无法将参数类型“StatelessWidget”分配给参数类型“IconData”

Question

我正在创建一个包含 10 个以上文本框的表单，因此我创建了一个小部件“textformfield”并将其命名为可重用小部件。我也想在每个文本框上都有一个图标，它会根据文本框内容而有所不同。

这是我做的

import 'package:flutter/material.dart';
//import 'package:attendance_system_app/new.dart';

class Textformfield extends StatelessWidget {
  final String hinttext;
  final double font;
  final Color fontcolor;
  final Icon icon;
  final FontWeight fontweight;
  final TextEditingController controller;
  const Textformfield({
    Key key,
    this.hinttext,
    this.font,
    this.icon,
    this.fontcolor,
    this.fontweight,
    this.controller
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return TextFormField(
          controller: controller,
          keyboardType: TextInputType.text,
          decoration: InputDecoration(
            hintText:hinttext,
            isDense: true, 
            contentPadding: EdgeInsets.fromLTRB(10, 10, 10, 0),
            prefixIcon: Icon(
              icon == null ? Container() : 
             icon,
              //color: Colors.blue,
            ),
            hintStyle: TextStyle(
                fontStyle: FontStyle.normal,
                fontSize: 16,
                color: Colors.grey,
                ),
            enabledBorder: new OutlineInputBorder(
                borderRadius: const BorderRadius.all(Radius.circular(12)),
              borderSide: new BorderSide(
                  color: Colors.black, width: 2,),
            ),
            focusedBorder: new OutlineInputBorder(
              borderSide: new BorderSide(
                  color: Colors.black, width: 2),
            ),
          ));
          
      
   
  }
}

但它给我的图标错误，这是错误的快照