在 Android 中从 socket.IO 解析 JSONArray

Question

我一直在尝试在 android 中转换 JSON。我从我的 socket.io-server 收到这个作为响应：

 [{
    "_id":"5a4cee2808699d0014d99dfc",
    "conversation_id":"5a4cee2808699d0014d99dfb",
    "message":"text1",
    "author":"5a173c64187e5c335488e906",
    "created_at":"1514991144450",
    "__v":0
},{
    "_id":"5a4cee4208699d0014d99dfd",
    "conversation_id":"5a4cee2808699d0014d99dfb",
    "message":"text2",
    "author":"5a2505c50c1ff300149d799f",
    "created_at":"1514991170944",
    "__v":0
},{
    "_id":"5a4cee8608699d0014d99dfe",
    "conversation_id":"5a4cee2808699d0014d99dfb",
    "message":"text3",
    "author":"5a173c64187e5c335488e906",
    "created_at":"1514991238321",
    "__v":0
},{
    "_id":"5a4ceea908699d0014d99dff",
    "conversation_id":"5a4cee2808699d0014d99dfb",
    "message":"text4",
    "author":"5a2505c50c1ff300149d799f",
    "created_at":"1514991273472",
    "__v":0
},{
    "_id":"5a4ceed508699d0014d99e00",
    "conversation_id":"5a4cee2808699d0014d99dfb",
    "message":"text5",
    "author":"5a173c64187e5c335488e906",
    "created_at":"1514991317353",
    "__v":0
},{
    "_id":"5a4ceef108699d0014d99e01",
    "conversation_id":"5a4cee2808699d0014d99dfb",
    "message":"text6;)",
    "author":"5a2505c50c1ff300149d799f",
    "created_at":"1514991345153",
    "__v":0
},{
    "_id":"5a4cef1c08699d0014d99e02",
    "conversation_id":"5a4cee2808699d0014d99dfb",
    "message":"text7",
    "author":"5a173c64187e5c335488e906",
    "created_at":"1514991388937",
    "__v":0
}]

通常人们会尝试从 socket.io 网站获取这样的 JSONObject：

private Emitter.Listener onNewMessage = new Emitter.Listener() {
@Override
public void call(final Object.. args) {
    getActivity().runOnUiThread(new Runnable() {
        @Override
        public void run() {
            JSONObject data = (JSONObject) args[0];
            String username;
            String message;
            try {
                username = data.getString("username");
                message = data.getString("message");
            } catch (JSONException e) {
                return;
            }

            // add the message to view
            addMessage(username, message);
        }
    });
}

但问题是这是针对一个 JSON 对象的，所以由于我的数据是一个数组，所以这不需要另一种方法吗？

我一直在尝试按照网站所说的传统方式进行操作，但它只是返回：

java.lang.ClassCastException: java.lang.String 无法转换为 org.json.JSONObject

提前感谢您尝试帮助我，我是这种东西的新手！

编辑：

    private Emitter.Listener onConversationJoined = new Emitter.Listener() {
    @Override
    public void call(final Object... args) {
        getActivity().runOnUiThread(new Runnable() {
            @Override
            public void run() {
                String data = args[0].toString();
                Log.e("TestIt", data);
                JSONArray jsonarray;
                try {
                    jsonarray = new JSONArray(args[0]);
                    for (int i=0; i < jsonarray.length(); i++) {
                        JSONObject chatmsg = jsonarray.getJSONObject(i);
                        String conversation_id = chatmsg.getString("conversation_id");
                        String message = chatmsg.getString("message");
                        String author = chatmsg.getString("author");
                        String created_at = chatmsg.getString("created_at");

                        addMessageUser(message);

                        // Whatever you want to do with these fields.

                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });
    }
};

它在 LogCat 中说：

01-03 22:04:53.758 32259-32259/com.app.app.app W/System.err: org.json.JSONException: 不是原始数组：类 java.lang.String

在这一行：

jsonarray = new JSONArray(args[0]);

Answer 1

我通过转换“args[0].toString()”并从中制作一个 JSONArray 来修复它，而不仅仅是 args[0]。

所以，而不是

jsonarray = new JSONArray(args[0]);

我必须这样做：

String data = args[0].toString();
JSONArray jsonarray = new JSONArray(data);

感谢@Barns 让我想到只放入字符串而不是 JSONObject。

Answer 2

请看一下这个 stackoverflow 帖子。你需要使用JSONArray 而不是JSONObject https://stackoverflow.com/a/18977220/2889043