Level SelectorCreating a Level Select Screen in C#

Source Code for LevelSelector.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using TMPro;

public class LevelSelector : MonoBehaviour{
    public GameObject levelHolder;
    public GameObject levelIcon;
    public GameObject thisCanvas;
    public int numberOfLevels = 50;
    public Vector2 iconSpacing;
    private Rect panelDimensions;
    private Rect iconDimensions;
    private int amountPerPage;
    private int currentLevelCount;

    // Start is called before the first frame update
    void Start(){
        panelDimensions = levelHolder.GetComponent<RectTransform>().rect;
        iconDimensions = levelIcon.GetComponent<RectTransform>().rect;
        int maxInARow = Mathf.FloorToInt((panelDimensions.width + iconSpacing.x) / (iconDimensions.width + iconSpacing.x));
        int maxInACol = Mathf.FloorToInt((panelDimensions.height + iconSpacing.y) / (iconDimensions.height + iconSpacing.y));
        amountPerPage = maxInARow * maxInACol;
        int totalPages = Mathf.CeilToInt((float)numberOfLevels / amountPerPage);
        LoadPanels(totalPages);
    }
    void LoadPanels(int numberOfPanels){
        GameObject panelClone = Instantiate(levelHolder) as GameObject;
        PageSwiper swiper = levelHolder.AddComponent<PageSwiper>();
        swiper.totalPages = numberOfPanels;

        for(int i = 1; i <= numberOfPanels; i++){
            GameObject panel = Instantiate(panelClone) as GameObject;
            panel.transform.SetParent(thisCanvas.transform, false);
            panel.transform.SetParent(levelHolder.transform);
            panel.name = "Page-" + i;
            panel.GetComponent<RectTransform>().localPosition = new Vector2(panelDimensions.width * (i-1), 0);
            SetUpGrid(panel);
            int numberOfIcons = i == numberOfPanels ? numberOfLevels - currentLevelCount : amountPerPage;
            LoadIcons(numberOfIcons, panel);
        }
        Destroy(panelClone);
    }
    void SetUpGrid(GameObject panel){
        GridLayoutGroup grid = panel.AddComponent<GridLayoutGroup>();
        grid.cellSize = new Vector2(iconDimensions.width, iconDimensions.height);
        grid.childAlignment = TextAnchor.MiddleCenter;
        grid.spacing = iconSpacing;
    }
    void LoadIcons(int numberOfIcons, GameObject parentObject){
        for(int i = 1; i <= numberOfIcons; i++){
            currentLevelCount++;
            GameObject icon = Instantiate(levelIcon) as GameObject;
            icon.transform.SetParent(thisCanvas.transform, false);
            icon.transform.SetParent(parentObject.transform);
            icon.name = "Level " + i;
            icon.GetComponentInChildren<TextMeshProUGUI>().SetText("Level " + currentLevelCount);
        }
    }

    // Update is called once per frame
    void Update(){
        
    }
}

Source Code for PageSwiper.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

public class PageSwiper : MonoBehaviour, IDragHandler, IEndDragHandler{
    private Vector3 panelLocation;
    public float percentThreshold = 0.2f;
    public float easing = 0.5f;
    public int totalPages = 1;
    private int currentPage = 1;

    // Start is called before the first frame update
    void Start(){
        panelLocation = transform.position;
    }
    public void OnDrag(PointerEventData data){
        float difference = data.pressPosition.x - data.position.x;
        transform.position = panelLocation - new Vector3(difference, 0, 0);
    }
    public void OnEndDrag(PointerEventData data){
        float percentage = (data.pressPosition.x - data.position.x) / Screen.width;
        if(Mathf.Abs(percentage) >= percentThreshold){
            Vector3 newLocation = panelLocation;
            if(percentage > 0 && currentPage < totalPages){
                currentPage++;
                newLocation += new Vector3(-Screen.width, 0, 0);
            }else if(percentage < 0 && currentPage > 1){
                currentPage--;
                newLocation += new Vector3(Screen.width, 0, 0);
            }
            StartCoroutine(SmoothMove(transform.position, newLocation, easing));
            panelLocation = newLocation;
        }else{
            StartCoroutine(SmoothMove(transform.position, panelLocation, easing));
        }
    }
    IEnumerator SmoothMove(Vector3 startpos, Vector3 endpos, float seconds){
        float t = 0f;
        while(t <= 1.0){
            t += Time.deltaTime / seconds;
            transform.position = Vector3.Lerp(startpos, endpos, Mathf.SmoothStep(0f, 1f, t));
            yield return null;
        }
    }
}