Flutter:如何在切换页面时保持Google地图折线的状态

dependencies:
  google_maps_flutter: ^2.0.10

import 'package:google_maps_flutter/google_maps_flutter.dart';

GoogleMap(
  initialCameraPosition: CameraPosition(
    target: LatLng(37.7749, -122.4194), // 设置地图初始位置
    zoom: 12.0, // 设置初始缩放级别
  ),
  polylines: {
    Polyline(
      polylineId: PolylineId('polyline_1'), // 设置折线的唯一ID
      points: [
        LatLng(37.7749, -122.4194), // 折线点1
        LatLng(37.7749, -122.4294), // 折线点2
        LatLng(37.7849, -122.4294), // 折线点3
      ],
      color: Colors.blue, // 设置折线颜色
      width: 5, // 设置折线宽度
    ),
  },
)

List<Polyline> polylines = [
  Polyline(
    polylineId: PolylineId('polyline_1'),
    points: [
      LatLng(37.7749, -122.4194),
      LatLng(37.7749, -122.4294),
      LatLng(37.7849, -122.4294),
    ],
    color: Colors.blue,
    width: 5,
  ),
];

GoogleMap(
  initialCameraPosition: CameraPosition(
    target: LatLng(37.7749, -122.4194),
    zoom: 12.0,
  ),
  polylines: Set<Polyline>.from(polylines),
)