detail_meals.dart

class MealsDetail extends StatefulWidget {
  final String id;
  final String category;
  final String mealThumbs;

  const MealsDetail({Key key, this.id, this.mealThumbs, this.category})
      : super(key: key);

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

class _MealsDetailState extends State<MealsDetail>
    with TickerProviderStateMixin {
  ...

  requestData() async {
    ...
  }

  updateFavorite() {
    ...
  }

  @override
  Widget build(BuildContext context) {
    SystemChrome.setSystemUIOverlayStyle(
      SystemUiOverlayStyle(
        statusBarColor: Colors.transparent,
      ),
    );

    return Scaffold(
      body: WillPopScope(
        onWillPop: () async {
          close();
        },
        child: NestedScrollView(
          controller: _scrollController,
          headerSliverBuilder: (BuildContext context, bool inner) {
            return <Widget>[
              SliverAppBar(
                leading: IconButton(
                  icon: Icon(Icons.arrow_back),
                  onPressed: close,
                ),
                backgroundColor: _isTransparent
                    ? Colors.transparent
                    : Color.fromARGB(220, 255, 255, 255),
                expandedHeight: 270,
                elevation: _elevation,
                title: Text(_appBarTittle),
                floating: false,
                pinned: true,
                flexibleSpace: FlexibleSpaceBar(
                  background: Hero(
                    tag: "${widget.mealThumbs}-${widget.category}",
                    child: CachedNetworkImage(
                      imageUrl: widget.mealThumbs,
                      width: double.infinity,
                      fit: BoxFit.cover,
                    ),
                  ),
                ),
              )
            ];
          },
          body: detail(),
        ),
      ),
    );
  }

  Widget detail() {
    if (_meals != null) {
      return Stack(
        children: <Widget>[
          ListView(
            padding: EdgeInsets.all(20),
            children: <Widget>[
              Padding(
                padding: EdgeInsets.only(top: 10.0),
                child: Text(
                  _meals.name,
                  style: TextStyle(
                    fontSize: 22,
                    fontWeight: FontWeight.bold,
                    color: Colors.black87,
                  ),
                ),
              ),
              Padding(
                padding: EdgeInsets.only(top: 10),
                child: TagsMeal(tags: _meals.tags),
              ),
              Padding(
                padding: EdgeInsets.only(top: 20.0),
                child: Text("Ingredient",
                    style: TextStyle(
                        color: Colors.black,
                        fontSize: 17,
                        fontWeight: FontWeight.bold)),
              ),
              Padding(
                padding: EdgeInsets.only(top: 10.0),
                child: CustomList(
                  data: _meals.ingredient,
                ),
              ),
              Padding(
                padding: EdgeInsets.only(top: 16.0),
                child: Text("Steps",
                    style: TextStyle(
                        color: Colors.black,
                        fontSize: 17,
                        fontWeight: FontWeight.bold)),
              ),
              Padding(
                padding: EdgeInsets.only(top: 10.0),
                child: CustomList(
                  data: _meals.steps,
                ),
              )
            ],
          ),
          Positioned(
            bottom: 16,
            right: 16,
            child: ScaleTransition(
              scale: _floatingAnimation,
              alignment: FractionalOffset.center,
              child: FloatingActionButton(
                backgroundColor: Colors.pinkAccent,
                onPressed: updateFavorite,
                child: Icon(
                  _isFavorite ? Icons.favorite : Icons.favorite_border,
                  color: Colors.white,
                ),
              ),
            ),
          )
        ],
      );
    } else {
      return Center(child: CircularProgressIndicator());
    }
  }
}