如何修復錯誤“無法將引數型別‘動態函式（）’分配給引數型別‘類名’”在Flutter中

我一直在第 48 行第 101 列 ( .push(MaterialPageRoute(builder: (_) => SearchPage(HomeApp, getBooks: getBooks)));)處收到錯誤訊息，“無法將引數型別‘動態函式()’分配給引數型別‘HomeApp’”。我最近開始學習 Flutter/dart，對這些錯誤知之甚少。

// ignore_for_file: void_checks

import 'package:http/http.dart' as http;
import 'package:googleapis/books/v1.dart';
import 'dart:async';
import 'dart:convert';

import 'package:flutter/material.dart';

import 'package:book_search_app/widgets/book_card.dart';
import 'package:book_search_app/screens/profile.dart';

class HomeApp extends StatefulWidget {
  const HomeApp({Key? key}) : super(key: key);

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

class _HomeAppState extends State<HomeApp> {
  getBooks() async {
    var response = await http.get(Uri.parse(
        'https://www.googleapis.com/books/v1/volumes?q={search}:keyes&key={api key}'));
    print(response.body);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: PreferredSize(
          preferredSize: const Size.fromHeight(106),
          child: AppBar(
            automaticallyImplyLeading: false,
            shape: const RoundedRectangleBorder(
                borderRadius:
                    BorderRadius.vertical(bottom: Radius.circular(15))),
            backgroundColor: const Color(0xFFC4C4C4),
            title: const Text(
              'Book Search',
              style: TextStyle(fontSize: 24, color: Colors.black),
            ),
            actions: [
              IconButton(
                onPressed: () {
                  Navigator.of(context)
                      .push(MaterialPageRoute(builder: (_) => SearchPage(HomeApp, getBooks: getBooks)));
                },
                icon: const Icon(Icons.search_rounded),
                iconSize: 40,
                color: Colors.black,
              )
            ],
          ),
        ),
        body: const BookCard(),
        bottomNavigationBar: ClipRRect(
          borderRadius: const BorderRadius.vertical(top: Radius.circular(15)),
          child: BottomNavigationBar(
            type: BottomNavigationBarType.fixed,
            backgroundColor: const Color(0xFFC4C4C4),
            items: const [
              BottomNavigationBarItem(icon: Icon(Icons.home), label: 'Home'),
              BottomNavigationBarItem(
                  icon: Icon(Icons.category), label: 'Categories'),
              BottomNavigationBarItem(
                  icon: Icon(Icons.favorite), label: 'Favourite'),
              BottomNavigationBarItem(
                  icon: Icon(Icons.shopping_cart), label: 'Cart'),
              BottomNavigationBarItem(
                icon: Icon(Icons.account_circle_rounded),
                label: 'Profile',
              ),
            ],
          ),
        ));
  }
}

class SearchPage extends StatelessWidget {
  // ignore: non_constant_identifier_names
  SearchPage(HomeApp, {Key? key, required this.getBooks,})
      : super(key: key);

  final myController = TextEditingController();
  final HomeApp getBooks;

  @override
  void dispose() {
    myController.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          // The search area here
          title: Container(
        width: double.infinity,
        height: 40,
        decoration: BoxDecoration(
            color: Colors.white, borderRadius: BorderRadius.circular(5)),
        child: Center(
          child: TextField(
            controller: myController,
            decoration: InputDecoration(
                prefixIcon: const Icon(Icons.search),
                suffixIcon: IconButton(
                  icon: const Icon(Icons.search),
                  onPressed: () {
                    getBooks;
                  },
                ),
                hintText: 'Search...',
                border: InputBorder.none),
          ),
        ),
      )),
    );
  }
}

如果有人可以幫助并解釋這個錯誤，我將不勝感激。

uj5u.com熱心網友回復：

錯誤是因為您傳遞了SearchPage 中的getbooks引數型別，HomeApp并且在其中傳遞了一個dynamic函式引數。要解決此問題，您需要對代碼進行以下更改

class SearchPage extends StatelessWidget {
  // ignore: non_constant_identifier_names
  SearchPage(HomeApp, {Key? key, required this.getBooks,})
      : super(key: key);

  final myController = TextEditingController();
  final Function getBooks;

標籤：扑 镖

上一篇：動態地將ChartAreas添加到圖表中的一列，并使圖表在winforms中可自動滾動

下一篇：有效地創建具有不同文本的多個相同小部件的方法