CODEWITHSUNDEEP
flutterdartfor-loopwidgetspread
Sparksteam
Sparksteam

Reputation: 1

Flutter/Dart : For Loop Inside a Widget

Can someone please explain how the for loop in this snippit works with the spread operator? It seems the spread should be operating on a single item collection, the Column. But I had to use the spread operator when I added the Text element in the Column's children. How does the flow work between the for loop, spread, Column, and it's children when building this widget? Thanks! Oh, and what's the reason why Flutter doesn't allow curly brackets for the body of a for loop inside the logic for building a widget? I assume there's a syntactical reason.

    return ListView(
      children: [
        Padding(
          padding: const EdgeInsets.all(20),
          child: Text('You have ${appState.favorites.length} favorites.'),
        ),

        for (var pair in appState.favorites)... [
          Column(
            children: [
              Text(pair.asLowerCase),
              ListTile(
                leading: Icon(Icons.favorite),
                title: Text(pair.asLowerCase),
              ),
            ]
          )
        ],
      ],
    );

I tried to logically compile the code in my head.

Upvotes: 0

Views: 491

Answers (1)

HasanToufiqAhamed
HasanToufiqAhamed

Reputation: 971

  List list1 = [];
  List list2 = [3, 4, 5];

  spread() {
    list1 = [1, for(var val in list2) ...[val]];
    //[1, ...[3]]
    //[1, ...[4]]
    //[1, ...[5]]
  }

this fist intem in this children on your example is Pading() and on my example is 1

using spread operator you can add full of the list2 with list1. on you example index 2 created depends on length of appState.favorites. on my example its [3, 4, 5]

just compare the your code with my example i think got proper explanation

Upvotes: 0

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