flutter TextField external border color

Container(
                              child: TextField(
                                controller: activeCodeEditer,
                                keyboardType: TextInputType.number,
                                focusNode: _nodeText3,
//                                style: TextStyle(fontSize: 14, color: Color(0xff9e51ff)),
                                maxLength: 8,
                                decoration: InputDecoration(
                                  hintText: '请输入激活码',
                                  counterText: "",
//                                icon: Image.asset('assets/images/icons-login-mobile.png', height: 25),
                                  hintStyle: TextStyle(color: Color(0xff9e51ff)),
                                  contentPadding: EdgeInsets.only(left: 10,top: ScreenUtil().setHeight(10)),
                                  border: OutlineInputBorder(
                                      borderRadius: BorderRadius.circular(5.0),
                                      borderSide: BorderSide(color: Color(0xff9e51ff),), //这个不生效
                                  ),
                                  enabledBorder: OutlineInputBorder (// unchecked when the color 
                                    borderRadius: BorderRadius.circular ( 5.0 ), 
                                    borderSide: BorderSide (Color: Color ( 0xff9e51ff ),), 
                                  ), focusedBorder : when OutlineInputBorder (// select external border color 
                                    borderRadius: BorderRadius.circular ( 
                                  5.0 ), 
                                    borderSide: BorderSide (color: color ( 0xff9e51ff ),), 
                                  ), 
//                                   focusedBorder: UnderlineInputBorder (// select the border color nowadays 
 //                                    borderSide: BorderSide(color: Colors.red),
//                                  ),
                                ),
                              ),
                              width: ScreenUtil().setHeight(278),
                              height: ScreenUtil().setHeight(67),
                            )