詳細說明
QGeoRoutingManager類提供對地理路由操作的支援。
computeRoute（）和updateRoute（）方法函式QGeoRouteReply物件，它們管理這些操作並報告這些操作的結果以及可能發生的任何錯誤。
validateRoute（）函式用於查詢遵循一組路點並匹配其他各種條件的一條或多條路線。 QGeoRouteRequest類用於指定此資訊。
如果supportsRou​​teUpdates（）返回true，則QGeoRoutingManager支援基於位置更新來更新路線資訊。這將導致旅行時間和距離估計值得到更新，並且已經遍歷的所有QGeoRouteSegments將從路線中刪除。

class MyRouteHandler : public QObject
  {
      Q_OBJECT
  public:
      MyRouteHandler(QGeoRoutingManager *routingManager,
                     const QGeoCoordinate &
 
origin,
                     const QGeoCoordinate &destination) {

          QGeoRouteRequest request(origin, destination);

          // The request defaults to the fastest route by car, which is
          // equivalent to:
          // request.setTravelMode(QGeoRouteRequest::CarTravel);
          // request.setRouteOptimization(
 
QGeoRouteRequest::FastestRoute);

          request.setAvoidFeatureTypes(QGeoRouteRequest::AvoidTolls);
          request.setAvoidFeatureTypes(QGeoRouteRequest::AvoidMotorPoolLanes);

          QGeoRouteRequest::AvoidFeaturesTypes avoidableFeatures = routingManager->supportedAvoidFeatureTypes();

          if (!(avoidableFeatures & request.avoidFeatureTypes())) {
              // ... inform the user that the routing manager does not
              // provide support for avoiding tolls and/or motor pool lanes ...
              return;
          }

          QGeoRouteReply *reply = routingManager->calculateRoute(request);

          if (reply->isFinished()) {
              if (reply->error() == QGeoRouteReply::NoError) {
                  routeCalculated(reply);
              } else {
                  routeError(reply, reply->error(), reply->errorString());
              }
              return;
          }

          connect(routingManager,
                  SIGNAL(finished(QGeoRouteReply*)),
                  this,
                  SLOT(routeCalculated(QGeoRouteReply*)));

          connect(routingManager,
                  SIGNAL(error(QGeoRouteReply*,QGeoRouteReply::Error,QString)),
                  this,
                  SLOT(routeError(QGeoRouteReply*,QGeoRouteReply::Error,QString)));
      }

  private slots:
      void routeCalculated(QGeoRouteReply *reply)
      {
          // A route request can ask for several alternative routes ...
          if (reply->routes().size() != 0) {

              // ... but by default it will only get a single route
              QGeoRoute route = reply->routes().at(0);

              //... now we have to make use of the route ...
          }

          reply->deleteLater();
      }

      void routeError(QGeoRouteReply *reply, QGeoRouteReply:Error error, const QString &errorString)
      {
          // ... inform the user that an error has occurred ...
          reply->deleteLater();
      }
  };