android - Card Game App - Random card but not the same card twice -

i making card game app, when user clicks card image turn random other card. here example:

public class mainactivity extends activity {  int[] cards={r.drawable.aceofspades,r.drawable.aceofhearts,r.drawable.aceofclubs}; static random r = new random();   @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);  }   public void imageclick(view view) {         int n=r.nextint(cards.length);      {     imageview image = (imageview) findviewbyid(r.id.imagedice1);     image.setimageresource(cards[n]);     }    }   } 

i alter code won't possible same card show twice, not untill cards passed. in case when card "aceofspades" next card , card after should not "aceofspades". first image users see "r.drawable.cardback". code changes image "cardback" when cards have been shown. appreciated.

you need put cards (or values 1 52) in array or list, shuffle them. requirement you're describing shuffling does.