要在Flutter中删除TextField下划线，您可以简单地使用InputBorder.none。

TextField(
  decoration: InputDecoration(
    hintText: 'Hint Text',
    border: InputBorder.none,
  ),
)

我发现没有其他答案给出边界半径，你可以简单地这样做，没有嵌套的容器

  TextField(
    decoration: InputDecoration(
      border: OutlineInputBorder(
        borderSide: BorderSide.none,
        borderRadius: BorderRadius.circular(20),
      ),
    ),
  );

            Container(
         height: 50,
          // margin: EdgeInsets.only(top: 20),
          decoration: BoxDecoration(
              color: Colors.tealAccent,
              borderRadius: BorderRadius.circular(32)),
          child: TextFormField(
            cursorColor: Colors.black,
            // keyboardType: TextInputType.,
            decoration: InputDecoration(
              hintStyle: TextStyle(fontSize: 17),
              hintText: 'Search your trips',
              suffixIcon: Icon(Icons.search),
              border: InputBorder.none,
              contentPadding: EdgeInsets.all(18),
            ),
          ),
        ),

新的Flutter SDK，因为在集成了web和桌面支持之后，你需要像这样单独指定:

TextFormField(
  cursorColor: Colors.black,
  keyboardType: inputType,
  decoration: InputDecoration(
    border: InputBorder.none,
    focusedBorder: InputBorder.none,
    enabledBorder: InputBorder.none,
    errorBorder: InputBorder.none,
    disabledBorder: InputBorder.none,
    contentPadding:
      EdgeInsets.only(left: 15, bottom: 11, top: 11, right: 15),
    hintText: "Hint here"),
)

删除下划线边框:InputBorder.none

对于提示，使用hintText: ' hintText '

   TextFormField(
      InputDecoration(
        border: InputBorder.none,
        hintText: 'Hint Text',
      ),
    ),

decoration: InputDecoration(
 border:OutLineInputBorder(
 borderSide:BorderSide.none
 bordeRadius: BordeRadius.circular(20.0)
 )
)