Android 当多次调用带解析器的AsyncTask时，com.google.gson.JsonSyntaxException

我使用AsyncTask从后端服务器检索数据，并使用gson解析器对其进行解析。当我多次执行AsyncTask时，我会得到com.google.gson.JsonSyntaxException

这是我的异步解析器

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提前感谢。

您误用了对AsyncTask类的调用，必须实例化该类，然后定义参数，连接并最终获取JSON对象。最后记住使用motodoonpostExecute（）作为输出。你不可以

result = new ParseTask().execute(url).get();

您必须执行以下操作。这个代码对我来说很好用

private class GetArticulosParam extends AsyncTask<String, Void, Void> {
    public GetArticulosParam() {
        contactList = new ArrayList<HashMap<String, String>>();
    }
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Showing progress dialog
        pDialog = new ProgressDialog(MainActivity.this);
        pDialog.setMessage("Por Favor, Espere...");
        pDialog.setCancelable(true);
        pDialog.show();
    }
    @Override
    protected Void doInBackground(String... arg0) {

        // String
        // url1="http://pracsysonline.dyndns.org/ListaArticulos/consultaParam.php";
        String url1 = "http://"+direccion+"/ListaArticulos/consultaParam.php";
        String param = arg0[0];
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("param", param));
        // Creating service handler class instance
        ServiceHandler sh = new ServiceHandler();
        // Making a request to url and getting response
        String jsonStr =sh.makeServiceCall(url1,ServiceHandler.POST,params);
        Log.d("Response: ", "> " + jsonStr);
        if (jsonStr != null) {
            try {
                // Getting JSON Array node
                contacts = new JSONArray(jsonStr);
                // looping through All Contacts
                for (int i = 0; i < contacts.length(); i++) {
                    JSONObject c = contacts.getJSONObject(i);
                    String id = c.getString(TAG_DESC);
                    String name = c.getString(TAG_CODE);

                    HashMap<String, String> contact = new HashMap<String, String>();

                    Log.e("PRUEBA", img);
                    // adding each child node to HashMap key => value
                    contact.put(TAG_DESC, id);
                    contact.put(TAG_CODE, name);
                    contactList.add(contact);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        } else {
            Log.e("ServiceHandler", "Couldn't get any data from the url");
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        miAdapter = new ListViewAdapter(MainActivity.this, contactList);
        setListAdapter(miAdapter);
        pDialog.dismiss();
    }
}

私有类GetArticulosParam扩展异步任务{
公共药物{
contactList=新的ArrayList（）；
}
@凌驾
受保护的void onPreExecute（）{
super.onPreExecute（）；
//显示进度对话框
pDialog=新建进度对话框（MainActivity.this）；
pDialog.setMessage（“Por-Favor，Espere…”）；
pDialog.setCancelable（真）；
pDialog.show（）；
}
@凌驾
受保护的Void doInBackground（字符串…arg0）{
//串
//url1=”http://pracsysonline.dyndns.org/ListaArticulos/consultaParam.php";
字符串url1=“http://“+direccion+”/ListaArticulos/consultaParam.php”；
字符串参数=arg0[0]；
List params=new ArrayList（）；
参数添加（新的BasicNameValuePair（“参数”，参数））；
//创建服务处理程序类实例
ServiceHandler sh=新的ServiceHandler（）；
//向url发出请求并获得响应
字符串jsonStr=sh.makeServiceCall（url1，ServiceHandler.POST，params）；
Log.d（“响应：”、“>”+jsonStr）；
if（jsonStr！=null）{
试一试{
//获取JSON数组节点
联系人=新的JSONArray（jsonStr）；
//通过所有触点循环
对于（int i=0；ivalue
联系人：put（标签描述，id）；
联系人：put（标签号、姓名）；
联系人列表。添加（联系人）；
}
}捕获（JSONException e）{
e、 printStackTrace（）；
}
}否则{
Log.e（“ServiceHandler”，“无法从url获取任何数据”）；
}
返回null；
}
@凌驾
受保护的void onPostExecute（void结果）{
super.onPostExecute（结果）；
miAdapter=新的ListViewAdapter（MainActivity.this，contactList）；
setListAdapter（miAdapter）；
pDialog.disclose（）；
}
}

然后是ServiceHandler类

public class ServiceHandler {

static String response = null;
public final static int GET = 1;
public final static int POST = 2;

public ServiceHandler() {

}

/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * */
public String makeServiceCall(String url, int method) {
    return this.makeServiceCall(url, method, null);
}

/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * @params - http request params
 * */
public String makeServiceCall(String url, int method,
        List<NameValuePair> params) {
    try {
        // http client
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpEntity httpEntity = null;
        HttpResponse httpResponse = null;

        // Checking http request method type
        if (method == POST) {
            HttpPost httpPost = new HttpPost(url);
            // adding post params
            if (params != null) {
                UrlEncodedFormEntity encodedEntity = new UrlEncodedFormEntity(params,"UTF-8");
                encodedEntity.setContentEncoding(HTTP.UTF_8);
                httpPost.setEntity(encodedEntity);
                //httpPost.setEntity(new UrlEncodedFormEntity(params,"UTF-8"));
            }

            httpResponse = httpClient.execute(httpPost);

        } else if (method == GET) {
            // appending params to url
            if (params != null) {
                String paramString = URLEncodedUtils
                        .format(params, "utf-8");
                url += "?" + paramString;
            }
            HttpGet httpGet = new HttpGet(url);

            httpResponse = httpClient.execute(httpGet);

        }
        //codigo pruebna
        response = new Scanner(httpResponse.getEntity().getContent(),"UTF-8").useDelimiter("\\A").next();
        /*httpEntity = httpResponse.getEntity();
        response = EntityUtils.toString(httpEntity,"utf-8");*/

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

    return response;

}

公共类ServiceHandler{
静态字符串响应=null；
公共最终静态int GET=1；
公共最终静态int POST=2；
公共服务处理程序（）{
}
/*
*拨打服务电话
*@url-发出请求的url
*@method-http请求方法
* */
公共字符串makeServiceCall（字符串url，int方法）{
返回此.makeServiceCall（url，方法，null）；
}
/*
*拨打服务电话
*@url-发出请求的url
*@method-http请求方法
*@params-http请求参数
* */
公共字符串makeServiceCall（字符串url，int方法，
列表参数）{
试一试{
//http客户端
DefaultHttpClient httpClient=新的DefaultHttpClient（）；
HttpEntity HttpEntity=null；
HttpResponse HttpResponse=null；
//检查http请求方法类型
if（方法==POST）{
HttpPost HttpPost=新的HttpPost（url）；
//添加post参数
如果（参数！=null）{
UrlEncodedFormEntity encodedEntity=新的UrlEncodedFormEntity（参数，“UTF-8”）；
setContentEncoding（HTTP.UTF_8）；
httpPost.setEntity（编码身份）；
//setEntity（新的UrlEncodedFormEntity（参数，“UTF-8”）；
}
httpResponse=httpClient.execute（httpPost）；
}else if（方法==GET）{
//将参数附加到url
如果（参数！=null）{
String paramString=URLEncodedUtils
.格式（参数“utf-8”）；
url+=“？”+参数字符串；
}
HttpGet HttpGet=新的HttpGet（url）；
httpResponse=httpClient.execute（httpGet）；
}
//科迪戈·普鲁布纳
response=new Scanner（httpResponse.getEntity（）.getContent（），“UTF-8”）.useDelimiter（“\\A”）.next（）；
/*httpEntity=httpResponse.getEntity（）；
响应=EntityUtils.toString（httpEntity，“utf-8”）*/
}捕获（不支持的编码异常e）{
e、 printStackTrace（）；
}捕获（客户端协议例外e）{
e、 printStackTrace（）；
}捕获（IOE异常）{
e、 printStackTrace（）；
}
返回响应；
}

---

}

如果错误使用了对AsyncTask类的调用，则必须实例化该类，然后定义参数，连接并最终获取JSON对象。最后记住使用motodoonpostExecute（）作为输出。你不可以

result = new ParseTask().execute(url).get();

您必须执行以下操作。这个代码对我来说很好用

private class GetArticulosParam extends AsyncTask<String, Void, Void> {
    public GetArticulosParam() {
        contactList = new ArrayList<HashMap<String, String>>();
    }
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Showing progress dialog
        pDialog = new ProgressDialog(MainActivity.this);
        pDialog.setMessage("Por Favor, Espere...");
        pDialog.setCancelable(true);
        pDialog.show();
    }
    @Override
    protected Void doInBackground(String... arg0) {

        // String
        // url1="http://pracsysonline.dyndns.org/ListaArticulos/consultaParam.php";
        String url1 = "http://"+direccion+"/ListaArticulos/consultaParam.php";
        String param = arg0[0];
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("param", param));
        // Creating service handler class instance
        ServiceHandler sh = new ServiceHandler();
        // Making a request to url and getting response
        String jsonStr =sh.makeServiceCall(url1,ServiceHandler.POST,params);
        Log.d("Response: ", "> " + jsonStr);
        if (jsonStr != null) {
            try {
                // Getting JSON Array node
                contacts = new JSONArray(jsonStr);
                // looping through All Contacts
                for (int i = 0; i < contacts.length(); i++) {
                    JSONObject c = contacts.getJSONObject(i);
                    String id = c.getString(TAG_DESC);
                    String name = c.getString(TAG_CODE);

                    HashMap<String, String> contact = new HashMap<String, String>();

                    Log.e("PRUEBA", img);
                    // adding each child node to HashMap key => value
                    contact.put(TAG_DESC, id);
                    contact.put(TAG_CODE, name);
                    contactList.add(contact);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        } else {
            Log.e("ServiceHandler", "Couldn't get any data from the url");
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        miAdapter = new ListViewAdapter(MainActivity.this, contactList);
        setListAdapter(miAdapter);
        pDialog.dismiss();
    }
}

私有类GetArticulosParam扩展异步任务{
公共药物{
contactList=新的ArrayList（）；
}
@凌驾
受保护的void onPreExecute（）{
super.onPreExecute（）；
//显示进度对话框
pDialog=新建进度对话框（MainActivity.this）；
pDialog.setMessage（“Por-Favor，Espere…”）；
pDialog.setCancelable（真）；
pDialog.show（）；
}
@凌驾
受保护的Void doInBackground（字符串…arg0）{
//串
//url1=”http://pracsysonline.dyndns.org/ListaArti
public class ServiceHandler {

static String response = null;
public final static int GET = 1;
public final static int POST = 2;

public ServiceHandler() {

}

/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * */
public String makeServiceCall(String url, int method) {
    return this.makeServiceCall(url, method, null);
}

/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * @params - http request params
 * */
public String makeServiceCall(String url, int method,
        List<NameValuePair> params) {
    try {
        // http client
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpEntity httpEntity = null;
        HttpResponse httpResponse = null;

        // Checking http request method type
        if (method == POST) {
            HttpPost httpPost = new HttpPost(url);
            // adding post params
            if (params != null) {
                UrlEncodedFormEntity encodedEntity = new UrlEncodedFormEntity(params,"UTF-8");
                encodedEntity.setContentEncoding(HTTP.UTF_8);
                httpPost.setEntity(encodedEntity);
                //httpPost.setEntity(new UrlEncodedFormEntity(params,"UTF-8"));
            }

            httpResponse = httpClient.execute(httpPost);

        } else if (method == GET) {
            // appending params to url
            if (params != null) {
                String paramString = URLEncodedUtils
                        .format(params, "utf-8");
                url += "?" + paramString;
            }
            HttpGet httpGet = new HttpGet(url);

            httpResponse = httpClient.execute(httpGet);

        }
        //codigo pruebna
        response = new Scanner(httpResponse.getEntity().getContent(),"UTF-8").useDelimiter("\\A").next();
        /*httpEntity = httpResponse.getEntity();
        response = EntityUtils.toString(httpEntity,"utf-8");*/

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

    return response;

}

protected void onPostExecute(JsonObject json) {
super.onPostExecute(json);
result=json;