使用ExtJS在卡布局中的卡之间切换时加载蒙版

I am using a card layout in one of my views. There are 6 cards in a card Layout. I use image clicks to switch between the cards. Since it takes sometime for the cards to switch from one to another I need to add a loading mask while switching i.e, when I click on the image the loading mask should appear and as soon as the next card is rendered the loading mask should be removed. Could anyone please suggest me a solution to the loading mask problem that I'm facing ? I am using a card layout in one of my views. Th