如何在android中使用对象键对json对象进行排序？答案

【问题标题】：How to sort the json object with the object key in android?如何在android中使用对象键对json对象进行排序？
【发布时间】：2013-12-09 10:41:45
【问题描述】：

由于 JSON 对象不可靠，当我从 json 文本文件创建新的 json 对象时，顺序出错。所以我决定重新排序 json 对象。

正确的顺序（Json文件内容）

{
"211": {
        "host": "https:\/\/s3-ap-southeast-1.amazonaws.com\/production-source\/ChangSha\/2013\/12\/09\/0\/0\/A\/Content\/",
        "timestamp": 1386514507,
        "cover": ["15\/Pg015.png",
        "16\/Pg016.png",
        "1\/Pg001.png",
        "2\/Pg002.png"],
        "year": "2013",
        "month": "12",
        "day": "09",
        "issue": "2013-12-09",
        "id": "211"
    },
    "210": {
        "host": "https:\/\/s3-ap-southeast-1.amazonaws.com\/production-source\/ChangSha\/2013\/12\/08\/0\/0\/A\/Content\/",
        "timestamp": 1386415087,
        "cover": ["1\/Pg001.png",
        "2\/Pg002.png",
        "3\/Pg003.png",
        "4\/Pg004.png"],
        "year": "2013",
        "month": "12",
        "day": "08",
        "issue": "2013-12-08",
        "id": "210"
    },
    "209": {
        "host": "https:\/\/s3-ap-southeast-1.amazonaws.com\/production-source\/ChangSha\/2013\/12\/07\/0\/0\/A\/Content\/",
        "timestamp": 1386331278,
        "cover": ["1\/Pg001.png",
        "2\/Pg002.png",
        "3\/Pg003.png",
        "4\/Pg004.png"],
        "year": "2013",
        "month": "12",
        "day": "07",
        "issue": "2013-12-07",
        "id": "209"
    },
    "208": {
        "host": "https:\/\/s3-ap-southeast-1.amazonaws.com\/production-source\/ChangSha\/2013\/12\/06\/0\/0\/A\/Content\/",
        "timestamp": 1386255815,
        "cover": ["15\/Pg015.png",
        "16\/Pg016.png",
        "1\/Pg001.png",
        "2\/Pg002.png"],
        "year": "2013",
        "month": "12",
        "day": "06",
        "issue": "2013-12-06",
        "id": "208"
    }
}

......

不正确的顺序（当我创建 JsonObject 时）

{
"211": {
    "id": "211",
    "timestamp": 1386514507,
    "cover": ["15\/Pg015.png",
    "16\/Pg016.png",
    "1\/Pg001.png",
    "2\/Pg002.png"],
    "host": "https:\/\/s3-ap-southeast-1.amazonaws.com\/production-source\/ChangSha\/2013\/12\/09\/0\/0\/A\/Content\/",
    "issue": "2013-12-09",
    "month": "12",
    "year": "2013",
    "day": "09"
},
"210": {
    "id": "210",
    "timestamp": 1386415087,
    "cover": ["1\/Pg001.png",
    "2\/Pg002.png",
    "3\/Pg003.png",
    "4\/Pg004.png"],
    "host": "https:\/\/s3-ap-southeast-1.amazonaws.com\/production-source\/ChangSha\/2013\/12\/08\/0\/0\/A\/Content\/",
    "issue": "2013-12-08",
    "month": "12",
    "year": "2013",
    "day": "08"
},
"195": {
    "id": "195",
    "timestamp": 1385115154,
    "cover": ["1\/Pg001.png",
    "2\/Pg002.png",
    "3\/Pg003.png",
    "4\/Pg004.png"],
    "host": "https:\/\/s3-ap-southeast-1.amazonaws.com\/production-source\/ChangSha\/2013\/11\/23\/0\/0\/A\/Content\/",
    "issue": "2013-11-23",
    "month": "11",
    "year": "2013",
    "day": "23"
},
"194": {
    "id": "194",
    "timestamp": 1385048906,
    "cover": ["1\/Pg001.png",
    "2\/Pg002.png",
    "3\/Pg003.png",
    "4\/Pg004.png"],
    "host": "https:\/\/s3-ap-southeast-1.amazonaws.com\/production-source\/ChangSha\/2013\/11\/22\/0\/0\/A\/Content\/",
    "issue": "2013-11-22",
    "month": "11",
    "year": "2013",
    "day": "22"
},
"197": {
    "id": "197",
    "timestamp": 1385306370,
    "cover": ["1\/Pg001.png",
    "2\/Pg002.png",
    "3\/Pg003.png",
    "4\/Pg004.png"],
    "host": "https:\/\/s3-ap-southeast-1.amazonaws.com\/production-source\/ChangSha\/2013\/11\/25\/0\/0\/A\/Content\/",
    "issue": "2013-11-25",
    "month": "11",
    "year": "2013",
    "day": "25"
}
}

.....

我现在的 jsonObject 顺序不正确。如何以正确的顺序创建一个新的 json 对象？谢谢

【问题讨论】：

标签： android json performance

【解决方案1】：

JSON 对象没有顺序，它只是一张地图。即使你在文件中按照想要的顺序编写 JSON，一旦再次加载，它也不会有任何顺序的概念。

如果要排序，则必须使用数组：

[
  {
    "id": "211",
    ...
  },
  {
    "id": "210",
    ...
  },
  ...
]

【讨论】：

谢谢，我决定把json字段放到一个对象中，一个json对象一个java对象，放到arraylist
使用自定义比较器：Collections.sort(objList, new Comparator<Object>() { @Override public int compare(Object arg0, Object arg1) { return a1.getId().compareToIgnoreCase(a2.getId()); } });

【解决方案2】：

您可以相应地使类具有可比性（在您的情况下基于 id），然后可以调用 Collections.sort(/从 Json 文件中提取的对象列表/)；

【讨论】：

谢谢，我决定把json字段放到一个对象中，一个json对象一个java对象，放到arraylist
是的，就像我说的，当你定义类时，让它实现可比较的接口，并根据对象的 Id 覆盖 compareTo(Object another) 方法。然后当你有对象的数组列表时，调用 Collections.sort(/*your arraylist*/);