一个小缺陷

import 'package:flutter/material.dart';

import 'package:amap_flutter_map/amap_flutter_map.dart';
import 'package:amap_flutter_base/amap_flutter_base.dart';

class RunPage extends StatefulWidget {
  RunPage({Key key}) : super(key: key);

  @override
  _RunPageState createState() => _RunPageState();
}

class _RunPageState extends State<RunPage> {
  List<Widget> _approvalNumberWidget = <Widget>[];

  static const AMapApiKey amapApiKeys = AMapApiKey(
      androidKey: 'f80b827969ecf361f33aee48accfa025',
      iosKey: '96be023e56b7ff4f1bc0cd67ac8f5a83');

  @override
  Widget build(BuildContext context) {
    final AMapWidget map = AMapWidget(
      mapType: MapType.satellite,
      apiKey: amapApiKeys,
      onMapCreated: onMapCreated,
      zoomGesturesEnabled: true,
      myLocationStyleOptions: MyLocationStyleOptions(
        true,
        circleFillColor: Colors.lightBlue,
        circleStrokeColor: Colors.blue,
        circleStrokeWidth: 1,
      ),
    );

    return Scaffold(
      body: ConstrainedBox(
        constraints: BoxConstraints.expand(),
        child: Stack(
          alignment: Alignment.center,
          children: [
            GestureDetector(
              child: Container(
//              height: MediaQuery.of(context).size.height,
//              width: MediaQuery.of(context).size.width,
                child: map,
              ),
              onScaleUpdate: (ScaleUpdateDetails details) {
                print('查看缩放数值：');
                print(details.scale);
                print(details.horizontalScale);
                print(details.verticalScale);
              },
            ),
          ],
        ),
      ),
    );
  }

  AMapController _mapController;
  void onMapCreated(AMapController controller) {
    setState(() {
      _mapController = controller;
      getApprovalNumber();
    });
  }

  /// 获取审图号
  void getApprovalNumber() async {
    //普通地图审图号
    String mapContentApprovalNumber =
    (await _mapController.getMapContentApprovalNumber());
    //卫星地图审图号
    String satelliteImageApprovalNumber =
    (await _mapController.getSatelliteImageApprovalNumber());
    setState(() {
      _approvalNumberWidget.add(Text(mapContentApprovalNumber));
      _approvalNumberWidget.add(Text(satelliteImageApprovalNumber));
    });
    print('地图审图号（普通地图）: $mapContentApprovalNumber');
    print('地图审图号（卫星地图): $satelliteImageApprovalNumber');
  }
}