How can I parse data from a JSON file into a new GeoJSON in Kotlin?

Question

I am completely new to Kotlin and I have a task that I am trying to perform and cannot seem to find much documentation. I have coded what I need to do in JavaScript (see below), but I need to convert the same functionality to Kotlin. Basically, I have JSON file that contains coordinates within it. I need to extract these coordinates and push them into a brand new GeoJson variable. This is the code I need to convert, how can I go about doing this?

let routeTemp = {
    'type': 'FeatureCollection',
    'features': []
}

let geoTemp = {
        'type': 'Feature',
        'properties': {},
        'geometry': {
            'type': 'LineString',
            'coordinates': [],
        }
    };

function jsonToGeo(data) {
    for(track in data.track) {
        let coords = [data.track[track].Lon, data.track[track].Lat];
        geoTemp.geometry['coordinates'].push(coords);
    }
    routeTemp['features'].push(geoTemp);
}

Answer 1

My solution I ended up coming up with...

Make sure to import this:

import org.json.JSONObject

I defined my JSON as a string globally, and then used it to construct a JSON Object:

val jsonObject = JSONObject(jsonStr) // convert JSON string into JSON Object

Include this in the onCreate function:

val coordsLine =  parseJsonL()
val  geoStr = geoTemp(coordsLine)

Then define these functions:

// function to parse line coordinates from JSON
fun parseJsonL(): ArrayList<String> {
    // extract tracks as an array from JSON
    val trackArray = jsonObject.getJSONArray("track")
    val coordList = ArrayList<String>()
    // iterate through coordinates for each track, extract as strings, and add to a list
    for (i in 0 until trackArray.length()) {
        val coordsL = trackArray.getJSONObject(i)
        val lon = coordsL.getString("Lon")
        val lat = coordsL.getString("Lat")
        coordList.add("[$lon, $lat]")
    }
    return coordList
}

// function to insert coordinates into GeoJSON template
fun geoTemp(coordsLine: ArrayList<String>): String {
    val geoStr = """
            {
                "type": "FeatureCollection",
                "features": [
                    {
                        "type": "Feature",
                        "properties": {
                            "name": "Sea Wall Route"
                        },
                        "geometry": {
                            "type": "LineString",
                            "coordinates": $coordsLine
                        }
                    }
                ]
            }
        """.trimIndent()
    return geoStr
}

I'm open to suggestions for improving this code since, again, I'm very new to Kotlin :)