public void setFadeOnClickListener(OnClickListener listener) {
        mFadeOnClickListener = listener;
    }
Provides an on click for the portion of the main view that is dimmed. The listener is not
triggered if the panel is in a collapsed or a hidden position. If the on click listener is
not provided, the clicks on the dimmed area are passed through to the main layout.

@param listener
app/src/main/java/home/smart/fly/animations/widget/slidepanel/SlidingUpPanelLayout.java