Modified fly cam to be a little more resilient

in the face of being called before it sees an
input manager.


git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@9162 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/core/com/jme3/input/FlyByCamera.java

@@ -124,7 +124,7 @@ public class FlyByCamera implements AnalogListener, ActionListener {
      */
     public void setEnabled(boolean enable){
         if (enabled && !enable){
-            if (!dragToRotate || (dragToRotate && canRotate)){
+            if (inputManager!= null && (!dragToRotate || (dragToRotate && canRotate))){
                 inputManager.setCursorVisible(true);
             }
         }
@@ -161,8 +161,10 @@ public class FlyByCamera implements AnalogListener, ActionListener {
      */
     public void setDragToRotate(boolean dragToRotate) {
         this.dragToRotate = dragToRotate;
+        if (inputManager != null) {
             inputManager.setCursorVisible(dragToRotate);
         }
+    }
 
     /**
      * Registers the FlyByCamera to receive input events from the provided
@@ -199,7 +201,7 @@ public class FlyByCamera implements AnalogListener, ActionListener {
         inputManager.addMapping("FLYCAM_Lower", new KeyTrigger(KeyInput.KEY_Z));
 
         inputManager.addListener(this, mappings);
-        inputManager.setCursorVisible(dragToRotate);
+        inputManager.setCursorVisible(dragToRotate || !isEnabled());
 
         Joystick[] joysticks = inputManager.getJoysticks();
         if (joysticks != null && joysticks.length > 0){
@@ -218,6 +220,10 @@ public class FlyByCamera implements AnalogListener, ActionListener {
      */
     public void unregisterInput(){
     
+        if (inputManager == null) {
+            return;
+        }
+    
         for (String s : mappings) {
             inputManager.deleteMapping( s );
         }