public void setDragView(int dragViewResId) {
        mDragViewResId = dragViewResId;
        setDragView(findViewById(dragViewResId));
    }
Set the draggable view portion. Use to null, to allow the whole panel to be draggable

@param dragViewResId The resource ID of the new drag view
app/src/main/java/home/smart/fly/animations/widget/slidepanel/SlidingUpPanelLayout.java