private void resetDrawable(){
        for(View i : mIndicators){
            if(mPreviousSelectedIndicator!= null && mPreviousSelectedIndicator.equals(i)){
                ((ImageView)i).setImageDrawable(mSelectedDrawable);
            }
            else{
                ((ImageView)i).setImageDrawable(mUnselectedDrawable);
            }
        }
    }
bind indicator with viewpagerEx.
@param pager
library/src/main/java/com/daimajia/slider/library/Indicators/PagerIndicator.java