Again',
              textAlign: TextAlign.left,
              style: TextStyle(
                  fontSize: 12.75,
                  fontWeight: FontWeight.w500,
                  letterSpacing: 1)));
    }
  }

Like the code above I want to retrieve the 'index' from the list.map and pass it to the cardIndex inside buttonTextBuild.

Use List<int>.asMap(). Check the documentation here.

Abhilash Chandran
– Abhilash Chandran

2020-03-19 21:53:48 +00:00
Commented Mar 19, 2020 at 21:53 — Abhilash Chandran
– Abhilash Chandran, Commented Mar 19, 2020 at 21:53

Alex Radzishevsky · Accepted Answer · 2020-03-19 21:34:21Z

2

You can do this like that:

            children: [
              for(int index = 0; index < list.length; index++)
                Text(list[index])
            ]

Text widget is just example, you can use whatever widget you need or call function passing list[index] to get item

answered Mar 19, 2020 at 21:34

Alex Radzishevsky

3,7882 gold badges18 silver badges29 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Dray Tey Over a year ago

How do i pass this into an int? Cuz its a string

Alex Radzishevsky Over a year ago

list[index] is int, take it and pass to whatever you need

jamesdlin · Accepted Answer · 2020-03-19 21:38:46Z

1

You can use the enumerate function from the quiver package:

children: enumerate(list).map((indexedValue) {
  var index = indexedValue.index;
  var value = indexedValue.value;
  ...
}),

answered Mar 19, 2020 at 21:38

jamesdlin

91.2k14 gold badges185 silver badges224 bronze badges

Collectives™ on Stack Overflow

Flutter : How to retrieve index from map (List)

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related