Fixed crash when switching to the Flight Modes panel.

src/AutoPilotPlugins/PX4/FlightModesComponent.cc

@@ -107,6 +107,8 @@ QString FlightModesComponent::prerequisiteSetup(void) const
             return plugin->airframeComponent()->name();
         } else if (!plugin->radioComponent()->setupComplete()) {
             return plugin->radioComponent()->name();
+        } else if (!plugin->sensorsComponent()->setupComplete()) {
+            return plugin->sensorsComponent()->name();
         }
     }
 

src/AutoPilotPlugins/PX4/PX4AutoPilotPlugin.cc

@@ -106,14 +106,14 @@ const QVariantList& PX4AutoPilotPlugin::vehicleComponents(void)
             _radioComponent->setupTriggerSignals();
             _components.append(QVariant::fromValue((VehicleComponent*)_radioComponent));
 
-            _flightModesComponent = new FlightModesComponent(_vehicle, this);
-            _flightModesComponent->setupTriggerSignals();
-            _components.append(QVariant::fromValue((VehicleComponent*)_flightModesComponent));
-            
             _sensorsComponent = new SensorsComponent(_vehicle, this);
             _sensorsComponent->setupTriggerSignals();
             _components.append(QVariant::fromValue((VehicleComponent*)_sensorsComponent));
 
+            _flightModesComponent = new FlightModesComponent(_vehicle, this);
+            _flightModesComponent->setupTriggerSignals();
+            _components.append(QVariant::fromValue((VehicleComponent*)_flightModesComponent));
+
             _powerComponent = new PowerComponent(_vehicle, this);
             _powerComponent->setupTriggerSignals();
             _components.append(QVariant::fromValue((VehicleComponent*)_powerComponent));

src/AutoPilotPlugins/PX4/PX4SimpleFlightModesController.cc

@@ -53,9 +53,21 @@ void PX4SimpleFlightModesController::_rcChannelsChanged(int channelCount, int pw
     }
     emit rcChannelValuesChanged();
 
-    int flightModeChannel = getParameterFact(-1, "RC_MAP_FLTMODE")->rawValue().toInt() - 1;
+    Fact* pFact = getParameterFact(-1, "RC_MAP_FLTMODE");
+    if(!pFact) {
+        qCritical() << "RC_MAP_FLTMODE Fact is NULL in" << __func__ << __FILE__ << __LINE__;
+        return;
+    }
+
+    int flightModeChannel = pFact->rawValue().toInt() - 1;
+
+    pFact = getParameterFact(-1, QString("RC%1_REV").arg(flightModeChannel + 1));
+    if(!pFact) {
+        qCritical() << QString("RC%1_REV").arg(flightModeChannel + 1) << "is NULL in" << __func__ << __FILE__ << __LINE__;
+        return;
+    }
 
-    int flightModeReversed = getParameterFact(1, QString("RC%1_REV").arg(flightModeChannel + 1))->rawValue().toInt();
+    int flightModeReversed = pFact->rawValue().toInt();
 
     if (flightModeChannel < 0 || flightModeChannel > channelCount) {
         return;