Feature request: layer style expressions about mapbox-maps-flutter HOT 9 CLOSED

@geisterfurz007 Thanks, well spottet. I wish it made a difference. I tried all combinations with await only, then() only, both together. But the layer is never found.

UPDATE: It's the geojsonHeatmap.existsSync() that was causing the issue!

from mapbox-maps-flutter.

This can already be achieved with interpolate:

{
    "circle-radius": [
        "interpolate", ["linear"], ["zoom"],
        // zoom is 5 (or less) -> circle radius will be 1px
        5, 1,
        // zoom is 10 (or greater) -> circle radius will be 5px
        10, 5
    ]
}

from mapbox-maps-flutter.

Hi, thanks for your reply.

Yeah, we used to use interpolate for that.
I just couldn't find mention of any layer styles in the readme or demo app.
Now searching for interpolate in the project I see it gets used with layer styles once. A bit of hay in a needle stack.

Thanks for this! Perhaps it can be mentioned in the readme?
I think most devs new to Mapbox wouldn't be aware of layer styles or even think to search for them in the demo app.

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@irjayjay hey, there's not a lot of docs about expressions usage at the moment (though seems you've found the animated route page that uses interpolate).
We'll definitely work on adding more!

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Hi there. I think for expression usage a simple link to the mapbox docs would be fine.
I was referring more to mentioning in the readme that you can create layers and layer styles the traditional way.

But I see it's already there. I don't know how I missed that before.

Once again, thanks for all the great work!

from mapbox-maps-flutter.

Can this "traditional way" also be used for the HeatmapLayer?

With mapboxMap.style.setStyleLayerProperty I only get: Unhandled Exception: PlatformException(StyleError(rawValue: "Layer heatmap is not in style"), null, null, null)

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@demux79 Make sure the layer is added to the styles before you try to set the style layer property; for that, make sure to await the call to addLayer.

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@geisterfurz007 Hi, thanks for getting back to me. Unfortunately, I am already awaiting everything but still get the error. Do you have an idea? Also the styleSourceExists in line 6 is never true.

void _onStyleLoaded(StyleLoadedEventData styleLoadedEventData) async {
    await _addLayerAndSource();
  }

  Future<void> _addLayerAndSource() async {
    await mapboxMap?.style.styleSourceExists("source").then((exists) async {
      if (!exists) {
        // TODO: Is never called for unknown reasons
        // If source exists - just update it
        // final source = await mapboxMap?.style.getSource("source");
        // (source as GeoJsonSource).updateGeoJSON(json.encode(geojsonHeatmap));
        // } else {
        await mapboxMap?.style.addSource(GeoJsonSource(
            id: "source", data: geojsonHeatmap.readAsStringSync()));
      }
    });

    mapboxMap?.style.styleLayerExists("heatmap").then((exists) async {
      if (!exists && geojsonHeatmap.existsSync()) {
        await mapboxMap?.style.addLayer(HeatmapLayer(
          id: 'heatmap',
          sourceId: 'source',
          minZoom: 4.0,
          heatmapIntensity: 0.1,
          heatmapOpacity: 0.5,
          heatmapRadius: 30,
          heatmapWeight: 1.0,
        ));
      }
    });

    await mapboxMap?.style.setStyleLayerProperty('heatmap', 'heatmap-radius', 40);
  }

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@demux79 There is one await missing at the second larger block in front of mapboxMap?.style.styleLayerExists.

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