ConcurrentModificationException thrown on for each in android

Question

i passing list of tags in forloop for iterate but its raised ConcurrentModificationException

 public void clearTag() {
    List<Tag> tags = binding.search.tagView.getTags();
    Log.d(TAG, "clearTags: " + tags);
    for (Tag tag : tags) {
        Log.d(TAG, "clearTag: " + tag + " " + tag.getLayoutColor());
        if (tag.getLayoutColor() == R.color.red) {
           tags.remove(tag);
        } else if (tag.getLayoutColor() == R.color.blue) {
            tags.remove(tag);
        } else if (tag.getLayoutColor() == R.color.green) {
            tags.remove(tag);
        }
    }
    updateTagVisibility();
    //resetFilter();
}

Answer 1

This is because remove and add operations are not allowed while iterating through an array. So you need to store all elements to remove in different array, then remove them at once. Here is an example:

public void clearTag() {
    List<Tag> tags = binding.search.tagView.getTags();
    List<Tag> tagsToRemove = new ArrayList<>();
    Log.d(TAG, "clearTags: " + tags);
    for (Tag tag : tags) {
        Log.d(TAG, "clearTag: " + tag + " " + tag.getLayoutColor());
        if (tag.getLayoutColor() == R.color.red) {
           tagsToRemove.add(tag);
        } else if (tag.getLayoutColor() == R.color.blue) {
            tagsToRemove.add(tag);
        } else if (tag.getLayoutColor() == R.color.green) {
            tagsToRemove.add(tag);
        }
    }
    tags.removeAll(tagsToRemove);
    updateTagVisibility();
    //resetFilter();
}