Pop使用Flutter和StreamBuilder刷新最后一个屏幕

1 回答

• 0

  我猜你在这个例子中必须使用 StreamController 而不是 Stream .

  在您的示例中，请参阅 _streamController 次事件 .

  class ConfigCNPJPage extends StatefulWidget {
    bool voltarTela;
    ConfigCNPJPage({Key key, this.voltarTela}) : super(key: key);
  
    @override
    ConfigCNPJPageState createState() => new ConfigCNPJPageState();
  }
  
  class ConfigCNPJPageState extends State<ConfigCNPJPage>
      with SingleTickerProviderStateMixin {
      ResultConfig BD;
      List<Map> list;
      List<Widget> listArray = [];
  
      StreamController _streamController;
  
  
    Future setupList() async {
      ConfigDatabase db = ConfigDatabase();
      var banco = await db.initDB();
      list = await banco.rawQuery('SELECT * FROM Empresa');
      return list;
    }
  
  
  
      @override
      void initState() {
        super.initState();
        _streamController = new StreamController();
        setupList()?.then((o) => _streamController.add(o));
      }
  
  
  
    @override
    Widget build(BuildContext context) {
      return new StreamBuilder(
        stream: _streamController.stream,
        builder: (BuildContext context, AsyncSnapshot snapshot) {
          return snapshot.hasData?  new Scaffold(
            resizeToAvoidBottomPadding: false,
              appBar: new AppBar(
                title: new Text('Configurar Empresa'),
                actions: <Widget>[
                  new IconButton(icon: const Icon(Icons.add), onPressed: () {
                    Navigator.pushNamed(context, "NovoCNPJ").then((value) {
                        setState(() {
                          _streamController.add(value);
                        });
                    });
                  })
                ],
              ),
              body: new Column(
                children: <Widget>[
                    criarLista()
                ],
              ),
          ):new Center(child: new RefreshProgressIndicator());
        },);
    }
  }
  

  但在您的使用案例中，您是否只有一个empresa /公司或者您会有多个？

  如果你只有一个，而不是 Stream ，那么只管理一个 _empresa / _company 对象会更容易 .

  如果你希望有一个对象列表，那么我也不会使用 StreamBuilder . 我也会管理 List<Empresa> _empresas .

  class ConfigCNPJPage extends StatefulWidget {
    bool voltarTela;
    ConfigCNPJPage({Key key, this.voltarTela}) : super(key: key);
  
    @override
    ConfigCNPJPageState createState() => new ConfigCNPJPageState();
  }
  
  class ConfigCNPJPageState extends State<ConfigCNPJPage>
      with SingleTickerProviderStateMixin {
      ResultConfig BD;
      List<Map> list;
      List<Widget> listArray = [];
  
      List<Empresa> _empresas;
  
  
    Future setupList() async {
      ConfigDatabase db = ConfigDatabase();
      var banco = await db.initDB();
      list = await banco.rawQuery('SELECT * FROM Empresa');
      return list;
    }
  
    @override
    void initState() {
      super.initState();
  
      setupList()?.then((o) {
        if (_empresas == null) _empresas = new List();
  
        // if o is a list, perform a forEach on it
  
        _empresas.add(new Empresa(o))
      });
    }
  
    @override
    Widget build(BuildContext context) {
      // o melhor seria usar outra variavel pra controlar o loading,
      //   mas deve funcionar assim
      return _empresas == null
        ? new Center(child: new RefreshProgressIndicator())
        : new Scaffold(
            resizeToAvoidBottomPadding: false,
              appBar: new AppBar(
                title: new Text('Configurar Empresa'),
                actions: <Widget>[
                  new IconButton(icon: const Icon(Icons.add), onPressed: () {
                    Navigator.pushNamed(context, "NovoCNPJ").then((value) {
                        setState(() {
                          _empresas.add(new Empresa(value));
                        });
                    });
                  })
                ],
              ),
              body: new Column(
                children: <Widget>[
                    criarLista()
                ],
              ),
          );
    }
  }
  

  祝好运！

  回复于 2024-04-29T15:06:22+08:00