kotlin スピナー（リストボックス）を使う

スピナーアイテムはarrayを作成して使用する、もしくはresouceファイル（strings.xml）にstring-arrayを作成して使用します。
スピナーで選択されたらテキストビューに内容を表示しています。


            package com.example.samplespinner

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.AdapterView
import android.widget.ArrayAdapter
import com.example.samplespinner.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity(), AdapterView.OnItemSelectedListener { // *1
    private lateinit var binding: ActivityMainBinding
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        // case of make array.
        val myArray = 0..9
        val adapter = ArrayAdapter(
            this,
            android.R.layout.simple_spinner_item,
            myArray.toList()
        )
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
        binding.spnSample.adapter = adapter
        binding.spnSample.onItemSelectedListener = this

        // case of get from resource.
        val adapter2 = ArrayAdapter.createFromResource(
            this,
            R.array.my_array,
            android.R.layout.simple_spinner_item
        )
        adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
        binding.spnSample2.adapter = adapter2
        binding.spnSample2.onItemSelectedListener = this
    }

    override fun onItemSelected(parent: AdapterView<*>?, view: View?, pos: Int, id: Long) { // *2
        when (parent) {
            binding.spnSample -> {
                var str = "spinner1 clicked."
                str += "\npos:$pos"
                str += "\n" + parent.selectedItem.toString()
                binding.txvSample.text = str
            }

            binding.spnSample2 -> {
                var str = "spinner2 clicked."
                str += "\npos:$pos"
                str += "\n" + parent.selectedItem.toString()
                binding.txvSample.text = str
            }
        }
    }

    override fun onNothingSelected(p0: AdapterView<*>?) {
        // do nothing.
    }
}

kotlin スピナー（リストボックス）を使う

MainActivity.kt

strings.xml