在 Fragment 中获取 JSON 数据时连接到服务器时出错

Question

我正在尝试使用片段中的以下代码从 php 文件中获取 JSON 数据，但每次运行代码时，系统总是返回在 result=false 时调用的 Toast，表明未获取数据。导致数据提取失败的问题可能是什么？

这是包含 JSON 数据的 inded.php 文件的代码。

<?php
$arr = array ( "properties"    =>   array(
            array(
                "companyName"   =>  "Motorola",
                "name" => "Moto"
            ),
            array(
                "companyName" => "Sony",
                "name" => "xPeria"
            ),
            array(
                "companyName" => "Infinix",
                "name" => "S2 Pro"
            )
        )
);

echo json_encode($arr);
?>

下面是片段的onCreateView() 部分中的代码。

    new JSONAsynTask().execute("http://buvick-group.com/app/index.php");

下面是我的JSONAsynTask() 课程的代码。

class JSONAsynTask extends AsyncTask<String, Void, Boolean> {
    String result;
    ProgressDialog dialog;


    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        dialog = new ProgressDialog(getActivity());
        dialog.setMessage("Loading, please wait");
        dialog.setTitle("Connecting server");
        dialog.show();
        dialog.setCancelable(false);
    }

    @Override
    protected Boolean doInBackground(String... urls) {


        try {


            HttpGet httppost = new HttpGet(urls[0]);
            HttpClient httpclient = new DefaultHttpClient();
            HttpResponse response = httpclient.execute(httppost);


            int status = response.getStatusLine().getStatusCode();
            Log.e(TAG, "HTTP Internet Result: " + String.valueOf(status));
            if (status == 200) {
                HttpEntity entity = response.getEntity();
                String data = EntityUtils.toString(entity);

                JSONObject jsono = new JSONObject(data);
                JSONArray jarray = jsono.getJSONArray("properties");

                Log.e(TAG, "JSON Result Length: " + String.valueOf(jarray.length()));

                for (int i = 0; i < jarray.length(); i++) {
                    JSONObject object = jarray.getJSONObject(i);

                    Property property = new Property();

                    property.setName(object.getString("companyName"));
                    property.setDescription(object.getString("name"));

                    propertiesList.add(property);
                }
                return true;
            }
        } catch (ParseException e1) {
            e1.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return false;
    }

    protected void onPostExecute(Boolean result) {

        dialog.dismiss();
        adapter.notifyDataSetChanged();
        if(result == false)
            Toast.makeText(getActivity(), "Unable to fetch data from server", Toast.LENGTH_LONG).show();

    }
}

任何帮助将不胜感激。先感谢您。

Answer 1

如果您正在调用https://androidtutorialpoint.com/api/MobileJSONObject.json API，则直接从 JsonObject 解析。

JSONObject object = new JSONObject(data);
Property property = new Property();
property.setName(object.getString("companyName"));
property.setDescription(object.getString("name"));

propertiesList.add(property);

Answer 2

您的 JSON 需要重新设计。这是为您的android json解析代码生成正确json的代码

<?php
$response = array();
$response["code"] = 200;
$response["properties"] = array();

for($i = 0; $i < 6; $i++) {
    $item = array();
    $item["companyName"] = "Company ".$i;
    $item["name"] = "Model ".$i;
    array_push($response["properties"],  $item );

}


echo json_encode($response);

?>

这将打印出来

{
"code":200,
"properties":[
{
"companyName":"Company 0",
"name":"Model 0"
},
{
"companyName":"Company 1",
"name":"Model 1"
},
{
"companyName":"Company 2",
"name":"Model 2"
},
{
"companyName":"Company 3",
"name":"Model 3"
},
{
"companyName":"Company 4",
"name":"Model 4"
},
{
"companyName":"Company 5",
"name":"Model 5"
}
]
}

Answer 3

在@UmangBurman 的大力帮助下，我得以彻底解决问题。问题是 JSON 数据。使用 JSON 数据格式和正确的 JSONAsynTask，我希望这个问题能帮助将来的人在他们的代码中形成基础。我已经更新了问题中的代码以显示调试版本。干杯

Answer 4

在您的 doInBackground 方法的 Try Catch 块之后删除最后一条语句 return false 后尝试运行代码。 它总是返回假。 还要在 ELSE 块中添加 ** return false** .. 所以你的代码如下所示，再试一次

class JSONAsynTask extends AsyncTask<String, Void, Boolean> {
    String result;
    ProgressDialog dialog;


    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        dialog = new ProgressDialog(getActivity());
        dialog.setMessage("Loading, please wait");
        dialog.setTitle("Connecting server");
        dialog.show();
        dialog.setCancelable(false);
    }

    @Override
    protected Boolean doInBackground(String... urls) {


        try {


            HttpGet httppost = new HttpGet(urls[0]);
            HttpClient httpclient = new DefaultHttpClient();
            HttpResponse response = httpclient.execute(httppost);


            int status = response.getStatusLine().getStatusCode();
            if (status == 200) {
                HttpEntity entity = response.getEntity();
                String data = EntityUtils.toString(entity);


                JSONObject jsono = new JSONObject(data);
                JSONArray jarray = jsono.getJSONArray("properties");

                for (int i = 0; i < jarray.length(); i++) {
                    JSONObject object = jarray.getJSONObject(i);

                    Property property = new Property();

                    property.setName(object.getString("companyName"));
                    property.setDescription(object.getString("name"));

                    propertiesList.add(property);
                }
                return true;
            }else{

                return false;
             }



        } catch (ParseException e1) {
            e1.printStackTrace();
            return false;
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        } catch (JSONException e) {
            e.printStackTrace();
            return false;
        }

    }

    protected void onPostExecute(Boolean result) {

        dialog.dismiss();
        adapter.notifyDataSetChanged();
        if(result == false)
            Toast.makeText(getActivity(), "Unable to fetch data from server", Toast.LENGTH_LONG).show();

    }
}