Question

JSON数据：

{
"data": [
 {
   "id": 5,
   "name": "Deal One"
 },
 {
   "id": 6,
   "name": "Deal Two"
 },
 {
   "id": 7,
   "name": "Deal Three"
 }
]
}

onPostExecute，正在投射JSONArray。

    @Override
    protected void onPostExecute(String result) {

        //this method will be running on UI thread
        ArrayList<String> dataList = new ArrayList<String>();
        pdLoading.dismiss();


        if(result.equals("no rows")) {

            // Do some action if no data from database

        }else{

            try {

                JSONArray jArray = new JSONArray(result);

                // Extract data from json and store into ArrayList
                for (int i = 0; i < jArray.length(); i++) {
                    JSONObject json_data = jArray.getJSONObject(i);
                    dataList.add(json_data.getString("name"));
                }

                strArrData = dataList.toArray(new String[dataList.size()]);

            } catch (JSONException e) {
                // You to understand what actually error is and handle it appropriately
                Toast.makeText(MainActivity.this, e.toString(), Toast.LENGTH_LONG).show();
                Toast.makeText(MainActivity.this, result.toString(), Toast.LENGTH_LONG).show();
            }

        }

    }

所有这一切背后的重要思想是什么？在this tutorial之后执行自动填充演出。我注意到他们的JSON看起来与我的非常不同。

如何修复JSONArray错误？

EDIT2

STACKTRACE :( 编辑3 ：当我按照其他人的代码时，会发生以下错误）

01-19 14:41:15.442 6513-6513/gsi.xform W/System.err: org.json.JSONException: Value Connection of type java.lang.String cannot be converted to JSONObject
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at org.json.JSON.typeMismatch(JSON.java:111)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at org.json.JSONObject.<init>(JSONObject.java:160)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at org.json.JSONObject.<init>(JSONObject.java:173)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at gsi.xform.MainActivity$AsyncFetch.onPostExecute(MainActivity.java:385)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at gsi.xform.MainActivity$AsyncFetch.onPostExecute(MainActivity.java:288)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at android.os.AsyncTask.finish(AsyncTask.java:651)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at android.os.AsyncTask.-wrap1(AsyncTask.java)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at android.os.Looper.loop(Looper.java:148)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:5417)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
01-19 14:41:15.448 6513-6513/gsi.xform W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

EDIT4 ：

这是doInBackground代码：

    @Override
    protected String doInBackground(String... params) {
        try {

            // Enter URL address where your php file resides or your JSON file address
            url = new URL("http://myprivate.url?X-Authorization=token");

        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return e.toString();
        }
        try {

            // Setup HttpURLConnection class to send and receive data from php and mysql
            conn = (HttpURLConnection) url.openConnection();
            conn.setReadTimeout(READ_TIMEOUT);
            conn.setConnectTimeout(CONNECTION_TIMEOUT);
            conn.setRequestMethod("GET");

            // setDoOutput to true as we receive data
            conn.setDoOutput(true);
            conn.connect();

        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
            return e1.toString();
        }

        try {

            int response_code = conn.getResponseCode();

            // Check if successful connection made
            if (response_code == HttpURLConnection.HTTP_OK) {

                // Read data sent from server
                InputStream input = conn.getInputStream();
                BufferedReader reader = new BufferedReader(new InputStreamReader(input));
                StringBuilder result = new StringBuilder();
                String line;

                while ((line = reader.readLine()) != null) {
                    result.append(line);
                }

                // Pass data to onPostExecute method
                return (result.toString());

            } else {
                return("Connection error");
            }

        } catch (IOException e) {
            e.printStackTrace();
            return e.toString();
        } finally {
            conn.disconnect();
        }


    }

Answer 1

result是JSONObject而不是JSONArray

   // fetch the object      
    JSONObject obj = new JSONObject(result);

   // fetch the data array
    JSONArray jArray = obj.getJSONArray("data");

    // Extract data from json and store into ArrayList
    for (int i = 0; i < jArray.length(); i++) {
        JSONObject json_data = jArray.getJSONObject(i);
        dataList.add(json_data.getString("name"));
    }

{                     // beginning of JSONObject
"data": [             // nested JSONArray
 {                    // nested JSONObject inside JSONArray
   "id": 5,  
   "name": "Deal One"
 },
 {
   "id": 6,
   "name": "Deal Two"
 },
 {
   "id": 7,
   "name": "Deal Three"
 }
]
}  // ending of JSONObject

信息：另一个问题是Runtime-Permission实施，执行流程意味着在建立互联网连接时没有给出许可。

Answer 2

只是有点小错误在你的JSON中有On Object，有一个名为“data”的数组

  JSONObject obje = new JSONObject(results);
  JSONArray jArray = obje.getJSONArray("data");

然后就像你一样。只记得对象的{}和JSON的数组的[]

Answer 3

您正在将字符串转换为jsonArray，其中您的响应是jsonObject：

这样做：

JSONObject jsnobject = new JSONObject(result);

JSONArray jsonArray = jsnobject.getJSONArray("data");


    for (int i = 0; i < jsonArray.length(); i++)
    {
        JSONObject data= jsonArray.getJSONObject(i);
        dataList.add(data.getString("name"));
    }

org.json.JSONException value类型java.lang.String的连接无法转换为JSONArray

3 个答案: