Flutter：如何从 API 端的对象数组中获取最新日期？

Question

我在项目中使用flutter。

我从服务器获取对象数组。每个对象包含几个属性，其中之一是日期属性。

这是我从服务器获取的数组（json 格式）：

{
    "drainageid": "",
    "datacount": 98359,
    "resultcount": 98359,
    "page": "",
    "rows": [
        {
            "id": "DR/C1/IC/H/-/GPG/PU/-/RCP/01",
            "dateoflastinsp": null,
            "dateofinsp": "2001-10-10T00:00:00",
            "inspby": "SAW/ZAG"
        },
        {
            "id": "DR/C1/IC/H/-/GPG/PU/-/RCP/01",
            "dateoflastinsp": "2001-10-10T00:00:00",
            "dateofinsp": "2002-09-24T00:00:00",
            "inspby": "SAW+NBN"
        },
        {
            "id": "DR/C1/IC/H/-/GPG/PU/-/RCP/01",
            "dateoflastinsp": "2002-09-24T00:00:00",
            "dateofinsp": "2003-09-18T00:00:00",
            "inspby": "SAW/NBN"
        },
        {
            "id": "DR/C1/IC/H/-/GPG/PU/-/RCP/01",
            "dateoflastinsp": "2003-09-18T00:00:00",
            "dateofinsp": "2004-09-08T00:00:00",
            "inspby": "SAW/NBN"
        },
        {
            "id": "DR/C1/IC/H/-/GPG/PU/-/RCP/01",
            "dateoflastinsp": "2004-09-08T00:00:00",
            "dateofinsp": "2005-05-05T00:00:00",
            "inspby": "MZB/ASMG"
        },
        {
            "id": "DR/C1/IC/H/-/GPG/PU/-/RCP/01",
            "dateoflastinsp": "2005-05-05T00:00:00",
            "dateofinsp": "2006-05-04T00:00:00",
            "inspby": "MZB/ASZ"
        },
        {
            "id": "DR/C1/IC/H/-/GPG/PU/-/RCP/01",
            "dateoflastinsp": "2006-05-04T00:00:00",
            "dateofinsp": "2007-05-09T00:00:00",
            "inspby": "Ahmad/Haizul"
        },
        {
            "id": "DR/C1/IC/H/-/GPG/PU/-/RCP/01",
            "dateoflastinsp": "2007-05-09T00:00:00",
            "dateofinsp": "2008-05-07T00:00:00",
            "inspby": "Harzazi/Zulkornain"
        },
}

我需要从

dateoflastinsp

列表中的数组中获取最新日期

rows

。

如何从flutter中的对象数组中获取最新日期？

Answer 1

您可以使用

List.sort

并比较日期。

String jsonData = '''
  {
    "drainageid": "",
    "datacount": 98359,
    "resultcount": 98359,
    "page": "",
    "rows": [
      {
        "id": "DR/C1/IC/H/-/GPG/PU/-/RCP/01",
        "dateoflastinsp": null,
        "dateofinsp": "2001-10-10T00:00:00",
        "inspby": "SAW/ZAG"
      }...
 ''';


// Parse the JSON data
  Map<String, dynamic> data = jsonDecode(jsonData);

  // Sort the rows by dateofinsp in ascending order
  List<Map<String, dynamic>> rows = List<Map<String, dynamic>>.from(data['rows']);
  rows.sort((a, b) => DateTime.parse(a['dateofinsp']).compareTo(DateTime.parse(b['dateofinsp'])));

  // Print the sorted rows
  for (Map<String, dynamic> row in rows) {
    print(row);
  }

输出

{id: DR/C1/IC/H/-/GPG/PU/-/RCP/01, dateoflastinsp: null, dateofinsp: 2001-10-10T00:00:00, inspby: SAW/ZAG}
{id: DR/C1/IC/H/-/GPG/PU/-/RCP/01, dateoflastinsp: 2001-10-10T00:00:00, dateofinsp: 2002-09-24T00:00:00, inspby: SAW+NBN}
{id: DR/C1/IC/H/-/GPG/PU/-/RCP/01, dateoflastinsp: 2002-09-24T00:00:00, dateofinsp: 2003-09-18T00:00:00, inspby: SAW/NBN}
{id: DR/C1/IC/H/-/GPG/PU/-/RCP/01, dateoflastinsp: 2003-09-18T00:00:00, dateofinsp: 2004-09-08T00:00:00, inspby: SAW/NBN}
{id: DR/C1/IC/H/-/GPG/PU/-/RCP/01, dateoflastinsp: 2004-09-08T00:00:00, dateofinsp: 2005-05-05T00:00:00, inspby: MZB/ASMG}
{id: DR/C1/IC/H/-/GPG/PU/-/RCP/01, dateoflastinsp: 2005-05-05T00:00:00, dateofinsp: 2006-05-04T00:00:00, inspby: MZB/ASZ}
{id: DR/C1/IC/H/-/GPG/PU/-/RCP/01, dateoflastinsp: 2006-05-04T00:00:00, dateofinsp: 2007-05-09T00:00:00, inspby: Ahmad/Haizul}
{id: DR/C1/IC/H/-/GPG/PU/-/RCP/01, dateoflastinsp: 2007-05-09T00:00:00, dateofinsp: 2008-05-07T00:00:00, inspby: Harzazi/Zulkornain}