flutter - flutter react_forms ReactiveForm.of noSuchMethod

Question

我正在尝试禁用reactive_forms中的提交按钮
当我执行此代码时:

import 'package:reactive_forms/reactive_forms.dart';
final form = ReactiveForm.of(context);

我收到此错误:

The following NoSuchMethodError was thrown building VpFormElevatedButton(dirty): The getter 'control' was called on null. Receiver: null Tried calling: control

The relevant error-causing widget was VpFormElevatedButton lib/…/logged_out_nickname/logged_out_nick_name_view.dart:68 When the exception was thrown, this was the stack
#0      Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
#1      ReactiveForm.of package:reactive_forms/…/widgets/reactive_form.dart:55
#2      VpFormElevatedButton.build package:vepo/…/buttons/elevated_button_widget.dart:23
#3      StatelessElement.build package:flutter/…/widgets/framework.dart:4701
#4      ComponentElement.performRebuild package:flutter/…/widgets/framework.dart:4627 ... ════════════════════════════════════════════════════════════════════════════════

════════ Exception caught by rendering library ═════════════════════════════════ A RenderFlex overflowed by 99838 pixels on the bottom. The relevant error-causing widget was Column lib/…/logged_out_nickname/logged_out_nick_name_view.dart:65 The specific RenderFlex in question is: RenderFlex#abc1d relayoutBoundary=up1 OVERFLOWING

它认为 ReactiveForm是一种类型:
final form = ReactiveForm.of(context);是从react_forms文档复制粘贴的。为什么会看到此运行时异常？

Answer 1

如果您确定已经正确分配了变量，并且NoSuchMethodError仍然抛出getter 'value' was called on null。
重新启动或重建应用程序，因为 HotReload 不会调用initState()且此回调是分配变量的位置，因此请尝试重建您的应用程序