Question

I want to add an image to an ImageButton depending on a number between 0 and 10. My getNumber method is:

    public int getNumber(){
    // get a random number between 0 and 10
    Random randomNumber = new Random();
    num = randomNumber.nextInt(10);
    return num;
}

I want every image to be unique but the problem I was having was that if numList did contain num it just would leave the button blank. I’ve tried to call permuteButton again recursively until num is not contained within my list but this does not seem to work.

    public void  permuteButton(ImageButton btn){    

        getNumber();

        for(int i=0; i<=numList.size(); i++){
            //check if the number is already being used
            if( numList.contains(num) ){
                permuteButton(btn);
            }
            // else the list doesnt have the number so assign the picture and add number to list
            else{
                numList.add(num);
                assignPictures(btn);
            }
        }
    }

Any help would be appreciated. I’m sorry if this is a simple question.

Answer 1

My answer is similar to the last suggestion from Jon Skeet.

// might be more than 10 ImageButtons, with only 10 images
for (ImageButton imageButton : imageButtons)  
   imageButton.putImage(randomImage.next());

...

public class RandomImage {
   private final List<Image> shuffledImages;
   private int currentIndex;

   public RandomImage(List<Image> images) {
      shuffledImages = new ArrayList<>(images.size());
      shuffledImages.addAll(images);
      currentIndex = -1;
   }

   public Image next() {
      currentIndex++;
      if (currentIndex % shuffledImages.size() == 0) {
         currentIndex = 0;
         Collections.shuffle(shuffledImages);
      }
      return shuffledImages[currentIndex];
   }
}