轉換列表<list<dynamic> &gt; 到 Flutter 中的 ArrayList </list<dynamic>

Question

我是 flutter 的新手，我想將 List<List> 轉換為 ArrayList。 這是我當前的列表 output

數據 [[數量, Desc, 單價, 總價], [1, 牛仔褲, 106.0, 106.0], [2, 襯衫, 24.38, 24.38], [3, Demo Hoodie / XL, 106.0, 318.0], [4, Demo Hoodie / 2XL, 106.0, 106.0], [1, 牛仔褲-短褲, 106.0, 106.0], [5, 襯衫-長, 24.38, 24.38], [6, Demo Hoodie-Lg / XL, 106.0, 318.0], [4, Demo Hoodie-Mg / 2XL, 106.0, 106.0], [3, Jeans-RG, 106.0, 106.0], [4, Shirt-MG, 24.38, 24.38], [7, Demo Hoodie-TY / XL, 106.0, 318.0] , [9, Demo Hoodie-Levis / 2XL, 106.0, 106.0], [1, Demo Hoodie-J&J / XL, 106.0, 318.0], [2, Demo Hoodie-M&J / 2XL, 106.0, 106.0], [7, Temo Hoodie-TY / XL, 106.0, 318.0], [5, Zemo Hoodie-Levis / 2XL, 106.0, 106.0], [6, Aemo Hoodie-J&J / XL, 106.0, 318.0], [2, Bemo Hoodie-M&J / 2XL , 106.0, 106.0], [9, Temo Hoodie-TY / XL, 106.0, 318.0], [1, Zemo Hoodie-Levis / 2XL, 106.0, 106.0], [2, Aemo Hoodie-J&J / XL, 106.0, 318.0] , [7, Bemo Hoodie-M&J / 2XL, 106.0, 106.0]]

我想將該數組列表添加到 flutter 的 recyclerView 中。

提前致謝。

Answer 1

您可以使用dart:convert並使用jsonDecode但這將不起作用，除非您從中刪除字符串以便為每個單詞添加單引號/雙引號。

或者您可以通過拆分字符串來手動轉換它。

import 'dart:core';

main(){
  
 String data = "[[Qty, Desc, Unitprice, totalprice], [1, Jeans, 106.0, 106.0], [2, Shirt, 24.38, 24.38], [3, Demo Hoodie / XL, 106.0, 318.0], [4, Demo Hoodie / 2XL, 106.0, 106.0], [1, Jeans-short, 106.0, 106.0], [5, Shirt-Long, 24.38, 24.38], [6, Demo Hoodie-Lg / XL, 106.0, 318.0], [4, Demo Hoodie-Mg / 2XL, 106.0, 106.0], [3, Jeans-RG, 106.0, 106.0], [4, Shirt-MG, 24.38, 24.38], [7, Demo Hoodie-TY / XL, 106.0, 318.0], [9, Demo Hoodie-Levis / 2XL, 106.0, 106.0], [1, Demo Hoodie-J&J / XL, 106.0, 318.0], [2, Demo Hoodie-M&J / 2XL, 106.0, 106.0], [7, Temo Hoodie-TY / XL, 106.0, 318.0], [5, Zemo Hoodie-Levis / 2XL, 106.0, 106.0], [6, Aemo Hoodie-J&J / XL, 106.0, 318.0], [2, Bemo Hoodie-M&J / 2XL, 106.0, 106.0], [9, Temo Hoodie-TY / XL, 106.0, 318.0], [1, Zemo Hoodie-Levis / 2XL, 106.0, 106.0], [2, Aemo Hoodie-J&J / XL, 106.0, 318.0], [7, Bemo Hoodie-M&J / 2XL, 106.0, 106.0]]";
  
  
  List<String> splittedData = data.substring(2,data.length-1).split("], [");


  List<List<String>> formattedData = [];

  splittedData.forEach( (stringVal) => formattedData.add(stringVal.split(', ')));

  print(formattedData[0][0]);
  

}

您運行此代碼dartpad.dev以檢查其 output。

您可以通過使用正則表達式來解析數據而不是使用字符串拆分數據來進一步改進這一點。 這將是數據本身不一致並且其中包含單引號/雙引號和方括號的情況。

Answer 2

• 您應該將對象用於這種用途，例如 List<Product> 而不是 List<List>

• Flutter 中沒有 RecyclerView，它是 ListView 小部件。

• 您的字符串應該在引號之間（“”）

這是 ListView 構建器的示例：

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  
  var list = [["data1", "data2"], ["data1","data2"],["data1","data2"]];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: ListView.builder(
          itemCount: list.length,
          itemBuilder: (context, index) {
            return Container(
              color: Colors.grey[200],
              padding: EdgeInsets.symmetric(vertical: 10),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: List.generate(
                  list[index].length,
                  (index2) {
                    return Text(list[index][index2]);
                  }
                )
              ),
            );
          }
        )
      ),
    );
  }
}