final String keyStr = categoryJson.getKeyStr();
ClickHandler categoryClickHandler = getCategoryClickHandler(keyStr);
Panel itemPanel = createShopItemPanel(categoryJson);
itemPanel.addDomHandler(categoryClickHandler, ClickEvent.getType());
//init background image
final String backgroundBlobKey = categoryJson.getBackgroundBlobKey();
initBackgroundImage(itemPanel, backgroundBlobKey);