dart - 如何修复“字符串不是小部件类型的子类型”？

Question

我正在尝试使用 GoogleTranslator 库来翻译输入文本，但我得到一个错误，说类型 String 不是 Widget 类型的子类型

我试图创建一个接收文本并返回翻译文本并使用应用程序主体上的小部件的函数

import 'package:flutter/material.dart';
import 'package:translator/translator.dart';

void main() => runApp(MyApp());

Widget translator(String input) {
  GoogleTranslator translator = GoogleTranslator();

  String translation = translator
      .translate("I would buy a car, if I had money.", from: 'en', to: 'ar')
      .toString();
  return translation as Widget;
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Translator'),
        ),
        body: Center(
          child: translator("Hello World"),
        ),
      ),
    );
  }
}

我希望输出在屏幕中央的翻译文本中

Answer 1

return translation as Widget;

应该是

return Text(translation);

更新

import 'package:flutter/material.dart';
import 'package:translator/translator.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Translator'),
        ),
        body: Center(
          child: MyHomePage(),
        ),
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final _translations = <String,String>{};

  String translator(String input) {
    if(_translations.containsKey(input)) {
      return _translations[input];
    } else {
      _translate(input);
      return input;
    }
  }

  Future<void> _translate(String input) async { 
    GoogleTranslator translator = GoogleTranslator();

    String translation = await translator
        .translate("I would buy a car, if I had money.", from: 'en', to: 'ar');
    setState(() => _translations[input] = translation);
  }

  @override
  Widget build(BuildContext context) {
    return Text(translator("Hello World"));
  }
}