Create an Expandable Notification Containing a Picture in Android

package com.gfg.android_notification;

import android.Manifest;
import android.annotation.SuppressLint;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.app.NotificationCompat;
import androidx.core.app.NotificationManagerCompat;

public class MainActivity extends AppCompatActivity {

    private Button button;
    private static final String CHANNEL_ID = "i.apps.notifications";
    private static final int NOTIFICATION_ID = 1234;
    private static final String CHANNEL_NAME = "Test notification";
    private static final int REQUEST_CODE_POST_NOTIFICATIONS = 101;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        button = findViewById(R.id.button);

        // Create a notification channel (required for Android 8.0 and higher)
        createNotificationChannel();

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // Request runtime permission for notifications on Android 13 and higher
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
                    if (ActivityCompat.checkSelfPermission(
                            MainActivity.this,
                            Manifest.permission.POST_NOTIFICATIONS
                    ) != PackageManager.PERMISSION_GRANTED) {
                        ActivityCompat.requestPermissions(
                                MainActivity.this,
                                new String[]{Manifest.permission.POST_NOTIFICATIONS},
                                REQUEST_CODE_POST_NOTIFICATIONS
                        );
                        return;
                    }
                }
                // Trigger the notification
                sendNotification();
            }
        });
    }

    /**
     * Create a notification channel for devices running Android 8.0 or higher.
     * A channel groups notifications with similar behavior.
     */
    private void createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel notificationChannel = new NotificationChannel(
                    CHANNEL_ID,
                    CHANNEL_NAME,
                    NotificationManager.IMPORTANCE_HIGH
            );
            // Turn on notification light
            notificationChannel.enableLights(true);
            notificationChannel.setLightColor(Color.GREEN);
            // Allow vibration for notifications
            notificationChannel.enableVibration(true);

            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            notificationManager.createNotificationChannel(notificationChannel);
        }
    }

    /**
     * Build and send a notification with a custom layout and action.
     */
    @SuppressLint("MissingPermission")
    private void sendNotification() {
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.gfg_logo);

        // Build the notification
        NotificationCompat.Builder builder = new NotificationCompat.Builder(this, CHANNEL_ID)
                .setSmallIcon(R.drawable.gfg_logo) // Notification icon
                .setContentTitle("GeeksforGeeks") // Title displayed in the notification
                .setContentText("Expand to see image") // Text displayed in the notification
                .setAutoCancel(true) // Dismiss notification when tapped
                .setPriority(NotificationCompat.PRIORITY_DEFAULT) // Notification priority for better visibility
                .setStyle(new NotificationCompat.BigPictureStyle() // use BigPictureStyle() to add a large image
                        .bigPicture(bitmap)); // add a icon or a bitmap image

        // Display the notification
        NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
        notificationManager.notify(NOTIFICATION_ID, builder.build());
    }
}