Question

我想搜索我的内容，但是我的代码遇到问题。当我单击搜索图标时，它首先不显示任何数据，然后显示错误（引发了另一个异常：类型'（dynamic）=> dynamic'不是'test'类型'（Book）=> bool'的子类型'）。

我这样在主屏幕的AppBar上创建一个搜索图标-

actions: <Widget>[
            FutureBuilder(
                future: fetchBooks(http.Client()),
                builder: (context, snapshot) {
                  return IconButton(
                    icon: Icon(Icons.search),
                    onPressed: () {
                      showSearch(
                          context: context,
                          delegate: BooksSearch(snapshot.data));
                    },
                  );
                }),
          ],

这是我的模特。飞镖-

import 'dart:async';
import 'dart:convert';
import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;

Future<List<Book>> fetchBooks(http.Client client) async {
  final response =
      await client.get('https://boimarket.abirahsan.com/public/api/v1/books');

  // Use the compute function to run parsePhotos in a separate isolate.
  return compute(parseBooks, response.body);
}

// A function that converts a response body into a List<Photo>.
List<Book> parseBooks(String responseBody) {
  final parsed = jsonDecode(responseBody).cast<String, dynamic>();
  return parsed['data'].map<Book>((json) => Book.fromJson(json)).toList();
}

class Book {
  final String name;
  final String author;
  final String html;
  final String description;
  final int category;

  Book({
    this.name,
    this.author,
    this.description,
    this.html,
    this.category,
  });

  factory Book.fromJson(Map<String, dynamic> json) {
    return Book(
      name: json['name'] as String,
      html: json['html'] as String,
      description: json['description'] as String,
      author: json['author'] as String,
      category: json['category'] as int,
    );
  }
}

这是我的booksearch.dart-

import 'package:flutter/material.dart';
import 'package:boimarket/model/model.dart';
import 'package:http/http.dart' as http;

class BooksSearch extends SearchDelegate<Book> {
  BooksSearch(this.allBooksData);

  final allBooksData;

  @override
  List<Widget> buildActions(BuildContext context) {
    return [
      SizedBox(
        width: 5.0,
      ),
      IconButton(
        icon: Icon(Icons.clear),
        onPressed: () {
          query = '';
        },
      )
    ];
  }

  @override
  Widget buildLeading(BuildContext context) {
    return IconButton(
      icon: Icon(Icons.arrow_back),
      onPressed: () {
        close(context, null);
      },
    );
  }

  @override
  Widget buildResults(BuildContext context) {
    return Container();
  }

  @override
  Widget buildSuggestions(BuildContext context) {
    return FutureBuilder(
        future: fetchBooks(http.Client()),
        builder: (context, snapshot) {
          if (!snapshot.hasData) {
            return Center(
              child: Text('No Data'),
            );
          } else {
            final result = allBooksData
                .where((a) => a.name.toLowerCase().contains(query))
                .toList();
            return ListView(
              children: result.map<Widget>((a) => Text(a.name)),
            );
          }
        });
  }
}

我的代码中的问题在哪里？我该如何解决这个错误？

Answer 1

您可以在下面复制粘贴运行完整代码
步骤1：您需要json['name'].toString()的{{1}}
步骤2：为数据类型

指定列表

Unicode

工作演示

完整代码

final List<Book> allBooksData;
...
AsyncSnapshot<List<Book>> snapshot)
...
final List<Book> result

Flutter：“（dynamic）=>动态”类型不是“ test”的“（Book）=> bool”类型的子类型

1 个答案: