How to detect orientation change in layout in android?

This example demonstrates how do I detect orientation change in layout in android.

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"?>
<LinearLayout 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">
<TextView
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="Hello World!"
   android:textSize="24sp"
   android:textStyle="bold"/>
</LinearLayout>

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

import androidx.appcompat.app.AppCompatActivity;
import android.content.res.Configuration;
import android.os.Bundle;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
   }
   @Override
   public void onConfigurationChanged(Configuration newConfig) {
      super.onConfigurationChanged(newConfig);
      if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
         Toast.makeText(MainActivity.this, "Landscape Mode", Toast.LENGTH_SHORT).show();
      } else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) {
         Toast.makeText(MainActivity.this, "Portrait Mode", Toast.LENGTH_SHORT).show();
      }
   }
}

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" android:configChanges="orientation|screenSize">
         <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 the 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 −