Flutter 单击按钮时更改 state

Question

大家好，昨天我遇到了一个问题，如何通过单击按钮将一个有状态小部件的 state 从另一个有状态小部件更改为新的 API 响应，并应将新数据放入未来的构建器中，以便在单击按钮时重新渲染,（因为我的一切都从 API 工作并正确构建，但只有在更改为另一个小部件并再次返回之前）
我看到了关于 Bloc 和 Stream 模式（来自 fireship.io），但它给了我 null 数据，这是我的代码：

class HomeState extends State<Home>
{
  Future<List<String>> futureCurrency;
  int _currentIndex = 0;
  final List<Widget> _children = [
    Credit(),
    Deposit(),
    Currency(),
  ];
  Map<String, bool> values = {
    'Микрозайм': true,
    'Потребительский': false,
    'Автокредит': false,
    'Овердрафт': false,
    'Ипотечный': false,
    'Образовательный': true,
    'Традиционный вклад': false,
    'Онлайн вклад': false
  };
   Widget creditType_tiles(BuildContext context){
    return Column(children: values.keys.map((val){
      return new CheckboxListTile(
        title: new Text(val),
        value: values[val],
        controlAffinity: ListTileControlAffinity.leading,
        onChanged: (bool value){
          setState((){values[val] = value; });
        },
      );
    }).toList());
  }
    Widget currency_data(BuildContext context){
    try{
      return Column(mainAxisSize: MainAxisSize.min,children: [
          RadioListTile(
            groupValue: widget.currency_type,
            onChanged: (val){
              setState((){widget.currency_type= val; });
              print(val);
            },
            title: Text(currencies[0]),
            value: 0
          ), RadioListTile(
            groupValue: widget.currency_type,
            onChanged: (val){
              setState((){widget.currency_type = val; });
            },
            title: Text(currencies[1]),
            value: 1
          ), RadioListTile(
            groupValue: widget.currency_type,
            onChanged: (val){
              setState((){ widget.currency_type = val; });
            },
            title: Text(currencies[2]),
            value: 2
          ),
        ]);
    }catch(Exception ){

    }
  }
   Widget currency_tile(BuildContext context,AsyncSnapshot<List<String>> snap,String names,int i){
    return Row(children: <Widget>[
        SvgPicture.asset(assets[i],width: 30.0,height: 30.0),
        Padding(child:new Text("${names} ${snap.data[i]}",style: TextStyle(fontSize: 14.0,color: Colors.black)),padding: EdgeInsets.only(left: 10.0))
    ]);

  }
  Widget percent_data(BuildContext context){
    try{
      return Column(mainAxisSize: MainAxisSize.min,children: [
          RadioListTile(
            groupValue: widget.isAscending,
            onChanged: (val){
              setState((){ widget.isAscending = val; });
              print('${widget.isAscending} Min');
            },
            title: Text("Минимальная"),
            value: 0
          ),
          RadioListTile(
            groupValue: widget.isAscending,
            onChanged: (val){
              setState((){widget.isAscending = val; });
              print('${widget.isAscending} Max');
            },
            title: Text("Максимальная"),
            value: 1
          ),
        ]);
    }catch(Exception ){

    }
  }
  Future _apiCall(int isAsc,int currency_type) async {
    switch(_currentIndex){
      case 0: await setState( () { Home.credits_show = _apiCallCredit(isAsc,currency_type);});  break;
      case 1: await setState( () { Home.deposits_show = _apiCallDeposit(isAsc,currency_type);});  break;
      default: break;
    }
  }
  Future<List<Credit_Model>> _apiCallCredit(int isAsc,int currency_type) async {
    return await Webservice().loadCredit(Credit_Model.getAll,isAsc,currency_type);
  }
  Future<List<Deposit_Model>> _apiCallDeposit(int isAscending,int currency_type) async {
    return await Webservice().loadDeposit(Deposit_Model.getAll,isAscending,currency_type);
  }

  @override
  void initState(){
    super.initState();
    futureCurrency = getValues();
    Home.credits_show = _apiCallCredit(0, 1);
    Home.deposits_show  = _apiCallDeposit(0, 1);
  }
  @override
  Widget build(BuildContext context){
    // final String menuSvg = "https://image.flaticon.com/icons/svg/149/149271.svg";  // alternative way from network
    Widget home;
    try{
      home = Scaffold(
        key: _scaffoldkey,
        appBar: new AppBar(
        leading: Badge(
          padding: EdgeInsets.all(2.0),
          animationDuration: Duration(milliseconds: 2500),
          position: BadgePosition(bottom: 25.0,left: 30.0),
          badgeContent: Text('10',style: TextStyle(color: Colors.white)),
          badgeColor: Colors.red,
          child: Align(child:IconButton(icon: Icon(Icons.menu),onPressed: (){ _scaffoldkey.currentState.openDrawer();}),alignment: Alignment.center),
        ),
        iconTheme: new IconThemeData(color: Color.fromARGB(255,83,83,83)),
        backgroundColor: Color.fromARGB(255,255,206,0),
        title: Text("Кредит",style:TextStyle(color: Color.fromARGB(255,83,83,83))),
        centerTitle: true,
        actions: <Widget>[
          IconButton(icon: SvgPicture.asset("assets/images/controls.svg",width: 20.0,height:20.0,color:Color.fromARGB(255,83,83,83)),onPressed: () => _scaffoldkey.currentState.openEndDrawer() )
        ],
      ),
        drawer: new Drawer(
        elevation: 20.0,
       child: Container(
         height: MediaQuery.of(context).size.height,
         child:Column(
         children: <Widget>[
          DrawerHeader(
          child: Container(
            child: Image.asset("assets/images/logo.jpg"),
            width: double.infinity,
            padding: EdgeInsets.only(bottom: 10.0),
            height: double.infinity,
          )
        ),
          Column(children: tiles(context)),
          Expanded(
            flex: 1,
            child:Wrap(
            crossAxisAlignment: WrapCrossAlignment.center,
            alignment: WrapAlignment.end,
            direction: Axis.vertical, children: [ 
            Text("Мы в социальный сетях"),
             new Wrap(
              children: [
                FlatButton(
                child: Icon(Icons.photo_camera),
                onPressed: () {},
              ),
              FlatButton(
                child: Icon(Icons.flight),
                onPressed: () { },
              )
              ]
             )
            ]),
          )
        ])
       )),
      endDrawer: Drawer(
        elevation: 20.0,
        child: Container(
        color: Colors.white,
        child:ListView(
         children: <Widget>[
          DrawerHeader(
          padding: EdgeInsets.only(bottom: 20.0,left: 15.0),
          margin: EdgeInsets.only(bottom: 50.0),
          decoration: BoxDecoration(
            color: Colors.white
          ),
          child: 
          Column(
            mainAxisSize: MainAxisSize.max,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text("Курс валют ЦБ",style: TextStyle(color: Colors.black,fontSize: 18.0)),
              SizedBox(height: 10.0),
              Expanded(child:FutureBuilder(
                future: futureCurrency,
                builder: (BuildContext context,AsyncSnapshot<List<String>>snap){
                  try{
                    if(snap.connectionState == ConnectionState.done){
                    return ListView.builder(

                      cacheExtent: 100.0,
                      scrollDirection: Axis.vertical,
                      itemCount: snap.data != null ? snap.data.length : 1,
                      itemBuilder: (context,i){
                        return currency_tile(context, snap, names[i],i);
                      }
                    );
                    }else if(snap.connectionState == ConnectionState.none){
                      return new Center(child: new CircularProgressIndicator(backgroundColor: Color.fromARGB(255, 255, 206, 0)));
                    }
                  }catch(Exception){
                    return new Center(child:CircularProgressIndicator(backgroundColor: Color.fromARGB(255, 255, 206, 0)));
                  }
                },
              )
              ),
            ],
          ),

        ),
        SizedBox(height: 10.0),
          Padding(child:Text(
            "Процентная ставка",
            style: TextStyle(
              fontSize: 16.0,
              color: Colors.black,
              fontWeight: FontWeight.bold
            )
          ),
          padding: EdgeInsets.only(left: 15.0),
          ),
          percent_data(context),
          SizedBox(height: 20.0),
          Padding(child:Text(
            "Вид валюты",
            style: TextStyle(
              fontSize: 16.0,
              color: Colors.black,
              fontWeight: FontWeight.bold
            )

          ),
          padding: EdgeInsets.only(left: 15.0),
        ),
          currency_data(context), 
          SizedBox(height: 20.0),       
          Padding(child:Text(
            "Вид Кредита",
            style: TextStyle(
              fontSize: 16.0,
              color: Colors.black,
              fontWeight: FontWeight.bold
            )
          ),
          padding: EdgeInsets.only(left: 15.0),
          ),
          creditType_tiles(context),
          SizedBox(height: 10.0),
          Padding(child:Text(
            "Срок вклада",
            style: TextStyle(
              fontSize: 16.0,
              color: Colors.black,
              fontWeight: FontWeight.bold
            )
          ),
          padding: EdgeInsets.only(left: 15.0,bottom: 10.0),
          ) ,
          //slider_range(context),
        Align(alignment: Alignment.centerLeft,
        child: Padding(child:new RaisedButton(
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(5.0)),
          color: Color.fromARGB(255, 85, 174,36),
          child: new Text('Применить',
            style: TextStyle(
              color: Colors.white
            )
          ),onPressed: () async {
            _apiCall(widget.isAscending, widget.currency_type);
          }
        ),
        padding: EdgeInsets.only(left:25.0),
        )
        ),
        ]
      )
      )
      ),
        bottomNavigationBar: new BottomNavigationBar(
        backgroundColor: Color.fromARGB(255, 75, 75, 75),
        onTap: onTabTapped,
        selectedItemColor: Colors.yellow[600],
        unselectedItemColor: Colors.grey[400],
        currentIndex: _currentIndex,
        items: [
          BottomNavigationBarItem(
            icon: new SvgPicture.asset("assets/images/credit-card1.svg",color: _currentIndex == 0 ? Color.fromARGB(255, 255, 206, 0) : Color.fromARGB(255, 177, 177, 177)),
            title: new Text("Кредит")
          ),
          BottomNavigationBarItem(
            icon: new SvgPicture.asset("assets/images/deposit active.svg",color: _currentIndex == 1 ? Color.fromARGB(255, 255, 206, 0) : Color.fromARGB(255, 177, 177, 177)),
            title: new Text("Вклад")
          ),
          BottomNavigationBarItem(
            icon: new SvgPicture.asset("assets/images/dollar-coin-stack.svg",color: _currentIndex == 2 ? Color.fromARGB(255, 255, 206, 0) : Color.fromARGB(255, 177, 177, 177)),
            title: new Text("Курс валют")
          )
        ]
      ),
      body: _children[_currentIndex],
    );
    return home;
    }catch(Exception ){

    }  
  }
}