complex_custome_semantics.dart

       ListView.builder(
        itemCount: 5,
        addSemanticIndexes: false,
        semanticChildCount: 3,
        itemBuilder: (context, position) {
          return MergeSemantics(
              child: Semantics(
                label: 'Container with 200 width 200 height and red background',
                enabled: position == 1 ? true : false,
                selected: position == 0 ? true : false,
                onTap: () {
                  Scaffold.of(context).showSnackBar(
                      SnackBar(content: Text('Item $position Clicked!')));
                },
                onScrollDown: () {
                  print('Scroll down happened');
                },
                child: Container(
                  margin: EdgeInsets.all(16),
                  color: Colors.red,
                  height: 200,
                  width: 200,
                  child: Column(
                    children: <Widget>[
                      Text('First inside text of item $position'),
                      BlockSemantics(
                          child: Text('Second inside text of item $position')),
                      ExcludeSemantics(
                          child: Text('Third inside text of item $position')),
                      Text('Fourth inside text of item $position')
                    ],
                  ),
                ),
              ),
          );