[Android] Stored your customized data object in Spinner with Kotlin

If you want to make the list of your customized data objects be stored in Spinner. Try this...

Step:

1. write your own data class
2. override the toString() method of your data class
3. add it to mutable list
4. write on onItemSelected listener
5. get selected item, and retrieval the object of your data class

Your data class

class MenuData(var menuName: String
               , var waterLevel: String  // small, standard, long
               , var foamLevel: String   // none, standard, thick
               , var grindLevel: String  // fine, medium, coarse
               , var tasteLevel: String  // mild, standard, strong
               , var menuId: Long        // ID on web server
               , var menuType: String    // general, customized
) {
    /**
    for displaying by spinner text, you should override toString()
    */
    override fun toString(): String {
        return menuName
    }
}

Menu.kt

import android.app.Activity
import android.content.DialogInterface
import android.os.Bundle
import android.view.View
import android.widget.*

import org.json.JSONArray
import com.loopj.android.http.AsyncHttpClient
import com.loopj.android.http.AsyncHttpResponseHandler
import com.loopj.android.http.RequestParams
import cz.msebera.android.httpclient.Header

class Menu : Activity() {
    private var serverDestination: String? = null
    private var spnMenu: Spinner? = null
    private var menuAdapter: ArrayAdapter? = null
    private val menuList: MutableList = mutableListOf()

    override fun onCreate(savedInstanceState: Bundle?) {
        val bundle = this.intent.extras
        m_accessToken = bundle!!.getString("accessToken")
        m_refreshToken = bundle.getString("refreshToken")


        super.onCreate(savedInstanceState)
        spnMenu = findViewById(R.id.spi_CoffeeMenuCloud)
        invoke_InitMenu("$serverDestination/menu")
        spnMenu!!.onItemSelectedListener = spnMenuListener
    }

    fun invoke_InitMenu(url: String) {
        val temp = "Bearer " + m_accessToken!!

        val client = AsyncHttpClient()
        client.addHeader("authorization", temp)
        client.addHeader("Content-Type", "application/json")

        client.get(url, object : AsyncHttpResponseHandler() {
            override fun onSuccess(statusCode: Int, headers: Array
, responseBody: ByteArray) {
                val data = String(responseBody)

                // Decoding downloaded menu data

                try {
                    val mJMenu = JSONArray(data)
                    val userMenuCount = mJMenu.length()
                    menuList.clear()
                    if (userMenuCount > 0) {
                        for (i in 0 until userMenuCount) {
                            val mJMenuTmp = mJMenu.getJSONObject(i)
                            val menuId = mJMenuTmp.getLong("menu_id")
                            val menuName = mJMenuTmp.getString("name")
                            val menuWaterLevel = mJMenuTmp.getString("water_level")
                            val menuFoamLevel = mJMenuTmp.getString("foam_level")
                            val menuTasteLevel = mJMenuTmp.getString("taste_level")
                            val menuGrindSize = mJMenuTmp.getString("grind_size")
                            val menuType = mJMenuTmp.getString("menu_type")

                            val menuItem = MenuData(menuName, menuWaterLevel, menuFoamLevel,
                                    menuGrindSize, menuTasteLevel, menuId, menuType)
                            menuList.add(menuItem)
                        }
                    }

                    menuAdapter = ArrayAdapter(this@Menu, android.R.layout.simple_spinner_item, menuList)
                    menuAdapter!!.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
                    menuAdapter!!.notifyDataSetChanged()
                    spnMenu!!.adapter = menuAdapter
                } catch (err_Mag: Exception) {
                    Toast.makeText(applicationContext, err_Mag.message, Toast.LENGTH_LONG).show()
                }

                Toast.makeText(applicationContext, "Menu sync successful.", Toast.LENGTH_LONG).show()
            }

            override fun onFailure(statusCode: Int, headers: Array
, responseBody: ByteArray, error: Throwable) {
                Toast.makeText(applicationContext, "Menu sync failed.", Toast.LENGTH_LONG).show()
            }
        })

    }


    private val spnMenuListener = object : AdapterView.OnItemSelectedListener {
        override fun onItemSelected(parent: AdapterView<*>, view: View, position: Int, id: Long) {
            val menuId = menuList[position].menuId
            Toast.makeText(this@Menu, "Menu ID: $menuId", Toast.LENGTH_SHORT).show()
            val tasteLevel = menuList[position].tasteLevel
            Toast.makeText(this@Menu, "Taste level: $tasteLevel", Toast.LENGTH_SHORT).show()

        }

        override fun onNothingSelected(parent: AdapterView<*>) {

        }
    }

}