1-) FLUTTER - sonsuz kategori kullanımı infinite use of categories

flutter pub add stack

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:rokethizmet/ekhizmetler/statiksinif.dart';
import 'package:theme_provider/theme_provider.dart';
import 'package:stack/stack.dart' as st2;

class IlanOlusturPage extends StatefulWidget {
  const IlanOlusturPage({Key? key}) : super(key: key);

  @override
  State<IlanOlusturPage> createState() => IlanOlusturPageState();
}

class Kategori {
  late int id;
  late int masterId;
  late String kategoriAd;
}

class IlanOlusturPageState extends State<IlanOlusturPage> {

  @override
  void initState() {
    // TODO: implement initState
    super.initState();

    kategoriAdd(1, 1, "yazılım");
    kategoriAdd(2, 1, "c#");
    kategoriAdd(3, 1, "java");
    kategoriAdd(4, 1, "pyhton");
    kategoriAdd(5, 2, "mvc");
    kategoriAdd(6, 2, "first code");
    kategoriAdd(7, 3, "entity");
    kategoriAdd(8, 8, "inşaat");
    kategoriAdd(9, 8, "iç mimar");

    anaKategoriList();
  }

  st2.Stack<int> stack = st2.Stack<int>();

  void anaKategoriList() {
    stack.push(-1);
    kategoriList = kategoriListSabit
        .where((element) => element.id == element.masterId)
        .toList();
    setState(() {});
  }

  List<Kategori> kategoriListele(int id) {
    stack.push(id);

    kategoriList = kategoriListSabit
        .where((element) =>
            id == element.masterId && element.id != element.masterId)
        .toList();
    setState(() {});
    return kategoriList;
  }

  List<Kategori> kategoriList = [];

  List<Kategori> kategoriListSabit = [];

  void kategoriAdd(int id, int masterId, String ad) {
    Kategori kategori = new Kategori();
    kategori.id = id;
    kategori.masterId = masterId;
    kategori.kategoriAd = ad;
    kategoriListSabit.add(kategori);
  }

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Center(
        child: Container(
          width: kIsWeb ? 600.0 : double.infinity,
          child: Scaffold(
              appBar: AppBar(
                title: Text("İlan Oluştur"),

              ),
              body: SingleChildScrollView(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    ilanOlusturContent(),
                  ],
                ),
              ),
              floatingActionButtonLocation:
                  FloatingActionButtonLocation.centerDocked,
              floatingActionButton: Padding(
                padding: const EdgeInsets.all(8.0),
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: <Widget>[
                    FloatingActionButton(
                      onPressed: () {
                        int node = stack.pop();
                        if (node == -1) {
                          //Navigator.pop(context);
                          stack.push(-1);
                          return;
                        }
                        node = stack.pop();
                        if(node==-1){
                          anaKategoriList();
                        }else{
                          kategoriListele(node);
                        }
                      },
                      child: Icon(Icons.navigate_before, color: getTextColor()),
                      backgroundColor: getBackColor(),
                      heroTag: "btn1",
                    ),
                    // FloatingActionButton(
                    //   onPressed: () {},
                    //   child: Icon(
                    //     Icons.navigate_next,
                    //     color: getTextColor(),
                    //   ),
                    //   backgroundColor: getBackColor(),
                    //   heroTag: "btn2",
                    // )
                  ],
                ),
              )),
        ),
      ),
    );
  }

  Color getTextColor() {
    return StatikSinif.isDarkModeEnabled == true
        ? Colors.white
        : Colors.black54;
  }

  Color getBackColor() {
    return ThemeProvider.themeOf(context).data.bottomAppBarColor;
  }

  Padding ilanOlusturContent() {
    return Padding(
      padding: EdgeInsets.only(left: 10, right: 10),
      child: Material(
        elevation: 17,
        shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.all(
          Radius.circular(15.0),
        )),
        child: Padding(
          padding: EdgeInsets.all(15),
          child: buildTreeContent(),
        ),
      ),
    );
  }

  Widget buildTreeContent() {
    return Container(
      child: GridView.builder(
        controller: new ScrollController(keepScrollOffset: false),
        scrollDirection: Axis.vertical,
        shrinkWrap: true,
        itemCount: kategoriList.length,
        gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: 1,
          mainAxisExtent: 75, // yükseklik demek
        ),
        itemBuilder: (BuildContext contex, int index) {
          Kategori kategori = kategoriList[index];

          return Container(
            child: Padding(
              padding: EdgeInsets.only(top: 5),
              child: Container(
                child: MaterialButton(
                  elevation: 17,
                  shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(18.0),
                  ),
                  onPressed: () {
                    kategoriListele(kategori.id);
                  },
                  color: ThemeProvider.themeOf(context).data.bottomAppBarColor,
                  textColor: ThemeProvider.themeOf(context)
                      .data
                      .bottomSheetTheme
                      .backgroundColor,
                  child: Row(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: [
                      Text(
                        kategori.kategoriAd,
                        style: TextStyle(fontSize: 20),
                      ),
                      Icon(Icons.chevron_right_outlined)
                    ],
                  ),
                ),
              ),
            ),
          );
        },
      ),
    );
  }
}