我需要将纬度和经度从rest api转换为listview

Question

我正在从 rest api 获取纬度和经度，并且每次加载列表时都必须转换为地址，但我得到 'Future' 不是'String' Flutter 类型的子类型 .我也尝试添加 FutureBuilder。如何解决这个问题我是新手。

 body: Container(
        child: Center(
          child: FutureBuilder(
            builder: (context, snapshot) {
              return ListView.builder(
                  physics: const AlwaysScrollableScrollPhysics(),
                  itemCount:
                  _getAttendanceLog == null ? 0 : _getAttendanceLog.length,
                  itemBuilder: (BuildContext context, int index) {
                    final item = _getAttendanceLog[index];
                     
                   return card(
                   child: Column(
                   children: <Widget>[
                       new Container(
                              child: Column(
                              children: <Widget>[
                              if(item.startlattitude == 'null'|| item.startlattitude == null||item.startlongitude == 'null'|| item.startlongitude == null) ...[
                              new Text("In Location : -", style: TextStyle(fontSize: SizeConfig.safeBlockHorizontal*3),)
                               ]else ...[
                               Marquee(
                               child: Text("In Location : " + getUserLocation(item.startlattitude, item.startlongitude),style: TextStyle(fontSize: SizeConfig.safeBlockHorizontal*3),),
                               directionMarguee: DirectionMarguee.oneDirection,
                               ),SizeConfig.safeBlockHorizontal*3),),
                               ]
                              ],
                            ),
                         ),
                    ])
                   )

我用过 Geocoder 也见下文 ======> getUserLocation

getUserLocation(startlat, startlong) async {

    final coordinates = new Coordinates(
        startlat, startlong);
    var addresses = await Geocoder.local.findAddressesFromCoordinates(
        coordinates);
    finalInLocation = addresses.first;
    print(' ${finalInLocation.locality}, ${finalInLocation.adminArea},${finalInLocation.subLocality}, ${finalInLocation.subAdminArea},${finalInLocation.addressLine}, ${finalInLocation.featureName},${finalInLocation.thoroughfare}, ${finalInLocation.subThoroughfare}');
    return finalInLocation;
  }

我需要这样：

Answer 1

您可以使用Geocoder包将latlng转换为地址列表

final coordinates = new Coordinates(1.10, 45.50);
addresses = await Geocoder.local.findAddressesFromCoordinates(coordinates);
first = addresses.first;
print("${first.featureName} : ${first.addressLine}");

Answer 2

您收到错误是因为您将 Future 传递给需要 String 的参数。

因为您需要等待api将lat-long转换为地址文本，所以您需要在小部件树中使用FutureBuilderitemBuilder中需要显示地址文本的位置像这样..

FutureBuilder(
            future: getUserLocation(lat, lon),
            builder: (context, snapshot) {
              if (snapshot.hasData == false) {
                return Text('loading...');
              } else {
                return Text(snapshot.data);
              }
            })

你需要让你的getUserLocation 方法返回一个Future<String> 像这样..

Future<String> getUserLocation(startlat, startlong) async {
    //other code
    await //more code;
    return yourAddressString;
  }