layout组件问题

[7935201]

对一个垂直从上到下布局的layout，现在有3个结点，此时我希望插入一个结点起位置在最上面，需要怎么修改代码？

[7935201]

用insertChild

[317529039 (let MyWife = new DoubleWife() But I want more wife -Harem 3000 girls)]

zindex