count total item

[vohoangtuit]

how to count total items in grouped_list ?

[bsolca]

Hello @vohoangtuit,

Here is my solution to add the number of items in each group.

final List<MapEntry<String, int>> _textList = [
  const MapEntry('Lorem', 0),
  const MapEntry('ipsum', 1),
  const MapEntry('dolor', 2),
  const MapEntry('sit', 3),
  const MapEntry('amet', 4),
  const MapEntry('consectetur', 5),
  const MapEntry('adipiscing', 6),
  const MapEntry('elit', 7),
  const MapEntry('sed', 8),
  const MapEntry('do', 9),
  const MapEntry('eiusmod', 10),
  const MapEntry('tempor', 11),
  const MapEntry('incididunt', 12),
  const MapEntry('ut', 14),
];
String groupBy(MapEntry<String, int> e) => e.value.isEven ? 'Even' : 'Odd';

Now you can use the groupHeaderBuilder and used the groupBy function to count the number of item in the group.

groupHeaderBuilder: (MapEntry<String, int> e) => Padding(
          padding: const EdgeInsets.all(8.0),
          child: Text(
            '${e.key} with ${_textList.where((test) {
              return groupBy(e) == groupBy(test);
            }).length} elements',
            textAlign: TextAlign.left,
            style: const TextStyle(
              fontSize: 20,
              fontWeight: FontWeight.bold,
              color: Colors.pink,
            ),
          ),
        ),

Result: