Question

我有一个JSON Parser类，如果传递了一个可选参数，就会发送一个Httppost。

public class JSONParser {

static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {

}

public JSONObject getJSONFromUrl(String url, Object... params) {

    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);

        if(params.length > 0){
            httpPost.setEntity(new UrlEncodedFormEntity((List<? extends NameValuePair>)params[0]));
        }

        HttpResponse httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity = httpResponse.getEntity();
        is = httpEntity.getContent();       


    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;

}

}

这适用于我的ICS和JellyBean设备，但不适用于Froyo和Gingerbread。错误消息是：

10-21 13:49:10.348: E/Buffer Error(471): Error converting result java.lang.NullPointerException
10-21 13:49:10.348: E/JSON Parser(471): Error parsing data org.json.JSONException: End of input at character 0 of

有人可以帮帮我吗？ froyo和gingerbread只支持httpGet ??

Answer 1

首先检查调用此json字符串的文件，以查找将破坏json格式的无效字符。当我从php文件中获取数据时遇到同样的问题，我的php文件发送了一些额外的错误导致解析为jSONObject失败

   try {
    jObj = new JSONObject(json);
    } catch (JSONException e) {
    Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

这就是我在那里遇到错误

Answer 2

当我尝试在ubuntu的Froyo和gingerbread模拟器中测试它时，它很有趣，它可以工作。但是，当我尝试在Windows中执行它时根本不起作用。所以这是正式关闭:)）

Answer 3

尝试将其放入asynctask

例如

private class PermissionEnableAsyncTask extends AsyncTask<String, Void, Object[]>
{
    private ProgressDialog mProgressDialog = null;
    @Override
    protected void onPreExecute() 
    {
        super.onPreExecute();
        mProgressDialog = new ProgressDialog(PermissionList.this);
        mProgressDialog.setMessage(Constant.MSG_PROGRESSBAR_WAITING);
        mProgressDialog.setCancelable(false);
        mProgressDialog.setCanceledOnTouchOutside(false);
        mProgressDialog.show();
    }

    @Override
    protected Object[] doInBackground(String... params) 
    {
        try
        {
            String Url = "your URL";
                    //your logic
        return yourlogic;
        }
        catch(Exception e)
        {
            e.printStackTrace();
            return null;    
        }
    }

    @Override
    protected void onPostExecute(Object[] object)
    {
        super.onPostExecute(object);
        mProgressDialog.dismiss();
        try 
        {
                            your logic          
                    }
        catch(Exception e) 
        {
            e.printStackTrace();
        }
    }
}

json解析器不在froyo和gingerbread中工作，但在ics上工作

3 个答案: