小编lat*_*der的帖子

关于这个问题我似乎没有任何错误.我已经在app.module.ts中导入并将其放入'声明'中.

在app.module.ts中

import { NgModule, ErrorHandler } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { IonicApp, IonicModule, IonicErrorHandler } from 'ionic-angular';
import { MyApp } from './app.component';

//ionic-native
import { NativeStorage } from '@ionic-native/native-storage';
import { StatusBar } from '@ionic-native/status-bar';
import { SplashScreen } from '@ionic-native/splash-screen';

//pipe
import { HoursMinutesSecondsPipe } from '../pipes/hours-minutes-
seconds/hours-minutes-seconds';

@NgModule({
declarations: [
MyApp,
HoursMinutesSecondsPipe
],
imports: [
BrowserModule,
IonicModule.forRoot(MyApp, {
  platforms: {
    android: {
      tabsPlacement: 'top'
    }
  }
}),
],
bootstrap: [IonicApp],
entryComponents: …

我是 Flutter 新手。\n我想从列表变量中显示 DropdownMenuItem。\n查看我的代码。

\n// my list variable\n\n\n  List listUserType = [\n    {'name': 'Individual', 'value': 'individual'},\n    {'name': 'Company', 'value': 'company'}\n  ];\n\n\n\n\n// items property in DropdownMenuItem\n\nreturn DropdownButtonFormField<List<Map>>(\n        decoration: InputDecoration(\n          prefixIcon: Icon(Icons.settings),\n          hintText: 'Organisation Type',\n          filled: true,\n          fillColor: Colors.white,\n          errorStyle: TextStyle(color: Colors.yellow),\n        ),\n        items: listUserType.map((map) {\n          return DropdownMenuItem(\n            child: Text(map['name']),\n            value: map['value'],\n          );\n        }).toList());\n

这是我得到的结果

I/flutter (22528): \xe2\x95\x90\xe2\x95\x90\xe2\x95\xa1 EXCEPTION CAUGHT BY WIDGETS LIBRARY \xe2\x95\x9e\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\nI/flutter (22528): The following assertion was thrown building RegisterPage(dirty, state: RegisterPageState#5b83a):\nI/flutter (22528): type 'List<DropdownMenuItem<dynamic>>' is not …