CODEWITHSUNDEEP
dartflutter
Yohan Malshika
Yohan Malshika

Reputation: 733

Process of List.generate Constructor in Dart

I am new to Flutter and Dart. I am trying to create long List View in Flutter. but I am stuck with this Constructor. Can anyone explain how this Constructor works?

List<String> = List<String>.generate(1000,(counter) => "Item $counter");

Upvotes: 6

Views: 37997

Answers (4)

Sanjay Bharwani
Sanjay Bharwani

Reputation: 4779

List.generate is very useful in terms of generating test data.

For e.g.

List<Student> getStudents({required int numOfStudents}) {
  return List.generate(
    numOfStudents,
    (index) => Student(
      id: '$index',
      firstName: 'FName$index',
      lastName: 'LName$index',
    ),
  );
}

It can be fully randomized by using

List.generate(random.nextInt(3), (index) => Student(
          id: '$index',
          firstName: 'FName$index',
          lastName: 'LName$index',
        ))

Upvotes: 2

Solen Dogan
Solen Dogan

Reputation: 149

List.generate can be very useful if you know the length and structure of the list you like to create. For example: You can create a List of maps too

Here generating a list with day e.g Mon, Tue,Wed,etc.. for the whole week see the 7 as the number of iterations.

      final myList = List.generate(7, (index) {
            final dateFormatted =DateTime.now().subtract(Duration(days:index));
                return {
                    'day':DateFormatted.E().format(dateF),
                    'date':dateFormatted,
             };
             });
        print(myList);

Upvotes: 2

Mohamed hassan kadri
Mohamed hassan kadri

Reputation: 1069

List<String> = List<String>.generate(1000,(counter) => "Item $counter");

this will generate 1000 item and you can manipulate each item threw your arrow function that takes counter as a parameter in that case counter will be ur index each time . the output will be :

"Item 0"
"Item 1"
"Item 2"
...
"Item 999"

Upvotes: 6

R&#233;mi Rousselet
R&#233;mi Rousselet

Reputation: 277137

The following:

List<String>.generate(1000,(counter) => "Item $counter");

will generate a List of 1000 items, where each item are in order:

"Item 0"
"Item 1"
"Item 2"
...
"Item 999"

Upvotes: 18

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