Ensuring a static var stays updated

Question

Sorry for spamming the boards but I have another question...
I want to get the index of the image currently in the center of the carousel and then I want to use this index number in other classes but it has to stay updated each time. I successfully managed to get the index of the image that is currently being clicked on (this image will then be moved to the center of the carousel so as long as one always clicks on an image at the start, my method will work ) but I dont know how to allow other classes to access this. I tried saving it as a static var and then trying to access it by using the following:
private var coverIndex : int = CoverFlow.selectedCoverIndex;
But I receive the error msg that selectedCoverIndex is not available to static class CoverFlow or something of that sort. This is what my CoverFlow code looks like (i.e. where I determine which image I want to position in the center):
public class CoverFlow extends Sprite {
  public var covers : Vector.<DisplayObject>;
  private var cover : DisplayObject;
  private var coverIndex : int;
  private static var selectedCoverIndex : int; // Create a static coverIndex so I can easily use this data for external classes
  private function show(id : uint) : void // e : Event
   for (var i : Number = 0;i < covers.length; i++)
    cover = covers[i];
    // Tried putting if i == id as last statment to stop website coming up automatically but it still does since it then loops through again.
    if (i < id)
     setChildIndex(cover, i);
     TweenLite.to(cover, tweenDuration, {x: (id - i + 1) * -coverDistance, z: coverZ, rotationY: -coverRotationY, ease:easing });
    } else if (i > id)
     setChildIndex(cover, covers.length - 1 - i);
     TweenLite.to(cover, tweenDuration, {x: ((i - id + 1) * coverDistance), z: coverZ, rotationY: coverRotationY, ease:easing });
    } else if(i == id)
     setChildIndex(cover, covers.length - 1);
     TweenLite.to(cover, tweenDuration, {x: 0, z: selectedCoverZ, rotationY: 0, ease:easing });
  //____________________________________________________________________________Mouse functions on CoverFlow
  private function onClick(event : MouseEvent) : void
   // Always display product clicked on as center image
   cover = event.target as DisplayObject;
   coverIndex = covers.indexOf(cover);
   show(coverIndex); // Show the index number of the current displayed object
   selectedCoverIndex = getCoverIndex();
   trace("Index of Selected Cover : " + selectedCoverIndex);
  //____________________________________________________________________________Getters
  public function getCoverIndex() : int
   trace("Cover Index: " + coverIndex);
   return coverIndex;
Hope you understand what I mean!!

Answer 1

How stupid of me!!!
I am not 100% sure it worked though... To start off it returns the current value (null) but then once I have clicked on one of the images, the coverIndex should change to the corresponding value. In the CoverFlow class it changes to a different value but I am not sure it does in the ProductSummaryLabel class (the latter is the class that imports the value from the CoverFlow class). The reason I believe this is that when in the CoverFlow I call the method setLabel from the ProductSummaryLabel class, which in turn is supposed to find the text in an array of texts which corresponds to the same index as that of the coverIndex, I receive athe following error message: "cannot reach a property or method with a null object reference". This seems to indicate that this variable in the ProductSummaryLabel class still contains the original null value and does not update itself.
This is what my setLabel method in ProductSummaryLabel class looks like:
public function setLabel() : void
   // Summary text depends on coverIndex, i.e. which image is currently in the center
   coverIndex = CoverFlow.selectedCoverIndex; // This should update itself each time I call the setLabel method!
   trace("Cover Index (Product Summary Label class setLabel()): " + coverIndex);
   var desiredSummaryString : String = uebersicht[coverIndex];
   trace("Product summary text: " + desiredSummaryString);
   productSummaryLabel.text = desiredSummaryString;
   productSummaryLabel.visible = true;
   trace("Step 10: Summary loaded");
Below is the method in the CoverFlow class which gets the current coverIndex value and below that is the method which calls the setLabel method from the ProductSummaryLabel class (where pl is declared above as  private var pl : ProductSummaryLabel;).
public function getCoverIndex() : int
   return coverIndex;
private function onClick(event : MouseEvent) : void
   // Always display product clicked on as center image
   cover = event.target as DisplayObject;
   coverIndex = covers.indexOf(cover);
   show(coverIndex); // Show the index number of the current displayed object
   selectedCoverIndex = getCoverIndex();
   trace("Index of Selected Cover : " + selectedCoverIndex);
   // Ensures the text of prodctSummaryLabel is updated
   pl.setLabel();