android spinner example kotlin

android spinner example - string array xml

res/values/strings.xml

<resources>
    <string name="app_name">KotlinSpinnerExample</string>

    <string-array name="country_arrays">
        <item>India</item>
        <item>United States</item>
        <item>Indonesia</item>
        <item>France</item>
        <item>China</item>
        <item>Japan</item>
        <item>New Zealand</item>
        <item>Other</item>
    </string-array>

</resources>

Populate the Spinner with string array choices

With an array such as mentioned above, you can use below code in your Activity or Fragment to set spinner with the string array using an ArrayAdapter instance:

package com.example.kotlinspinnerexample

import androidx.appcompat.app.AppCompatActivity

import android.os.Bundle
import android.view.View
import android.widget.AdapterView
import android.widget.ArrayAdapter
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_main.*
class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        setSimpleSpinner()
    }

    fun setSimpleSpinner() {
        // Create an ArrayAdapter using the string array (country_arrays) and a default spinner layout
        ArrayAdapter.createFromResource(
                this,
                R.array.country_arrays,
                android.R.layout.simple_spinner_item
        ).also { adapter ->
            // Specify the layout to use when the list of choices appears
            adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
            // Apply the adapter to the spinner
            spinner.adapter = adapter
        }

       spinner.setOnItemSelectedListener(object : AdapterView.OnItemSelectedListener {
            override fun onItemSelected(parent: AdapterView<*>?, p1: View?, pos: Int, p3: Long) {
                Toast.makeText(this@MainActivity, "" + parent?.getItemAtPosition(pos).toString(), Toast.LENGTH_SHORT).show()
            }
            override fun onNothingSelected(p0: AdapterView<*>?) {
            }
        })
    }
}

Here, I have put the spinner inside the ConstraintLayout and guildeline is on both sides. ConstraintLayout  has white background  and wraps AppCompatSpinner. So I can highlight the spinner according to background (background is grey here).
activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:background="#f3f3f3">

    <androidx.constraintlayout.widget.Guideline
        android:id="@+id/guidelineStart"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_begin="16dp" />

    <androidx.constraintlayout.widget.Guideline
        android:id="@+id/guidelineEnd"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_end="16dp" />

    <com.google.android.material.textview.MaterialTextView
        android:id="@+id/tv_selected_item"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:hint="Select Country from below spinner"
        android:textColorHint="#000000"
        app:layout_constraintEnd_toEndOf="@id/guidelineEnd"
        app:layout_constraintStart_toStartOf="@id/guidelineStart"
        app:layout_constraintTop_toTopOf="parent">
    </com.google.android.material.textview.MaterialTextView>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@+id/cl_spinner"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:background="#ffffff"
        android:padding="5dp"
        app:layout_constraintEnd_toEndOf="@id/guidelineEnd"
        app:layout_constraintStart_toStartOf="@+id/guidelineStart"
        app:layout_constraintTop_toBottomOf="@id/tv_selected_item">

        <androidx.appcompat.widget.AppCompatSpinner
            android:id="@+id/spinner"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </androidx.constraintlayout.widget.ConstraintLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

android kotlin - Spinner example

Populate the Spinner with country string array

how to set value in spinner dynamically in android

var country_list = arrayListOf<String>()

        country_list.add("India")
        country_list.add("United States")
        country_list.add("Indonesia")
        country_list.add("France")
        country_list.add("China")
        country_list.add("Japan")
        country_list.add("New Zealand")
        country_list.add("Other")

val adapter = ArrayAdapter(
                this, // Context
                android.R.layout.simple_spinner_dropdown_item, // Layout
                country_list // ArrayList
        )

spinner.adapter = adapter