Question

我在iOS应用中实现了Here Maps导航SDK。当我在开始导航之前计算路线时，我将路线保存在实例变量中：self.route。

// Trigger the route calculation
[self.router
    calculateRouteWithStops:stops
                routingMode:routingMode
            completionBlock:^(NMARouteResult* routeResult, NMARoutingError error) {
              if (error) {
                  reject(@"route_calculation_error", [NSString stringWithFormat:@"Error %d when calculating route", (int)error], nil);
                  return;
              }
              if (!routeResult || routeResult.routes.count == 0) {
                  reject(@"route_calculation_no_result", @"Error when calculation route: no result", nil);
                  return;
              }

              // Let's add the 1st result onto the map
              self.route = routeResult.routes[0];
              self.mapRoute = [NMAMapRoute mapRouteWithRoute:self.route];
              [self.mapView addMapObject:self.mapRoute];

              [self zoomToRoute];

              [self updateNavigationMode:kNavigationModeRoute];
              resolve(@{
                  @"length" : @(self.route.length),
                  @"duration" : @(self.route.tta.duration),
              });
            }];

然后，当我调用停止导航的功能时，路线将从地图中删除，self.route为零。我想在地图上保留路线并返回行程视图。

[self zoomToRoute];
[self.navigationManager stop]; // after this call, self.route == nil
[self updateNavigationMode:kNavigationModeRoute];

这是我提出的解决方案，但我宁愿不重新创建mapRoute，感觉很讨厌......

[self zoomToRoute];
// for some reason navigationManger#stop releases self.route and removes
// the mapRoute from the map so we create it again
NMARoute* route = self.route;
[self.navigationManager stop];
self.route = route;
self.mapRoute = [NMAMapRoute mapRouteWithRoute:self.route];
[self.mapView addMapObject:self.mapRoute];
[self updateNavigationMode:kNavigationModeRoute];

Answer 1

NMARoute的所有权独立于导航和所有其他环境。只要您的self.route保留了强引用，只要您的应用程序需要它，您就可以重复使用NMARoute对象。

调用navigationManager.stop后如何保留NMARoute引用？

1 个答案: