为什么我不能创建JSON对象？

Question

I'm using HTTP Get to retrieve a JSON formatted String from my website.

However, when I try to create the JSONObject, nothing happens. The object isn't created and I can't acces Arrays or anything inside it.

I've checked that my app does get the right String and it is correctly formatted as a JSON.

Do I have to declare it in some particular way or have separate try/catch blocks...?

I'm at my wits end with this, so any help would be most appreciated...

Lower you have all the code I've written in this issue and although it's not much, I'm stuck and don't know where to go with this...

public String result, testString;
public TextView resultText; 
public String url = "http://www.ace.ucv.ro/android/android.php";

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mainmenu);

    resultText = (TextView) findViewById(R.id.result);

    try {
        HttpGet httpGet = new HttpGet(url);

        result = EntityUtils.toString(new DefaultHttpClient().execute(httpGet).getEntity());

        JSONObject jsonObject = new JSONObject(result);

    } catch (ParseException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (JSONException e) {
        e.printStackTrace();
    }           
    resultText.setText(result);

}

Answer 1

The URL you have in code (http://www.ace.ucv.ro/android/android.php) does not return Json object, instead it is a JSONArray.

Just replace JSONObject with JSONArray and you'll be fine.

Answer 2

Are you sure that the string stored in result is just a JSONObject, or is it a JSONArray?

I remember stumbling on a similar problem.

Answer 3

At first glance, your code looks familiar / reasonable. But perhaps you should un-nest it and log the intermediate results - which would help you see which stage is going wrong. For example...

HttpGet httpGet = new HttpGet(url);
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpResponse response = httpClient.execute(httpGet);
Log.v("test", "HTTP response = " + response);
HttpEntity entity = response.getEntity();
Log.v("test", "HTTP entity = " + entity);
String content = EntityUtils.toString(entity);
Log.v("test", "HTTP content = " + content);
JSONObject mJsonObj = new JSONObject(mContent);