public boolean isDragging() {
        return mDragState == STATE_DRAGGING;
    }
Check if any of the edges specified were initially touched by the pointer with
the specified ID. If there is no currently active gesture or if there is no pointer with
the given ID currently down this method will return false.

@param edges Edges to check for an initial edge touch. See {@link #EDGE_LEFT},
             {@link #EDGE_TOP}, {@link #EDGE_RIGHT}, {@link #EDGE_BOTTOM} and
             {@link #EDGE_ALL}
@return true if any of the edges specified were initially touched in the current gesture
app/src/main/java/home/smart/fly/animations/widget/slidepanel/ViewDragHelper.java