@Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        if (changed) {
            removeCallbacks(mShowIndicatorRunnable);
            if (!isInEditMode()) {
                mIndicator.dismissComplete();
            }
            updateFromDrawableState();
        }
    }
When the {@link DiscreteSeekBar} value changes this method is called
<p>
Subclasses may override this to add functionality around this event
without having to specify a {@link OnProgressChangeListener}
</p>
app/src/main/java/com/duan/musicoco/view/discreteseekbar/DiscreteSeekBar.java