1-) FLUTTER - SliverList SliverAppBar vs kullanımı

SONRADAN EKLEDİM GÜZEL GİBİ bunuda kullan -> https://www.roketnot.com/not/1435-basit-hero-animations-kullanimi

import 'package:flutter/material.dart';

import '../anasayfa_model.dart';

class GeciciPage extends StatefulWidget {
  AnasayfaModel currentModel;

  GeciciPage({required this.currentModel, Key? key}) : super(key: key);

  @override
  _MemnuniyetMainPageState createState() => _MemnuniyetMainPageState();
}

class _MemnuniyetMainPageState extends State<GeciciPage> {
  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Container(
        child: CustomScrollView(
          slivers: <Widget>[
            SliverAppBar(
              expandedHeight: 100.0,
              pinned: true,
              flexibleSpace: FlexibleSpaceBar(
                title: Column(
                  mainAxisAlignment: MainAxisAlignment.end,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children:  <Widget>[
                    Text(widget.currentModel.ad,style: TextStyle(fontSize: 13)),
                    Text('', style: TextStyle(fontSize: 10)),
                  ],
                ),
                background: Hero(
                  tag: 'location-img-${widget.currentModel.logo}',
                  child: Image.asset(
                    "assets/images/${widget.currentModel.logo}.png",
                    height: 70,
                    alignment: Alignment.centerRight,
                  ),
                ),
              ),
            ),
            SliverList(
              delegate: SliverChildBuilderDelegate(
                    (_, int index) {
                  return Container();
                },
                childCount: 1,
              ),
            ),
          ],
        ),
      ),
    );
  }
}

DİĞER

body: Container(
  child: CustomScrollView(
    slivers: <Widget>[
      SliverAppBar(
        expandedHeight: 250.0,
        pinned: true,
        flexibleSpace: FlexibleSpaceBar(
          title: Text('Goa', textScaleFactor: 1),
          background: Image.asset(
            'assets/images/rmos.png',
            fit: BoxFit.fill,
          ),
        ),
      ),
      SliverList(
        delegate: SliverChildBuilderDelegate(
          (_, int index) {
            return ListTile(
              leading: Container(
                  padding: EdgeInsets.all(8),
                  width: 100,
                  child: Placeholder()),
              title: Text('Place ${index + 1}', textScaleFactor: 2),
            );
          },
          childCount: 20,
        ),
      ),
    ],
  ),
),

kaynak : https://blog.logrocket.com/how-to-add-sliverappbar-to-your-flutter-app/

SliverGrid.count u da kullabilirsin

*******************DİĞERİ BU DAHA GÜZEL ***************************

pubspec.yaml' a resmin rengine göre appbarın rengini yapar ekle -> palette_generator: 0.3.3

import 'package:flutter/material.dart';
import 'package:palette_generator/palette_generator.dart';

import '../model/burc.dart';

class BurcDetay extends StatefulWidget {
  final Burc secilenBurc;
  const BurcDetay({required this.secilenBurc, Key? key}) : super(key: key);

  @override
  _BurcDetayState createState() => _BurcDetayState();
}

class _BurcDetayState extends State<BurcDetay> {
  Color appbarRengi = Colors.transparent;
  late PaletteGenerator _generator;

  @override
  void initState() {
    super.initState();

    print('init state çalıstıktan sonra');
    WidgetsBinding.instance!.addPostFrameCallback((_) => appbarRenginiBul());
    // _generator = PaletteGenerator.fromImageProvider(AssetImage(assetName));
  }

  @override
  Widget build(BuildContext context) {
    print('build çalıstı');
    return Scaffold(
        body: CustomScrollView(
      slivers: [
        SliverAppBar(
          expandedHeight: 250,
          pinned: true,
          backgroundColor: appbarRengi,
          flexibleSpace: FlexibleSpaceBar(
            title: Text(widget.secilenBurc.burcAdi + " Burcu ve Özellikleri"),
            centerTitle: true,
            background: Image.asset(
              'images/' + widget.secilenBurc.burcBuyukResim,
              fit: BoxFit.cover,
            ),
          ),
        ),
        SliverToBoxAdapter(
          child: Container(
            margin: EdgeInsets.all(16),
            padding: EdgeInsets.all(8),
            child: SingleChildScrollView(
              child: Text(
                widget.secilenBurc.burcDetayi,
                style: Theme.of(context).textTheme.subtitle1,
              ),
            ),
          ),
        ),
      ],
    ));
  }

  void appbarRenginiBul() async {
    print('build bitti baskın renk bulunacak');
    _generator = await PaletteGenerator.fromImageProvider(
        AssetImage('assets/images/${widget.secilenBurc.burcBuyukResim}'));
    appbarRengi = _generator.vibrantColor!.color;
     print('baskın renk bulundu build metotu tekrar calıstırılacak');
    setState(() {});
    print(appbarRengi);
  }
}

****AÇIKLAMA****

Aşağıdaki kod initstate çalıştıktan yani build edildikten sonra çalışan kod demek

WidgetsBinding.instance!.addPostFrameCallback((_) => appbarRenginiBul());

@override
void initState() {
  super.initState();

  print('init state çalıstı');
  WidgetsBinding.instance!.addPostFrameCallback((_) => appbarRenginiBul());
  // _generator = PaletteGenerator.fromImageProvider(AssetImage(assetName));
}