flutter - Future Builder 无法使用颤振的 Geolocator

Question

我对颤振有点陌生，我是第一次使用 Geolocator 插件。我正在尝试拥有一个 FutureBuilder，它可以在构建时找到用户所在的城市，但它永远不会离开加载屏幕

这是我当前的代码：

 class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {

String currentTown;


  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: _getTown(),
        builder: (context, snap) {
        if(snap.connectionState == ConnectionState.waiting) {
          return Loading();
        } else {
          return Center(
            child: Text(
              currentTown ?? null,
              style: TextStyle(
                color: Colors.white
              ),
            ),
          );
        }
        }
    );
  }

  Future _getTown() async {
    print('get Town');
    Position pos = await Geolocator.getCurrentPosition(desiredAccuracy: LocationAccuracy.high);
    final coordinates = Coordinates(pos.latitude, pos.longitude);
    var address = await Geocoder.local.findAddressesFromCoordinates(coordinates);
    print(address.first.locality);
    setState(() {
      currentTown = address.first.locality;
    });
  }

}

pubspec.yaml：

dependencies:
  geolocator: ^7.0.1
  geocoder: ^0.2.1

我不完全确定我做错了什么。我尝试让未来返回字符串值，但它仍然不会从加载屏幕更改。即使我使用 ConnectionState 它仍然无法正常工作

标签： flutterdartgeolocationfutureflutter-futurebuilder

Answer 1

你需要退回一些东西试试这个

Future _getTown() async {
       return address.first.locality;
      }

还修改您的构建器

 builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.done) {
              if (snapshot.hasData) {
             print(snapshot.data);
              }
     else{return loadingWidget();}