How to add linewidth property to MGLFillStyleLayer in mapbox ios sdk?

问题

I have to add polygon features in the 'MGLFillStyleLayer' with 'MGLPolygonFeature' but the problem is I can't change the outline width.

回答1:

The line width for a MGLFillStyleLayer currently cannot be changed. The suggested workaround is to use the same source to create a MGLLineStyleLayer, then insert the line layer above the fill layer.

I can add a line layer to this example with the following code:

    let lineLayer = MGLLineStyleLayer(identifier: "line-layer", source: source)
    lineLayer.lineWidth = MGLStyleValue(rawValue: 5)
    lineLayer.sourceLayerIdentifier = "drone-restrictions-3f6lsg"

    if let cityLabels = style.layer(withIdentifier: "place-city-sm") {
        style.insertLayer(layer, below: cityLabels)
        style.insertLayer(lineLayer, above: layer)
    }

来源：https://stackoverflow.com/questions/48636433/how-to-add-linewidth-property-to-mglfillstylelayer-in-mapbox-ios-sdk