类型 'string' 不是 flutter 和 mysql 中 'index' 类型 'int' 的子类型

Question

class ItemList extends StatelessWidget {
  late List list;
  ItemList({super.key, required this.list});

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      // ignore: unnecessary_null_comparison
      itemCount: list == null ? 0 : list.length,
      itemBuilder: ((context, i) {
        return ListTile(
          leading: Icon(Icons.circle),
          title: Text(list[i]['item_name']),
        );
      }),
    );
  }
}

我的完整代码：

import 'dart:convert';

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

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(),
    );
  }
}

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

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

class _MyHomePageState extends State<MyHomePage> {
  var url = "http://10.0.2.2/my_store/php/get_data.php";

  Future<List> getData() async {
    final response = await http.get(Uri.parse(url));
    return json.decode(response.body);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("MY STORE"),
      ),
      body: FutureBuilder<List>(
          future: getData(),
          builder: (context, snapshot) {
            if (snapshot.hasError) {
              print(snapshot.error);
            }
            return snapshot.hasData
                ? ItemList(
                    list: [snapshot.data],
                  )
                : const Center(
                    child: CircularProgressIndicator(),
                  );
          }),
    );
  }
}

class ItemList extends StatelessWidget {
  late List list;
  ItemList({super.key, required this.list});

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      // ignore: unnecessary_null_comparison
      itemCount: list == null ? 0 : list.length,
      itemBuilder: ((context, i) {
        return ListTile(
          leading: Icon(Icons.circle),
          title: Text(list[i]['item_name']),
        );
      }),
    );
  }
}

任何人都可以帮助我吗？

Answer 1

您可以尝试将字符串类型更改为 int 类型，如下所示

int val = int.tryParse(text) ?? 0;