Android数据传输与Json问题

Question

This is my json array creating with php. I want to know bellow json array have correct syntax. How to get the values withing android,because my sample code get some errors.

THIS IS PHP SCRIPT FOR JSON ARRAY GENARATING

public static function getCategory($_lgtime) {
        $con = JsonDataManip::connect();
        $stmt = $con->prepare("select * from " . _TABLE_CATEGORY . " where lgtime > ?");
        $stmt->execute(array($_lgtime));
        while ($row = $stmt->fetch()) {
            $jsonArray['key'] = $row['key'];
            $jsonArray['name'] = $row['name'];
            $jsonArray['lgtime'] = $row['lgtime'];
            $json[] = $jsonArray;
        }
        return $json;
    }

usage php :

echo json_encode(JsonDataManip::getCategory('20140129184514895'));

GENARATED JSON ARRAY

[{
    "key":"1",
    "name":"Category 10",
    "lgtime":"20140129184514896"
    },
    {
    "key":"2",
    "name":"Category 9",
    "lgtime":"20140129184514896"
    },
    {
    "key":"3",
    "name":"Category 8",
    "lgtime":"20140129184514896"
    }]

ANDROID JSON PARSER FUNCTION

protected Void doInBackground(Void... arg0) {
            ServiceHandler sh = new ServiceHandler();
            String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
            Log.d("Response: ", "> " + jsonStr);
            if (jsonStr != null) {
                try {

                    JSONObject  jsnArry = new JSONObject(jsonStr);
                JSONArray jsonArray = jsnArry.getJSONArray("");
                for(int i=0;i<jsnArry.length();i++){
                    Log.d("JSON PARSE",jsonArray.getJSONObject(i).getString("name"));
                    //contactList[i] =          
                }
                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            return null;
        }

ERROR

01-30 08:45:53.527: W/System.err(1507): org.json.JSONException: Value {"lgtime":"20140129184514896","key":"1","name":"Category 10"} at 0 of type org.json.JSONObject cannot be converted to JSONArray

Answer 1

To check if your JSON string is valid, please use this link JSONLint . As far your error is concerned for your code, it clearly states that

type org.json.JSONObject cannot be converted to JSONArray

Possible Solution (if you are using Gson)

Your response from ServiceHandler would be a string. So convert that into a JSONObject and the pass that to JSONArray .

Example

JSONObject jsonObject = new JSONObject(<responseString>);
JSONArray jsonArray = jsonObject.getJSONArray();

Else

JSONObject jsonObject = new JSONObject(<responseString>);
String key = jsonObject.getJSONObject("key");
String name = jsonObject.getJSONObject("name");
String lgtime = jsonObject.getJSONObject("lgtime");

Then you can continue with your logic in the program.

Answer 2

{    "employees":[
    {
    "firstName":"John",
    "lastName":"Doe"
    },
    {
    "firstName":"Anna",
    "lastName":"Smith"
    },
    {
    "firstName":"Peter",
    "lastName":"Jones"
    }
    ]
}

Your opening and closing braces are missing. that is not a valid json array, The above is a sample array format

Answer 3

Your PHP script returns a JSON array, not a JSON object. You should update your Android code like so:

if (jsonStr != null) {
    try {
        JSONArray json = new JSONArray(jsonStr);
        for (int i=0; i < json.length(); i++) {
            Log.d("JSON PARSE", json.getJSONObject(i).getString("name"));
        }
    } catch (JSONException e) {
        Log.w("JSON PARSE", "Failed to parse JSON!", e);
    }
}