Flutter 圆角半透明编辑框

 Container(
            alignment: Alignment.center,
            margin: EdgeInsets.all(5),
            padding: EdgeInsets.only(left: 15, right: 15),
            decoration: BoxDecoration(
              color: Colors.black12,
              borderRadius: BorderRadius.all(Radius.circular(20)),
            ),
            child: TextField(
              cursorColor: Colors.black,
              cursorWidth: 1,
              decoration: InputDecoration(
                border: InputBorder.none, //无边框
              ),
            ),
          ),