how to get random ten values after generate random number

public ImageView[] IMGS = { iv1, iv3, iv3, iv4, iv5, iv6,iv7,iv8,iv9,iv10,iv11,iv12,iv13,iv14,iv15,iv16,iv17,iv18,iv19,iv20 };

for(int i=0;i<20;i++){
    IMGS[i].setVisibility(View.GONE);

}

for(int i=1;i<=10;i++) {`

Random random = new Random(); rndIndex = random.nextInt(IMGS.length);

       IMGS[rndIndex].setVisibility(View.VISIBLE);

}

how to ten random value in imageViews and get dialog after ten value show or click