从 rest API 为 Category 创建一个 ListView，而不在 Flutter 中重复

Question

[
  {
    "category": "Apple",
    "name": "Macbook Air"
  }, {
    "category": "Apple",
    "name": "Macbook Pro"
  }, {
    "category": "Microsoft",
    "name": "Surface"
  }, {
    "category": "Apple",
    "name": "iPad"
  }, {
    "category": "Microsoft",
    "name": "Windows"
  }, {
    "category": "Apple",
    "name": "Siri"
  }, {
    "category": "Microsoft",
    "name": "Office"
  }
]

我需要从上面示例的 Rest API 数据中将公共类别放入 ListView。

有Apple&Microsoft是这6个数据中共同的类别

它是自动完成的。

你能给出解决方案吗？

Answer 1

  List getCategory(List data) {
    List list = [];
    for (var a in data) 
      if (!list.contains(a["category"]))
       list.add(a["category"]);
    return list;
  }

Answer 2

import 'dart:convert';

import 'dart:math';

const source = '''
{
    "data": [
        { "category": "Apple", "name": "Macbook Air" },
        { "category": "Apple", "name": "Macbook Pro" },
        { "category": "Microsoft", "name": "Surface" },
        { "category": "Apple", "name": "iPad" },
        { "category": "Microsoft", "name": "Windows" },
        { "category": "Apple", "name": "Siri" },
        { "category": "Microsoft", "name": "Office" }
    ]
}
''';

main(List<String> args) {
  final List data = jsonDecode(source)['data'];
  
  var mode = Map<String, int>();

  data.map<String>((e) => (e as Map)['category']).forEach((k) => mode[k] = (mode[k] ?? 0) + 1);

  var maxVal = mode.values.toList().reduce(max);
  var category = List<String>();

  mode.forEach((k, v) => v==maxVal ? category.add(k) : null);

  print(category.toString());
}

从 rest API 为 Category 创建一个 ListView，而不在 Flutter 中重复

Make a ListView from rest API for Category only without duplication in Flutter

rest

listview

dart

flutter