How to retrieve android API version programmatically?

This example demonstrates how do I retrieve android API version programmatically.
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.
<?xml version="1.0" encoding="utf-8"?>
<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"
   tools:context=".MainActivity">
   <TextView
      android:id="@+id/textView"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text=""
      android:layout_above="@id/button"
      android:layout_centerInParent="true"
      android:layout_marginBottom="12sp"
      android:textSize="24sp"
      android:textStyle="bold|italic" />
   <Button
      android:id="@+id/button"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:textSize="16sp"
      android:textStyle="bold"
      android:text="Get Android API Version" />
</RelativeLayout>
Step 3 − Add the following code to src/MainActivity.java
import android.os.Build;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
   Button button;
   TextView textView;
   int androidVersion;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      textView = findViewById(R.id.textView);
      button = findViewById(R.id.button);
      button.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            androidVersion = Build.VERSION.SDK_INT;
            switch (androidVersion) {
               case 14:
                  textView.setText("15, Ice Cream Sandwich");
               break;
               case 15:
                  textView.setText("15, Ice Cream Sandwich");
               break;
               case 16:
                  textView.setText("16, Jelly Bean");
               break;
               case 17:
                  textView.setText("17, Jelly Bean");
               break;
               case 18:
                  textView.setText("18, Jelly Bean");
               break;
               case 19:
                  textView.setText("19, KitKat");
               break;
               case 21:
                  textView.setText("21, Lollipop");
               break;
               case 22:
                  textView.setText("22, Lollipop");
               break;
               case 23:
                  textView.setText("23, Marshmallow");
               break;
               case 24:
                  textView.setText("24, Nougat");
               break;
               case 25:
                  textView.setText("25, Nougat");
               break;
               case 26:
                  textView.setText("26, Oreo");
               break;
               default:
                  Toast.makeText(MainActivity.this, "Not Found", Toast.LENGTH_LONG).show();
               break;
            }
         }
      });
   }
}
Step 4 − Add the following code to androidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest
   xmlns:android="http://schemas.android.com/apk/res/android"
   package="app.com.sample">
   <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 Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen −