@Override
	public FieldLocation getFieldLocation(ListingField bf, BigInteger index, int fieldNum,
			ProgramLocation loc) {

		if (!(loc instanceof VariableXRefFieldLocation)) {
			return null;
		}

		Object obj = bf.getProxy().getObject();
		if (obj instanceof Variable) {
			Variable sv = (Variable) obj;
			VariableXRefFieldLocation varXRefLoc = (VariableXRefFieldLocation) loc;
			if (varXRefLoc.isLocationFor(sv)) {
				return createFieldLocation(varXRefLoc.getCharOffset(), varXRefLoc.getIndex(),
					(ListingTextField) bf, index, fieldNum);
			}
		}

		return null;
	}
Constructor
@param model the model that the field belongs to.
@param hlProvider the HighlightProvider.
@param displayOptions the Options for display properties.
@param fieldOptions the Options for field specific properties.
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/field/VariableXRefFieldFactory.java