TextField(

          decoration: InputDecoration(

                focusedBorder: OutlineInputBorder(

                  borderSide: BorderSide(color: Colors.blue, width: 2.0),

                ),

                enabledBorder: OutlineInputBorder(

                  borderSide: BorderSide(color: Colors.green, width: 2.0),

                ),

               hintText: 'Enter your name',

              ),

            ),

new TextField(

  decoration: new InputDecoration(

    enabledBorder: const OutlineInputBorder(

      // width: 0.0 produces a thin "hairline" border

      borderSide: const BorderSide(color: Colors.grey, width: 0.0),

    ),

    border: const OutlineInputBorder(),

    labelStyle: new TextStyle(color: Colors.green),

    ...

  ),

)