如何在flutter (dart)中访问其他类方法？

Question

我在脚手架中使用了颤动贴图，并且在脚手架窗口小部件类中有一个名为"showMyBottomSheet“的方法。当点击地图并打开底部工作表时用于执行此方法的地图。

但是现在我已经将这两个文件分离到单独的文件中，我不能从map类访问scaffold有状态小部件中的"showMyBottomSheet“方法。

我该怎么做呢？我是不是应该把他们分开？

我的主页- home.dart

class MyHomePage extends StatefulWidget {
  static const String route = '/';

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  static const String route = '/';

  // Bottom sheet
  final _scaffoldKey = new GlobalKey<ScaffoldState>();

  dynamic showMyBottomSheet(LatLng latlang) {
    _scaffoldKey.currentState.showBottomSheet((context) {
      return new CustomBottomSheet();
    });
  }

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      key: _scaffoldKey,
      drawer: buildDrawer(context, route),
      body: new Column(
        children: [
          new CustomMap(),
        ],
      ),
    );
  }
}

地图小部件- flutterMap.dart

class Cuenter code herestomMap extends StatefulWidget {
  @override
  _CustomMapState createState() => new _CustomMapState();
}

class _CustomMapState extends State<CustomMap> {
  var markers = <Marker>[];

  @override
  Widget build(BuildContext context) {
    return new Flexible(
      child: new FlutterMap(
        options: new MapOptions(
            center: new LatLng(51.25, 30.5),
            zoom: 15.0,
            onTap: // I want to call showMyBottomSheet method (from home page) here
        ),
        layers: [
          new TileLayerOptions(
              urlTemplate:
              "https://maps.wikimedia.org/osm-intl/{z}/{x}/{y}.png",
              subdomains: ['a', 'b', 'c']),
        ],
      ),
    );
  }
}

Answer 1

首先，请注意，任何以下划线开头的方法在Dart中都将被视为私有方法。look here。

在这种情况下，您应该将方法传递给子小部件，并在以后调用它。检查此示例：

class MyHomePage extends StatefulWidget {
  static const String route = '/';

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  static const String route = '/';

  // Bottom sheet
  final _scaffoldKey = new GlobalKey<ScaffoldState>();

  dynamic showMyBottomSheet(LatLng latlang) {
    _scaffoldKey.currentState.showBottomSheet((context) {
      return new CustomBottomSheet();
    });
  }

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      key: _scaffoldKey,
      drawer: buildDrawer(context, route),
      body: new Column(
        children: [
          new CustomMap(onMapTap: showMyBottomSheet),
        ],
      ),
    );
  }
}

在flutterMap.dart中：

class CustomMap extends StatefulWidget {
  Function onMapTap;
  CustomMap({this.onMapTap});

  @override
  _CustomMapState createState() => new _CustomMapState();
}

class _CustomMapState extends State<CustomMap> {
  var markers = <Marker>[];

  @override
  Widget build(BuildContext context) {
    return new Flexible(
      child: new FlutterMap(
        options: new MapOptions(
            center: new LatLng(51.25, 30.5),
            zoom: 15.0,
            onTap: (){
              widget.onMapTap(LatLng(34.12312,56.1323));
            }
        ),
        layers: [
          new TileLayerOptions(
              urlTemplate:
              "https://maps.wikimedia.org/osm-intl/{z}/{x}/{y}.png",
              subdomains: ['a', 'b', 'c']),
        ],
      ),
    );
  }
}