Android :: Random Number Card Displaying Error

I m generating one random card from array. and assigning it.'
Below is the code..but its is showing an error. What is the problem?

public void rand() {String rank[]= {"tclub1.png", "tclub2.png", "tclub3.png", "tclub4.png", "tclub5.png", "tclub6.png", "tclub7.png", "tclub8.png", "tclub9.png", "tclub10.png","tclub11.png", "tclub12.png", "tclub13.png"};Random randInt = new Random();int b = randInt.nextInt((rank.length));showcard1.setBackgroundResource(b);}