CODEWITHSUNDEEP
dartfluttergoogle-cloud-firestore
Cody Harness
Cody Harness

Reputation: 1147

How to sort list from FireStore

In my documents on FireStore, each one has a list of strings. When I'm displaying the document in app, I would like to sort them alphabetically. What I'm trying doesn't work.

var words = document['list'].cast<String>();
words.sort(); // Outputs 'null'

On inspection in the debugger, when I'm casting the list the object is of type CastList, but I can't find any info on this, and trying to create an object with that declared type tells me that it is an undefined class. So then I tried to specify the class that I'd like it to be:

List<String> words = document['list'].cast<String>();

But it still outputs null when I try to sort.

My collections look like this Collection example

I'm getting all of the documents inside of lists and displaying each of them in a listView.

StreamBuilder(
  stream: Firestore.instance.collection('lists').orderBy('releases').snapshots,
  builder: (context, snapshot) {
    if (!snapshot.hasData)
      return const Center(child: Text('Loading...'));

      return ListView.builder(
        itemCount: snapshot.data.documents.length,
        itemBuilder: (context, index) =>
            _buildRow(context, snapshot.data.documents[index], index),
      );
    },
)

  Widget _buildRow(BuildContext context, DocumentSnapshot document, int index) {
    var words = document['list'].cast<String>();
    var wordsString = words.toString();
    wordsString = wordsString.substring(1, wordsString.length - 1);

    return CheckboxListTile(
      title: Text(
        document['name'],
        style: _largerTextStyle,
      ),
      subtitle: Text(
        wordsString,
        style: _textStyle,
      ),
      value: _selectedIndices.contains(index),
      onChanged: (bool value) {
        setState(() {
          if (value) _selectedIndices.add(index);
          else _selectedIndices.remove(index);
        });
      },
    );
  }

Upvotes: 1

Views: 2282

Answers (1)

diegoveloper
diegoveloper

Reputation: 103561

It should work , don't need to call cast.

Edit: I think you forgot to extract the data.

List words = document.data['list'];
words.sort();

Upvotes: 1

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