How to Create a Custom Intro Slider of an Android App?

package org.geeksforgeeks.demo;

public class SliderModal {

    private String title;
    private String heading;
    private int imgUrl;

    public SliderModal(String title, String heading, int imgUrl) {
        this.title = title;
        this.heading = heading;
        this.imgUrl = imgUrl;
    }

    public String getTitle() {
        return title;
    }

    public String getHeading() {
        return heading;
    }

    public int getImgUrl() {
        return imgUrl;
    }
}

package org.geeksforgeeks.demo;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.viewpager.widget.PagerAdapter;

import com.bumptech.glide.Glide;

import java.util.ArrayList;

public class SliderAdapter extends PagerAdapter {

    private Context context;
    private ArrayList<SliderModal> sliderModalArrayList;
    // LayoutInflater to inflate custom layout
    private LayoutInflater layoutInflater;

    public SliderAdapter(Context context, ArrayList<SliderModal> sliderModalArrayList) {
        this.context = context;
        this.sliderModalArrayList = sliderModalArrayList;
    }

    // Returns the total number of items
    @Override
    public int getCount() {
        return sliderModalArrayList.size();
    }

    // Checks whether a page View is associated with a specific key object
    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }

    // Instantiates and returns a page View object
    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = layoutInflater.inflate(R.layout.slider_layout, container, false);

        // Initialize views
        ImageView imageView = view.findViewById(R.id.imageView);
        TextView titleTV = view.findViewById(R.id.titleTextView);
        TextView headingTV = view.findViewById(R.id.descriptionTextView);

        // Set data to views
        SliderModal modal = sliderModalArrayList.get(position);
        titleTV.setText(modal.getTitle());
        headingTV.setText(modal.getHeading());
        Glide.with(context).load(modal.getImgUrl()).into(imageView);

        // Add the view to container
        container.addView(view);
        return view;
    }

    // Removes a page View from the container
    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((View) object);
    }
}

package org.geeksforgeeks.demo;

import android.os.Bundle;
import android.text.Html;
import android.widget.LinearLayout;
import android.widget.TextView;

import androidx.activity.ComponentActivity;
import androidx.activity.enableEdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import androidx.viewpager.widget.ViewPager;
import androidx.viewpager.widget.ViewPager.OnPageChangeListener;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    private ViewPager viewPager;
    private LinearLayout dotsLL;
    private SliderAdapter adapter;
    private ArrayList<SliderModal> sliderModalArrayList;
    private TextView[] dots;
    private int size = 0;

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

        // Initialize views
        viewPager = findViewById(R.id.idViewPager);
        dotsLL = findViewById(R.id.dotsLayout);

        // Create and populate slider items
        sliderModalArrayList = new ArrayList<>();
        sliderModalArrayList.add(new SliderModal("Slide 1", "Slide 1 heading", R.drawable.sample1));
        sliderModalArrayList.add(new SliderModal("Slide 2", "Slide 2 heading", R.drawable.sample2));
        sliderModalArrayList.add(new SliderModal("Slide 3", "Slide 3 heading", R.drawable.sample3));

        // Set up adapter with slider items
        adapter = new SliderAdapter(this, sliderModalArrayList);
        viewPager.setAdapter(adapter);

        // Get the total number of slides
        size = sliderModalArrayList.size();

        // Add initial dot indicators
        addDots(size, 0);

        // Set page change listener
        viewPager.addOnPageChangeListener(viewListener);
    }

    // Method to add and update dot indicators
    private void addDots(int size, int pos) {
        dots = new TextView[size];
        dotsLL.removeAllViews();

        for (int i = 0; i < size; i++) {
            dots[i] = new TextView(this);
            dots[i].setText(Html.fromHtml("•"));
            dots[i].setTextSize(35f);
            dots[i].setTextColor(ContextCompat.getColor(this, R.color.black));
            dotsLL.addView(dots[i]);
        }

        // Highlight selected dot
        if (dots.length > 0) {
            dots[pos].setTextColor(ContextCompat.getColor(this, R.color.colorPrimary));
            dots[pos].setTextSize(45f);
        }
    }

    // Page change listener to update dots on slide change
    private final OnPageChangeListener viewListener = new OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}

        @Override
        public void onPageSelected(int position) {
            addDots(size, position);
        }

        @Override
        public void onPageScrollStateChanged(int state) {}
    };
}