实现有关GUI建立两图标之间连线的例子 1）首先实现图标的拖拉 2）实现图标间添加连线的方法 3）连线可自动适应其起始、终止接点位置变化 -Realize the establishment of the two icons on the GUI example of the connection between 1) First of all realize the drag icon 2) realize the icon to add the connection betw