Launcher: FlightPlann: fix ‘view route’ enable

src/GUI/FlightPlanController.cxx

@@ -32,12 +32,15 @@ const int LegAltitudeTypeRole = Qt::UserRole + 8;
 class LegsModel : public QAbstractListModel
 {
     Q_OBJECT
+
+    Q_PROPERTY(int numLegs READ numLegs NOTIFY numLegsChanged)
 public:
     void setFlightPlan(flightgear::FlightPlanRef f)
     {
         beginResetModel();
         _fp = f;
         endResetModel();
+        emit numLegsChanged();
     }
 
     int rowCount(const QModelIndex &parent) const override
@@ -132,6 +135,7 @@ public:
     {
         beginResetModel();
         endResetModel();
+        numLegsChanged();
     }
 
     QHash<int, QByteArray> roleNames() const override
@@ -152,6 +156,14 @@ public:
         return result;
     }
 
+    int numLegs() const
+    {
+        return _fp->numLegs();
+    }
+
+signals:
+    void numLegsChanged();
+
 private:
     flightgear::FlightPlanRef _fp;
 };

src/GUI/qml/FlightPlan.qml

@@ -322,6 +322,7 @@ Item {
 
                 Button {
                     text: qsTr("View route")
+                    enabled: _launcher.flightPlan.legs.numLegs > 0
                     onClicked: {
                         detailLoader.airportGuid = 0
                         detailLoader.sourceComponent = routeDetails;