How can I parse Nested JSON with dynamic keys in Android kotlin, Moshi and Retrofit?

Question

How can I parse Nested JSON with NESTED dynamic keys in Android kotlin, Moshi and Retrofit?

I get this JSON from alpha-vantage.

Format example:

{
    "Meta Data": {
        "1. Information": "Intraday (15min) open, high, low, close prices and volume",
        "2. Symbol": "AAME",
        "3. Last Refreshed": "2019-11-18 16:00:00",
        "4. Interval": "15min",
        "5. Output Size": "Compact",
        "6. Time Zone": "US/Eastern"
     },
    "Time Series (15min)": {//Dynamic - > Time Series (5min) / Time Series (30min)
        "2019-11-18 16:00:00": {//Dynamic
            "1. open": "1.6700",
            "2. high": "1.6700",
            "3. low": "1.5700",
            "4. close": "1.5700",
            "5. volume": "1521"
        },
        "2019-11-18 15:45:00": {//Dynamic
            "1. open": "1.6600",
            "2. high": "1.7400",
            "3. low": "1.6600",
            "4. close": "1.7400",
            "5. volume": "355"
        }
    }
}

I tried to use custom adapter but I can't find a way to parse a double nested dynamic keys with it. For now I use manual parsing:

fun convertJsonToItemDetails(jso: JSONObject) {
    val meta: JSONObject? = jso.optJSONObject("Meta Data")
    var metaData: ItemMetaData? = null
    meta?.apply {
        val information = optString("1. Information")
        val symbol = optString("2. Symbol")
        val lastRefreshed = optString("3. Last Refreshed")
        val interval = optString("4. Interval")
        val outputSize = optString("5. Output Size")
        val timeZone = optString("6. Time Zone")
        metaData =
            ItemMetaData(information, symbol, lastRefreshed, interval, outputSize, timeZone)
    }
    if (metaData == null) {
        //TODO return error object
        return
    }

    val timeSeriesJSON = jso.optJSONObject("Time Series (${metaData?.interval})")
    val timeSeires = HashMap<String, IntervalOutput>()
    if (timeSeriesJSON == null) {
        //TODO return error object
        return
    }
    for (key in timeSeriesJSON.keys()) {
        val intervalOutPutJSON = timeSeriesJSON.getJSONObject(key)
        val open = intervalOutPutJSON.getString("1. open")
        val high = intervalOutPutJSON.getString("2. high")
        val low = intervalOutPutJSON.getString("3. low")
        val close = intervalOutPutJSON.getString("4. close")
        val volume = intervalOutPutJSON.getString("5. volume")
        timeSeires[key] = IntervalOutput(open, high, low, close, volume)
    }
    val itemDetails = ItemDetails(metaData, timeSeires)
    _itemDetails.value = itemDetails
}

Answer 1

Use JSONObject keys() to get the Dynamic Keys and then Iterate each particular key to get to the dynamic value.

A very short to print all the JSONObject of 1st Tier is look like this.

var dynamicJSON: String = {
    "Meta Data": {
        "1. Information": "Intraday (15min) open, high, low, close prices and volume",
        "2. Symbol": "AAME",
        "3. Last Refreshed": "2019-11-18 16:00:00",
        "4. Interval": "15min",
        "5. Output Size": "Compact",
        "6. Time Zone": "US/Eastern"
     },
    "Time Series (15min)": {//Dynamic - > Time Series (5min) / Time Series (30min)
        "2019-11-18 16:00:00": {//Dynamic
            "1. open": "1.6700",
            "2. high": "1.6700",
            "3. low": "1.5700",
            "4. close": "1.5700",
            "5. volume": "1521"
        },
        "2019-11-18 15:45:00": {//Dynamic
            "1. open": "1.6600",
            "2. high": "1.7400",
            "3. low": "1.6600",
            "4. close": "1.7400",
            "5. volume": "355"
        }
    }
}  

Then After you have to start parsing it as JSONObject and then further follows the same process for the JSONObject "Meta Data" & "Time Series (15min)"

val dynamicjson: JSONObject = JSONObject(dynamicJSON)
val keys: Iterator<*> = dynamicjson.keys()

while (keys.hasNext()) { // loop to get the dynamic key
   val currentDynamicKey = keys.next() as String
   // get the value of the dynamic key
   val currentDynamicValue: JSONObject = dynamicjson.getJSONObject(currentDynamicKey)
   // do something here with the value... or either make another while loop to Iterate further

   Log.e("JSON Value", currentDynamicValue.toString())
}

The OUTPUT looks like this when I executed the code:

2019-12-12 15:21:08.399 19798-19798/com.animusabhi.dynamicjsonparsing E/JSON Value: {"1. Information":"Intraday (15min) open, high, low, close prices and volume","2. Symbol":"AAME","3. Last Refreshed":"2019-11-18 16:00:00","4. Interval":"15min","5. Output Size":"Compact","6. Time Zone":"US/Eastern"}

2019-12-12 15:21:09.158 19798-19798/com.animusabhi.dynamicjsonparsing E/JSON Value{"2019-11-18 16:00:00":{"1. open":"1.6700","2. high":"1.6700","3. low":"1.5700","4. close":"1.5700","5. volume":"1521"},"2019-11-18 15:45:00":{"1. open":"1.6600","2. high":"1.7400","3. low":"1.6600","4. close":"1.7400","5. volume":"355"}}

check and let me know if it not works.