demo/xinhuaribao/lib/ui/news/main_news_page.dart

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:news_app/ui/news/news_child_main_page.dart';
import 'package:news_app/ui/search/search_bar_widget.dart';

import '../../constant/color_res.dart';
import '../../gen/assets.gen.dart';
import '../../model/news_category_model.dart';
import '../../provider/news_category_provider.dart';

/// @author: bo.zeng
/// @email: cnhbwds@gmail.com
/// @date: 2025 2025/4/9 16:00
/// @description:
class MainNewsPage extends ConsumerStatefulWidget {
  const MainNewsPage({super.key});

  @override
  ConsumerState<MainNewsPage> createState() => _MainNewsPageState();
}

final newsCategoryProvider =
    NotifierProvider<NewsCategoryProvider, List<NewsCategoryModel>>(() {
      return NewsCategoryProvider();
    });
final tabIndexProvider = StateProvider<int>((ref) => 0);

final List<Color> _startColorList = [
  color343090,
  color5F59F7,
  color6592FD,
  color8C61FF,
  color44C2FD,
  color5F59F7,
];

final List<Color> _middleColorList = [
  color343090,
  color5F59F7,
  color6592FD,
  color8C61FF,
  color44C2FD,
  color6379FB,
];

class _MainNewsPageState extends ConsumerState<MainNewsPage>
    with AutomaticKeepAliveClientMixin, SingleTickerProviderStateMixin {
  TabController? _tabController;

  @override
  void initState() {
    super.initState();
    ref.read(newsCategoryProvider.notifier).fetchNewsCategoryList();
  }

  @override
  void dispose() {
    super.dispose();
    _tabController?.dispose();
  }

  @override
  Widget build(BuildContext context) {
    super.build(context);
    final result = ref.watch(newsCategoryProvider);
    var categoryList = result;
    if (result.length > 6) {
      categoryList = result.take(6).toList();
    }
    final tabIndex = ref.watch(tabIndexProvider);
    if (categoryList.isEmpty) {
      return const SizedBox.shrink();
    }
    // 初始化 tabController（只初始化一次）
    if (_tabController == null) {
      _tabController = TabController(length: categoryList.length, vsync: this);
      _tabController?.addListener(() {
        ref.read(tabIndexProvider.notifier).state = _tabController?.index ?? 0;
      });
    }
    return Scaffold(
      appBar: AppBar(
        backgroundColor: _startColorList[tabIndex],
        systemOverlayStyle: SystemUiOverlayStyle(
          statusBarColor: _middleColorList[tabIndex],
          statusBarIconBrightness: Brightness.light, // 状态栏图标颜色
        ),
        title: Row(
          spacing: 10.w,
          children: [
            Image.asset(Assets.images.logo.path, width: 70.w),
            Expanded(child: SearchBarWidget(tabIndex: 0)),
          ],
        ),
        bottom: TabBar(
          controller: _tabController,
          tabAlignment: TabAlignment.center,
          isScrollable: true,
          indicatorColor: Colors.white,
          dividerHeight: 0,
          labelColor: Colors.white,
          // 选中标签颜色
          unselectedLabelColor: Colors.white,
          // 未选中标签颜色
          labelStyle: TextStyle(
            fontWeight: FontWeight.bold, // 选中标签加粗
            fontSize: 16.0.sp,
          ),
          unselectedLabelStyle: TextStyle(
            fontWeight: FontWeight.normal, // 未选中标签不加粗
            fontSize: 16.0.sp,
          ),
          tabs: categoryList.map((item) => Tab(text: item.name)).toList(),
        ),
      ),
      body: Stack(
        children: [
          Positioned(
            child: Container(
              height: 100.h,
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  colors: [
                    _startColorList[tabIndex],
                    _middleColorList[tabIndex],
                    Colors.white,
                  ],
                  begin: Alignment.topCenter,
                  end: Alignment.bottomCenter,
                ),
              ),
            ),
          ),

          TabBarView(
            controller: _tabController,
            children: getListPage(categoryList),
          ),
        ],
      ),
    );
  }

  List<Widget> getListPage(List<NewsCategoryModel> items) {
    List<Widget> list = [];
    items.asMap().entries.forEach((element) {
      list.add(NewsChildMainPage(tabIndex: element.key));
    });
    return list;
  }

  @override
  bool get wantKeepAlive => true;
}