转换 ArrayList<MyCustomClass>到 JSONArray [英] convert ArrayList&lt;MyCustomClass&gt; to JSONArray

问题描述

我有一个 ArrayList，我在一个 ListView 的 ArrayAdapter 中使用它.我需要获取列表中的项目并将它们转换为 JSONArray 以发送到 API.我已经四处搜索，但没有找到任何解释这可能如何工作的内容，任何帮助将不胜感激.

I have an ArrayList that I use within an ArrayAdapter for a ListView. I need to take the items in the list and convert them to a JSONArray to send to an API. I've searched around, but haven't found anything that explains how this might work, any help would be appreciated.

更新 - 解决方案

这是我最终为解决这个问题所做的.

Here is what I ended up doing to solve the issue.

ArrayList 中的对象:

Object in ArrayList:

public class ListItem {
    private long _masterId;
    private String _name;
    private long _category;

    public ListItem(long masterId, String name, long category) {
        _masterId = masterId;
        _name = name;
        _category = category;
    }

    public JSONObject getJSONObject() {
        JSONObject obj = new JSONObject();
        try {
            obj.put("Id", _masterId);
            obj.put("Name", _name);
            obj.put("Category", _category);
        } catch (JSONException e) {
            trace("DefaultListItem.toString JSONException: "+e.getMessage());
        }
        return obj;
    }
}

这是我如何转换它:

ArrayList<ListItem> myCustomList = .... // list filled with objects
JSONArray jsonArray = new JSONArray();
for (int i=0; i < myCustomList.size(); i++) {
        jsonArray.put(myCustomList.get(i).getJSONObject());
}

和输出:

[{"Name":"Name 1","Id":0,"Category":"category 1"},{"Name":"Name 2","Id":1,"Category":"category 2"},{"Name":"Name 3","Id":2,"Category":"category 3"}]

希望有一天这对某人有所帮助！

Hope this helps someone some day!

推荐答案

如果我正确阅读了 JSONArray 构造函数，您可以从任何 Collection(arrayList 是 Collection 的子类)构建它们，如下所示:

If I read the JSONArray constructors correctly, you can build them from any Collection (arrayList is a subclass of Collection) like so:

ArrayList<String> list = new ArrayList<String>();
list.add("foo");
list.add("baar");
JSONArray jsArray = new JSONArray(list);

参考文献:

• jsonarray 构造函数:http://developer.android.com/reference/org/json/JSONArray.html#JSONArray%28java.util.Collection%29
• 集合:http://developer.android.com/reference/java/util/Collection.html

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