AsyncTask in Android with Kotlin

Question

How to make an API call in Android with Kotlin?

I have heard of Anko . But I want to use methods provided by Kotlin like in Android we have Asynctask for background

Answer 1

if in the case you want to do it without using Anko and the correct way is to use the following way

open class PromotionAsyncTask : AsyncTask>() {

private lateinit var out: FileOutputStream
private lateinit var bitmap: Bitmap
private lateinit var directory: File
private var listPromotion: MutableList = mutableListOf()

override fun doInBackground(vararg params: JsonArray?): MutableList {

    directory = Environment.getExternalStoragePublicDirectory("Tambo")

    if (!directory.exists()) {
        directory.mkdirs()
    }

    for (x in listFilesPromotion(params[0]!!)) {
        bitmap = BitmapFactory.decodeStream(URL(x.url).content as InputStream)
        out = FileOutputStream(File(directory, "${x.name}"))

        bitmap.compress(Bitmap.CompressFormat.PNG, 100, out)
        out.flush()
        out.close()

        listPromotion.add(File(directory, "${x.name}").toString())
    }

    return listPromotion
}

private fun listFilesPromotion(jsonArray: JsonArray): MutableList {
    var listString = mutableListOf()

    for (x in jsonArray) {
        listString.add(Promotion(x.asJsonObject.get("photo")
                .asString.replace("files/promos/", "")
                , "https://tambomas.pe/${x.asJsonObject.get("photo").asString}"))
    }

    return listString}
}

and the way to execute it is as follows

promotionAsyncTask = object : PromotionAsyncTask() {
                    override fun onPostExecute(result: MutableList?) {
                        super.onPostExecute(result)
                        listFile = result!!

                        contentLayout.visibility = View.VISIBLE
                        progressLottie.visibility = View.GONE
                    }
                }
                promotionAsyncTask.execute(response!!.body()!!.asJsonObject.get("promos").asJsonArray)