feat:增加表单组件

lib/views/login.dart

@@ -1,4 +1,6 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_form_builder/flutter_form_builder.dart';
+import 'package:form_builder_validators/form_builder_validators.dart';
 
 class LoginPage extends StatefulWidget {
   const LoginPage({super.key});
@@ -21,7 +23,7 @@ class _LoginPage extends State<LoginPage> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      backgroundColor: Colors.white,
+      backgroundColor: Colors.grey[100],
       body: Form(
         key: _formKey,
         autovalidateMode: AutovalidateMode.onUserInteraction,
@@ -84,40 +86,36 @@ class _LoginPage extends State<LoginPage> {
   }
 
   Widget buildUsernameTextField() {
-    return TextFormField(
+    return FormBuilderTextField(
+      name: 'username',
       decoration: InputDecoration(
         labelText: '账号',
         prefixIcon: Icon(Icons.person),
         hintText: "请输入账号",
         border: OutlineInputBorder(),
+        floatingLabelBehavior: FloatingLabelBehavior.always,
         filled: true,
-        fillColor: Colors.grey[100],
+        fillColor: Colors.white,
       ),
-      validator: (v) {
-        if (v!.isEmpty) {
-          return '请输入账号';
-        }
-      },
+      validator: FormBuilderValidators.required(),
       onSaved: (v) => _username = v!,
     );
   }
 
   Widget buildPasswordTextField(BuildContext context) {
-    return TextFormField(
+    return FormBuilderTextField(
+      name: 'password',
       obscureText: _isObscure, // 是否显示文字
       onSaved: (v) => _password = v!,
-      validator: (v) {
-        if (v!.isEmpty) {
-          return '请输入密码';
-        }
-      },
+      validator: FormBuilderValidators.required(),
       decoration: InputDecoration(
         labelText: "密码",
         prefixIcon: Icon(Icons.lock),
         hintText: "请输入密码",
         border: OutlineInputBorder(),
         filled: true,
-        fillColor: Colors.grey[100],
+        fillColor: Colors.white,
+        floatingLabelBehavior: FloatingLabelBehavior.always,
         suffixIcon: IconButton(
           icon: Icon(Icons.remove_red_eye, color: _eyeColor),
           onPressed: () {