java - 在Android中，我如何按日期对数组项进行分组？

Question

对象的数组

    Statement:[
       {
       "date": "12-09-19 11:02:47",
       "Country": "Bangladesh",
       "Profession": "X",
       "Salary": "100",
       },
       {
       "date": "12-09-19 11:02:47",
       "Country": "Bangladesh",
       "Profession": "Y",
       "Salary": "101",
       },
       {
       "date": "12-09-19 11:02:47",
       "Country": "Bangladesh",
       "Profession": "Z",
       "Salary": "102",
       },
       {
       "date": "11-09-19 11:02:47",
       "Country": "India",
       "Profession": "I",
       "Salary": "103",
       },
       {
       "date": "11-09-19 11:02:47",
       "Country": "India",
       "Profession": "J",
       "Salary": "104",
       },
       {
       "date": "10-09-19 11:02:47",
       "Country": "Nepal",
       "Profession": "N",
       "Salary": "105",
       },
       {
       "date": "10-09-19 11:02:47",
       "Country": "Nepal",
       "Profession": "M",
       "Salary": "106",
       }
       ]

我正在尝试创建一个新的数组，它将创建一个对象，其中每个日期(作为键)和同一对象中的其他信息.

新数组应如下所示:

    "10-09-19": [
    {
      "Country": "Nepal",
      "Profession": "M",
      "Salary": "106",
    },
    {
      "Country": "Nepal",
      "Profession": "N",
      "Salary": "105",
    }
    ],
    "11-09-19": [{
      "Country": "India",
      "Profession": "J",
       "Salary": "104",
    },
    {
      "Country": "India",
      "Profession": "I",
      "Salary": "103",
    }
    ],
    "12-09-19": [{
      "Country": "Bangladesh",
      "Profession": "x",
       "Salary": "104",
    },
    {
      "Country": "Bangladesh",
      "Profession": "y",
      "Salary": "103",
    },
    {
      "Country": "Bangladesh",
      "Profession": "z",
      "Salary": "102",
    }
    ]

Answer 1

使用 hashmap 来存储数据日期。 HashMap 的键将是日期。 这是我的代码，它可能会帮助您理解逻辑。

      var sortedList= HashMap<String, MutableList<Model>>() // create hashmap to store data
        var temp: MutableList<Model>? = ArrayList<Model>()
        for (item in currentList!!) {
            temp = sortedList?.get(item.date.split(" ").get(0)) // get date and remove timing

            if (temp != null)     //if this is not null it mean this contain items
                temp.add(item)
            else {
                temp = ArrayList<Model>()  //if this is null it means this is new data or new data
                temp.add(item)
            }

            sortedList?.put(item.date.split(" ").get(0), temp)
    }

我的代码是用 kotlin 编写的，对此深表歉意。 快乐编码。