如何在flutter（dart）中訪問其他類方法？

Question

我在腳手架中使用了顫振圖，並且在腳手架小部件類中有一個名為“showMyBottomSheet”的方法。 當點擊地圖並打開底部工作表時用於執行此方法的地圖。

但是現在我已將這兩個文件分開在單獨的文件中，我無法從地圖類訪問腳手架有狀態小部件中的“showMyBottomSheet”方法。

我該怎么做？ 我不應該把它們分開嗎？

我的主頁 - 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(),
        ],
      ),
    );
  }
}

地圖小部件 - 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，請注意任何以下划線開頭的方法在 Dart 中都將被視為私有方法。 看這里。

在這種情況下，您應該將該方法傳遞給子小部件並稍后調用它。 檢查這個例子：

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']),
        ],
      ),
    );
  }
}