private int getEdgesTouched(int x, int y) {
        int result = 0;

        if (x < mParentView.getLeft() + mEdgeSize) result |= EDGE_LEFT;
        if (y < mParentView.getTop() + mEdgeSize) result |= EDGE_TOP;
        if (x > mParentView.getRight() - mEdgeSize) result |= EDGE_RIGHT;
        if (y > mParentView.getBottom() - mEdgeSize) result |= EDGE_BOTTOM;

        return result;
    }
Find the topmost child under the given point within the parent view's coordinate system.
The child order is determined using {@link Callback#getOrderedChildIndex(int)}.

@param x X position to test in the parent's coordinate system
@param y Y position to test in the parent's coordinate system
@return The topmost child view under (x, y) or null if none found.
app/src/main/java/home/smart/fly/animations/widget/slidepanel/ViewDragHelper.java