PagerIndicator.java

public class PagerIndicator extends View {
    // Constructors and other methods

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (isInEditMode()) {
            drawDots(canvas, 5, 2);
            return;
        }

        if (pager != null) {
            int total = pager.getAdapter().getCount();
            int currentPage = pager.getCurrentItem();

            drawDots(canvas, total, currentPage);
        }
    }
}