Update an icon of a feature when selected

[ludovicjamet]

I'm a bit lost with the poor documentation regarding the feature-state so I don't know if it's a bug or a wrong implementation.

I have this function that does set the feature-state

  Future<void> _changeSelectedMarker({ExtendedActivity? previousSelection, ExtendedActivity? newSelection}) async {
    if (previousSelection != null) {
      LoggingService.instance.debug('Deselecting marker with ID: ${previousSelection.activity.firebaseId}');
      map.setFeatureState(
        "activity-source",
        null,
        previousSelection.activity.firebaseId,
        jsonEncode({"selected": false}),
      );
    }
    if (newSelection != null) {
      LoggingService.instance.debug('Selecting marker with ID: ${newSelection.activity.firebaseId}');
      map.setFeatureState(
        "activity-source",
        null,
        newSelection.activity.firebaseId,
        jsonEncode({"selected": true}),
      );
    }
  }

My layer is init like that

Future<void> _initSymbolLayer() async {
    await map.style.addStyleSource(
        "activity-source",
        jsonEncode({
          'type': 'geojson',
          'data': {
            'type': 'FeatureCollection',
            'features': [],
          },
        }));

    await map.style.addStyleLayer(
      jsonEncode(
        {
          'id': "activity-layer",
          'type': 'symbol',
          'source': "activity-source",
          'layout': {
            'text-field': ['get', 'title'],
            'text-size': OGDims.dim4,
            'text-variable-anchor': ['left', 'top', 'right'],
            'text-radial-offset': 1,
            'text-offset': [2, 0],
            'icon-image': [
              'case',
              [
                'boolean',
                ['feature-state', 'selected'],
                false
              ],
              ['get', 'selectedIcon'],
              ['get', 'icon'],
            ],
            'icon-size': 7,
            'icon-allow-overlap': true,
            'icon-ignore-placement': true,
            'text-allow-overlap': false,
            'text-ignore-placement': false,
            'text-justify': "auto",
          },
          'paint': {
            'text-color': "#000000",
            'text-halo-color': "#FFFFFF",
            'text-halo-width': 1.75,
            'icon-opacity': [
              'coalesce',
              ['feature-state', 'opacity'],
              0.0
            ]
          }
        },
      ),
      LayerPosition(at: 0),
    );

    addMarkerImagesToMap();
  }

But I can't make it works. Is it a bad implementation or a bug?