Cocos Creator ScrollView优化

        for (let i = 0; i < 300; i++) {
            let item = this._itemPool.get()||instantiate(this.listItemPrefab)
            if (item){
                item.parent = this.listContentNd;
                item.getComponent(LIstItem)?.setData(i + "");
            }
        }

    lateUpdate() {
        if (this._isUpdating) {
            this.updateList();
        }
    }

    private updateList() {
        if (this._end == this._dataSource.length) {
            this._listItemCount = this.listContentNd.children.length;
            this._isUpdating = false;
            return;
        }

        this._start = this._end;
        //每次执行30个数据
        this._end = Math.min(this._end + 30, this._dataSource.length);
        this.renderList(this._start, this._end);
        this._isUpdating = true;
    }

    private onScrolling() {
        if (this._isUpdating || this._listItemCount == 0) return;

        this.listContentNd.children.forEach((child: Node) => {
            const visible = this.checkVisible(child);
            child.getComponent(UIOpacity)!.opacity = visible ? 255 : 0;
        });
    }

    //判断listItem是否在可视区域
    private checkVisible(listItem: Node): boolean {
        return listItem.getComponent(UITransform)!.getBoundingBoxToWorld().intersects(this._scrollViewCollisonBox);
    }