flutter - 键入'_CompactLinkedHashSet<object>' is not a subtype of type 'Widget' when using shared preferences flutter <div id="body"><p>I have shared preferences which has a collection of favorites list I read it before and take into alist so i need to display only t

问题描述

I have shared preferences which has a collection of favorites list I read it before and take into alist so i need to display only the favourite list in the favourite tab when I code it I get an error

Type '_CompactLinkedHashSet' is not a subtype of type 'Widget'

I have tried removing the { section after the !isLoaded verification then the issue is solved but I don't get what I want

This is my code

body: TabBarView(
            children: [
                 //Favourites
                 !isLoaded ? Center(child: CircularProgressIndicator()) : {
                 if(fav.length<0){
                    Center(
                
                  child: Container(
                      child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                crossAxisAlignment: CrossAxisAlignment.center,
                children: [
                  Padding(
                    padding: const EdgeInsets.only(bottom: 8.0),
                    child: Image.asset(
                      'assets/images/train.gif',
                      width: 250,
                      height: 400,
                    ),
                  ),
                  Text(
                    fav.toString(),
                    style: GoogleFonts.pacifico(
                      textStyle: TextStyle(
                          color: Colors.green, letterSpacing: .5, fontSize: 20),
                    ),
                  ),
                ],
              ))),
                 }else{
                   StreamBuilder(
                stream:
                    FirebaseFirestore.instance.collection('routes').snapshots(),
                builder: (context, snapshot) {
                  if (!snapshot.hasData)
                    return Center(child: CircularProgressIndicator());

                  return ListView(
                    children: snapshot.data.docs.map<Widget>((document) {
                      for(int b=0;b<fav.length;b++){
                      if(fav[b]==document['number'] + " " +document['name']){
                      return Center(
                        child: Container(
                          margin: const EdgeInsets.fromLTRB(20, 20, 20, 15),
                          height: 50,
                          child: RaisedButton(
                            textColor: Colors.white,
                            color: Colors.blue,
                            shape: RoundedRectangleBorder(
                              borderRadius: BorderRadius.circular(18.0),
                              side: BorderSide(color: Colors.blue),
                            ),
                            onPressed: () {
                              var id = document.id;
                              RouteNumber.route = id;
                              RouteNumber.routeName = 'Route';
                              RouteNumber.selectedRoute=document['number'] + " " +document['name'];
                              matchfav();    
                              Navigator.push(
                                  context,
                                  MaterialPageRoute(
                                      builder: (context) => LiveBus()));
                            },
                            child: Align(
                                alignment: Alignment.center,
                                child: Padding(
                                  padding: const EdgeInsets.only(top: 8.0),
                                  child: Row(
                                    children: <Widget>[
                                      Expanded(
                                        child: Marquee(
                                          text: document['number'] +
                                              " ⋮ " +
                                              document['name'],
                                          style: TextStyle(fontSize: 22),
                                          scrollAxis: Axis.horizontal,
                                          crossAxisAlignment:
                                              CrossAxisAlignment.start,
                                          blankSpace: 20.0,
                                          velocity: 50.0,
                                        ),
                                      )
                                    ],
                                  ),
                                )),
                          ),
                        ),
                      );
                    }}}
                        //

                        ).toList(),
                  );
                },
              ),
              },

flutter - 键入'_CompactLinkedHashSet

问题描述

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解决方案

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