powerfun-unity/Assets/Scripts/UI/Control/PFUIPageHelper.cs

using System;
using UnityEngine;
using UnityEngine.UI;

namespace Assets.Scripts.UI.Control
{
    [RequireComponent(typeof(ScrollRect))]
    public class PFUIPageHelper : PFUIComponentBase
    {
        public Transform content;
        public GameObject moreBtnPrefab;
        public GameObject preBtnPrefab;
        public GameObject nextBtnPrefab;
        public GameObject btnPrefab;
        public int PageIndex { get; set; }
        public int PageSize { get; set; } = 6;
        public int Total { get; set; }

        public int _pageMaxTotal = 9;

        public int _pageSpace = 4;

        private Action<int> CallBack { get; set; }
     
        public void Register(Action<int> refresh)
        {
            CallBack = refresh;
        }
        public void Build()
        {
            Utils.DestroyChildren(content);

            RenderPreviousButton();

            for (int i = 0; i < Total; i++)
            {
                if (PageIndex - 0 >= 4 && i < PageIndex)
                {
                    if (i == 0 || PageIndex -1 == i || PageIndex -2 == i)
                    {
                        RenderPageButton(i);
                    }
                    if (i == 1)
                    {
                        RenderMoreButton();
                    }
                    continue;
                }

                if (Total -PageIndex-1 >= 4 && i >= PageIndex)
                {
                    if (i == Total-1 || PageIndex == i || PageIndex + 1 == i || PageIndex + 2 == i)
                    {
                        RenderPageButton(i);
                    }
                    if (i == Total - 2)
                    {
                        RenderMoreButton();
                    }
                    continue;
                }
                RenderPageButton(i);
            }
            RenderNextButton();
        }
        private void RenderMoreButton()
        {
           var moreBtn = Instantiate(moreBtnPrefab, content);
            moreBtn.SetActive(true);
        }
        private void RenderPageButton(int pageIndex)
        {
            var btn = Instantiate(btnPrefab, content);
            var script = btn.GetComponent<PFUIPageButton>();
            script.SetPageIndex(pageIndex);

            if (pageIndex == PageIndex)
            {
                script.ShowLight();
            }
            else
            {
                script.ShowShadow();
            }

            UIManager.AddEvent(btn, UnityEngine.EventSystems.EventTriggerType.PointerClick, (e) =>
            {
                Redirect(pageIndex);
            });
        }
        private void RenderNextButton()
        {
            var nextBtn = Instantiate(nextBtnPrefab, content);
            nextBtn.SetActive(true);

            UIManager.AddEvent(nextBtn, UnityEngine.EventSystems.EventTriggerType.PointerClick, (e) =>
            {
                Next();
            });
        }
        private void RenderPreviousButton()
        {
            var preBtn = Instantiate(preBtnPrefab, content);
            preBtn.SetActive(true);

            UIManager.AddEvent(preBtn, UnityEngine.EventSystems.EventTriggerType.PointerClick, (e) =>
            {
                Previous();
            });
        }
        //上一页
        private void Previous()
        {
            var newIndex = PageIndex - 1;
            var index = newIndex < 0 ? 0 : newIndex;
            if (index != PageIndex)
            {
                PageIndex = index;
                CallBack?.Invoke(PageIndex);
                Build();
            }
        }
        //下一页
        private void Next()
        {
            var newIndex = PageIndex + 1;
            var index = newIndex >= Total ? Total-1 : newIndex;
            if (index != PageIndex)
            {
                PageIndex = index;
                CallBack?.Invoke(PageIndex);
                Build();
            }
        }
        //指定到第几页
        private void Redirect(int index)
        {
            var list = FindObjectsOfType<PFUIPageButton>();
            foreach (var item in list)
            {
                if (item.PageIndex == index)
                {
                    item.ShowLight();
                }
                else
                {
                    item.ShowShadow();
                }
            }
            PageIndex = index;
            CallBack?.Invoke(PageIndex);
            Build();
        }
    }
}