DecoratedBox

DecoratedBox:用于设置装饰，给子元素设置背景、边框、渐变

DecorationedBox:(
  decoration:BoxDecoration(
    color:Colors....,
    image:
    border:Border.all(
      color:Color....,
      width:3.0,
      style:BorderStyle.solid
    ),
    borderRadius:BorderRadius.circular(3.0),
    boxShadow:[
      BoxShadow:()
    ],
    gradient:LinearGradient(
      colors:[
        Color.fromRGBO(3,111,255,1.0),
        Color.fromRGBO(3,121,255,1.0),
      ],
      begin:Alignment.topCenter,
      end:Alignment.bottomCenter

 )
 shape:BoxShape.rectangle(circle) ) )

border:取值

border:Border(
  top:BorderSide(
    color:Colors...,
    width:3.0,
    style:Border.solid
  )
)

border:Border.all(
  color:,
  width:
  style:Border.solid
)

borderRadius:圆角取值

borderRadius:BorderRadius.only(
  topLeft:Radius.circular(12.0),
  ...
)
borderRadius:BorderRadius.circular(12.0)

boxShadow:阴影

boxShadow:[
  BoxShadow:(
    color://阴影颜色
    offset:Offset(12.0,11.0),//偏移位置
    blurRadius:4.0,//阴影模糊程度
    spreadRadius:+-3.0//阴影扩散程度
  )
]