Programmatically change map style in MapboxGL native with swift.

mbxstyle.swift

// Using SwiftyJSON

var path = NSBundle.mainBundle().pathForResource("satellite-v7-debug", ofType: "json")
var styles = NSData(contentsOfFile: path!)
var jsonStyles = JSON(data: styles!)

let polygonCoordinates = [
    [
        8.702266216278076,
        56.04999222180692
    ],
    [
        8.7001633644104,
        56.04860211635043
    ],
    [
        8.700292110443115,
        56.04260970914898
    ],
    [
        8.706600666046143,
        56.04241793674957
    ],
    [
        8.706622123718262,
        56.0457977856487
    ],
    [
        8.705828189849854,
        56.04718799216029
    ],
    [
        8.70490550994873,
        56.048542196885634
    ],
    [
        8.70391845703125,
        56.04945296270642
    ],
    [
        8.702266216278076,
        56.04999222180692
    ]
]

var json:JSON = [
    "type": "geojson",
    "data": [
        "type": "FeatureCollection",
        "features": [
            [
                "type": "Feature",
                "properties": [:],
                "geometry": [
                    "type": "Polygon",
                    "coordinates": polygonCoordinates
                ]
            ]
        ]
    ],
    "properties": [
        "title": "My field",
        "marker-symbol": "monument"
    ]
]

var layer:JSON = [
    "id": "polygon_drawn",
    "type": "fill",
    "source": "polygon",
    "source-layer": "polygon layer",
    "paint": [
        "fill-color": "#ffffcc"
    ]
]

jsonStyles["sources"].dictionaryObject?.updateValue(json.object, forKey: "polygon")
jsonStyles["layers"].arrayObject?.append(layer.object)

println("polygon \(json.rawString(encoding: NSUTF8StringEncoding, options: NSJSONWritingOptions.allZeros))")

mapView!.setStyleJSON(jsonStyles.rawString(encoding: NSUTF8StringEncoding, options: NSJSONWritingOptions.allZeros))