Expanded(
   child:ConstrainedBox(
             constraints: BoxConstraints(
               maxHeight: 40,
             ), 
             child: TextField(
               decoration: InputDecoration(
                 contentPadding: EdgeInsets.fromLTRB(10, 0, 10, 15),
                 fillColor: Color(0XFFFFF8F4),
                 filled: true,
                 enabledBorder: OutlineInputBorder(
                   /*边角*/
                   borderRadius: BorderRadius.all(
                     Radius.circular(5), //边角为5
                   ),
                   borderSide: BorderSide(
                     color: Colors.white, //边线颜色为白色
                     width: 1, //边线宽度为2
                   ),
                 ),
                 focusedBorder: OutlineInputBorder(
                     borderSide: BorderSide(
                       color: Colors.white, //边框颜色为白色
                       width: 1, //宽度为5
                     ),
                     borderRadius: BorderRadius.all(
                       Radius.circular(5), //边角为30
                     ),
                 ),
               ),
             ),
           ),
           
         ),