flutter - 包含最喜欢的项目的 ListView

Question

我有一个带有项目的ListView.builder，我们可以单击一颗心来添加到收藏夹。我想将添加到收藏夹的所有项目放在另一个屏幕的另一个 ListView.builder 中。我也希望通过单击心形可以抑制收藏夹 ListView 的收藏夹项目。我怎样才能做到这一点？这是我的代码:

Home_screen.dart

import 'package:flutter/material.dart';
import 'package:cached_network_image/cached_network_image.dart';
import '../recyclerview/data.dart';
import 'package:chrolix/constants.dart';
import 'package:flutter_countdown_timer/flutter_countdown_timer.dart';

int itemCount = item.length;
List<bool> selected = new List<bool>();

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  @override
  initState() {
    for (var i = 0; i < itemCount; i++) {
    selected.add(false);
    }
    super.initState();
  }
 
  Icon notFavorite = Icon(Icons.favorite_border, size: 32,);
  Icon inFavorite = Icon(Icons.favorite, size: 32,);

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body:  ListView.builder(
        scrollDirection: Axis.vertical,
        physics: BouncingScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
        itemCount: itemCount,
        itemBuilder: (BuildContext context, int index) {
      return Container(
        child: new Row(
          children: <Widget>[
            //Image
            new Container(
              margin: new EdgeInsets.only(top: 5.0, left: 0.0),
              child: new CachedNetworkImage(
                imageUrl: item[index].imageURL,
                height: MediaQuery.of(context).size.width / 3,
                width: MediaQuery.of(context).size.width / 2,
                fit: BoxFit.cover,
              ),
            ),
            new Container(
              height: MediaQuery.of(context).size.width / 3,
              width: MediaQuery.of(context).size.width / 2,
              child : new Column(
                crossAxisAlignment: CrossAxisAlignment.center,
                children: <Widget>[
            //Text
                  new Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  mainAxisSize: MainAxisSize.min,
                  children: <Widget>[
                    Spacer(),               
                   //Titre
                    Container(
                    padding: const EdgeInsets.only(top: 15.0 ),
                    child: Text(
                      item[index].title,
                      style: kItemTitle,
                      ),
                    ),
                    //Decription
                    Container(
                    padding: const EdgeInsets.only(left: 10.0, top: 15.0),
                    child:Text(
                      item[index].description,
                      style: kItemDescription,
                      ),
                    ),
                    Spacer(),
                  ],
                ),
                Container(
                padding: const EdgeInsets.only(top: 10.0),
                child: CountdownTimer(
                  daysSymbol: new Text("j "),
                  hoursSymbol: new Text(" : "),
                  minSymbol: new Text(" : "),
                  secSymbol: new Text(""),
                  endTime: item[index].countdown,
                  textStyle: TextStyle(fontSize: 28, fontWeight: FontWeight.bold),
                  onEnd: () {
              print('onEnd');
            },
                ),
                ),
                Container( 
                  padding: const EdgeInsets.only(left: 8.0, top: 8.0),
                  child: Row(
                  mainAxisAlignment: MainAxisAlignment.start,
                  crossAxisAlignment: CrossAxisAlignment.center,
                  children: <Widget>[
                    GestureDetector(
                    child: selected.elementAt(index) ? inFavorite : notFavorite,
                    onTap: () {
                      setState(() {
                        selected[index] = !selected.elementAt(index);
                      });
                    },
                ),
                ],),
              ),
              ],),
            ),        
          ],
        ),
      );
    }
    )
  );
}
}

Favorite_screen.dart

import 'package:flutter/material.dart';
import 'package:chrolix/constants.dart';
import 'package:chrolix/nav.dart';
import 'package:get/get.dart';


class Favoris extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: //Put here the LisView.builder with the favorite items
    )
  }

}

我没有看到其他可以回答我的问题。谢谢!

更新:我已经使用了提供商的软件包

Answer 1

推荐的方法是使用 provider 。这用于将变量共享到树下的多个小部件。

这需要的不仅仅是 StackOverflow 答案的编写，因此我会将您链接到 flutter 中的一篇相关文章，该文章基本上解释了您想做的所有事情: Here is is.

如果链接已损坏，您可以通过搜索“简单应用程序状态管理 flutter”找到它