Flutter中PopupMenuButton下拉菜单按钮

PopupMenuButton参数

const PopupMenuButton({
  Key key,
  @required this.itemBuilder,//渲染下拉菜单函数，返回数组
  this.initialValue,//默认选中
  this.onSelected,//选择改变触发
  this.onCanceled,
  this.tooltip,//提示
  this.elevation,//阴影
  this.padding = const EdgeInsets.all(8.0),
  this.child,
  this.icon,
  this.offset = Offset.zero,
  this.enabled = true,
  this.shape,
  this.color,
  this.captureInheritedThemes = true,
})

child: PopupMenuButton(
 

  onSelected: (value){
    print(value);
  },
  itemBuilder: (BuildContext context) => [
    PopupMenuItem(
      value: 'home',
      child: Text('Home'),
    ),
    PopupMenuItem(
      value: 'product',
      child: Text('product'),
    )
  ],

),