How to change spinner text size and text color in Android App using Kotlin?

This example demonstrates how to change spinner text size and text color in Android App using Kotlin.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:gravity="center"
   tools:context=".MainActivity">  
   <Spinner
      android:id="@+id/spinner"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.kt

import android.os.Bundle
import android.widget.ArrayAdapter
import android.widget.Spinner
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
   lateinit var spinner: Spinner
      override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      spinner = findViewById(R.id.spinner)
      val superHero = arrayOf<String?>("Batman", "SuperMan", "Flash", "AquaMan", "Shazam")
      val arrayAdapter: ArrayAdapter<Any?> = ArrayAdapter<Any?>(this, R.layout.spinner_list, superHero)
      arrayAdapter.setDropDownViewResource(R.layout.spinner_list)
      spinner.adapter = arrayAdapter
   }
}

Step 4 − Create a layout resource file and add the following code in spinner_list.xml

Example

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:padding="10dp"
   android:textColor="@android:color/holo_red_light"
   android:textSize="16sp"
   android:textStyle="bold|italic" />

Step 5 − Add the following code to androidManifest.xml

Example

<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="app.com.q11">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen.