public final void translate(double dx,
double dy)Translates the current item transformation by (dx, dy).
If all you want is to move an item, you should call moveBy() or setPos() instead; this function changes the item's translation, which is conceptually separate from its position.
这个函数只是把原点设为你要的点,并没有移动物体,注意,并非原点一定就在左上角。换句话说,移动的是坐标轴,而不是物体。用moveBy() or setPos() 来移动物体