Question

我一直致力于Android项目，我希望在其中显示存储在数据库中的所有数据。我已经完成了那部分，但问题是我能够从 localhost 获取数据但是当我移动到托管服务器时它不是给我任何数据。我已连接到服务器并且能够访问特定的php文件，但它返回一个空的JSON字符串，其中包含数据。

这是我的连接类：

public class Connecter {

public static HttpURLConnection connect (String urlAddress){

    try {
        URL  url = new URL(urlAddress);
        HttpURLConnection con = (HttpURLConnection) url.openConnection();

        ///////Setting properties to con object
        con.setRequestMethod("POST");
        con.setConnectTimeout(20000);
        con.setReadTimeout(20000);

        con.setDoInput(true);
        con.setDoOutput(true);
        ////////Returning the Con object
        return con;


    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    return null;
    }
}

我使用其他课程发帖。这是我用来传递特定php文件的URL的过程：

String address2 = "http://www.tutorshubbd.com/android/allTeacher.php";
    Log.d(TAG," .............///..........Primary Data Display ");
    String query = "";
    SendGetAllTeachers sg2 = new SendGetAllTeachers(ActivityTeacher.this,address2,query,listViewTeachers,ivNoData,ivNoInternet);
    sg2.execute();

以下是我使用的特定php文件：

＆＃13;

<?php


$host ='tutorshubbd.com';
$username = 'cpanel_username';
$pwd = 'cpanel_password';
$db = 'tutorshu_db';

$con = mysqli_connect($host, $username, $pwd, $db) or die('Unable to connect');

if (mysqli_connect_error($con)) {
	echo "Failed to connect to the DataBase".mysqli_connect_error();

}

$name = $_POST['Query'];


$sql = "SELECT * FROM Teacher WHERE Name LIKE '%$name%'";

$query = mysqli_query($con, $sql);

if ($query) {
	while ($row = mysqli_fetch_array($query)) {
		$data[] = $row;
	}
	print(json_encode($data));

}else{
	echo "Not Found!";
}
mysqli_close($con);

?>

＆＃13;

以下是我发布和提取数据的其他代码。（我在使用此代码从localhost获取数据时没有遇到任何问题，但这样做只是因为如果您需要查看它以找出问题）。

public class SendGetAllTeachers extends AsyncTask<Void,Void,String> {

private static final String TAG ="ActivityTeacher";
private Context context;
private String urlAddress;
private String query;
private ListView listView;
private ImageView imageViewNoData, imageViewNoSignal;
private ProgressDialog progressDialog;

public SendGetAllTeachers(Context context, String urlAddress, String query, ListView listView, ImageView...imageViews) {
    this.context = context;
    this.urlAddress = urlAddress;
    this.query = query;
    this.listView = listView;

    this.imageViewNoData=imageViews[0];
    this.imageViewNoSignal=imageViews[1];
}

@Override
protected void onPreExecute() {
    super.onPreExecute();
    progressDialog = new ProgressDialog(context);
    progressDialog.setTitle("Search:");
    progressDialog.setMessage("Searching for Data...");
    progressDialog.show();
}

@Override
protected String doInBackground(Void... params) {
    return this.sendAndReceive();
}


@Override
protected void onPostExecute(String s) {
    super.onPostExecute(s);
    progressDialog.dismiss();

    //RESET LISTVIEW
    listView.setAdapter(null);


    if (s != null){
        if (!s.contains("null")){
            ParserTeacher parserT = new ParserTeacher(context,s,listView);
            parserT.execute();

            imageViewNoData.setVisibility(View.INVISIBLE);
            imageViewNoSignal.setVisibility(View.INVISIBLE);


        }else{
            Log.d(TAG,"......//////////.........///////// Getting Visible ......... NO DATA______AT");
            Toast.makeText(context, "Sorry! No Such Data Exists.", Toast.LENGTH_SHORT).show();
        }

    }else {
        imageViewNoData.setVisibility(View.INVISIBLE);
        Toast.makeText(context, "Sorry! Unable to connect to the server.", Toast.LENGTH_SHORT).show();
        imageViewNoSignal.setVisibility(View.INVISIBLE);
    }

}

private String sendAndReceive(){
    HttpURLConnection con = Connecter.connect(urlAddress);
    if(con == null)
        return null;

    try {
        OutputStream outputStream = con.getOutputStream();
        BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream));
        Log.d(TAG,"......//////////.........///////// WRITING DATA ......... FIRED______");
        bufferedWriter.write(new DataPackager(query).packageData());

        Log.d(TAG,"......//////////.........///////// NOT WORKING___!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
        bufferedWriter.flush();
        //Release Resources.
        bufferedWriter.close();
        outputStream.close();


        //Response Code
        int responseCode = con.getResponseCode();
        //Decoding response code
        if (responseCode == con.HTTP_OK){

            //Return Data
            InputStream inputStream = con.getInputStream();

            //Read the returned data...
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            String line;
            Log.d(TAG,"......//////////.........///////// DATA READ......... FIRED______");
            StringBuffer response = new StringBuffer();

            if (bufferedReader!=null){
                while((line = bufferedReader.readLine())!=null){

                    response.append(line+"\n");
                }

            }else
                return null;
            return response.toString();

        }else
            return String.valueOf(responseCode);




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

    return null;
}

}

////////////////////////////////

public class DataPackager {

String query;

public DataPackager(String query) {
    this.query = query;
}

public String packageData(){

    JSONObject jsonObject = new JSONObject();
    StringBuffer queryStringBuffer = new StringBuffer();

    try {
        jsonObject.put("Query", query);
        Boolean fistValue = true;
        Iterator iterator = jsonObject.keys();

        do {
            String key = iterator.next().toString();
            String value = jsonObject.get(key).toString();

            if (fistValue){
                fistValue = false;
            }else{
                queryStringBuffer.append("&");
            }

            queryStringBuffer.append(URLEncoder.encode(key,"UTF-8"));
            queryStringBuffer.append("=");
            queryStringBuffer.append(URLEncoder.encode(value,"UTF-8"));

        }while (iterator.hasNext());

        return queryStringBuffer.toString();


    } catch (JSONException e) {
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    }

    return null;
}



}

///////////////////////////////

public class ParserTeacher extends AsyncTask<Void,Void,Integer> {
public static final String TAG = "Parser Teacher";

    private Context c;
    private String data;
    private ListView lv;



    List<GetItems> items = new ArrayList<>();




    public ParserTeacher(Context c, String data, ListView lv) {
        this.c = c;
        this.data = data;
        this.lv = lv;
    }


    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected Integer doInBackground(Void... params){
        return this.parse();
    }


    @Override
    protected void onPostExecute(Integer integer) {
        super.onPostExecute(integer);

        if (integer ==1 ){
            ///////BIND TO LIST VIEW...............................
            CustomAdapter adapter = new CustomAdapter(c, items);
            lv.setAdapter(adapter);




            lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

                    GetItems sendItem = items.get(i);

                    String name = sendItem.getName();


                    //Snackbar.make(view,"Teachers Detail Mode",Snackbar.LENGTH_LONG).show();

                    Intent I = new Intent();
                    I.setClass(view.getContext(),TeachersView.class);
                    Bundle extras = new Bundle();
                    extras.putString("Name", name);


                    I.putExtras(extras);
                    view.getContext().startActivity(I);

                }
            });



        }else{
            Log.d(TAG," >>>>>>>>>>>>>>>>>>>>>>>>>>>> Parsing Error!");
            Toast.makeText(c, "Unable to Parse...!", Toast.LENGTH_SHORT).show();


        }




    }


    private int parse(){

        try{
            JSONArray ja = new JSONArray(data);

            //Log.i("tagconvertstr","............................................\n\n"+ "["+ja+"]");
            JSONObject jo = null;
            items.clear();

            GetItems getItems = null;



            for (int i=0; i<ja.length();i++){
                jo=ja.getJSONObject(i);

                String name = jo.getString("Name");



                getItems = new GetItems();

                getItems.setName(name);


                items.add(getItems);

            }

            return 1;

        } catch (JSONException e) {
            Log.d(TAG,"Here is the STACK TRACE.........>>>>>>>>>>>>>>>>>>>>>>>>>>>");
            e.printStackTrace();
        }
        return 0;
    }
    }

（我使用此代码在localhost中获取数据没有问题。）

如果您加载网址，您会看到有很多数据（有时可能需要时间加载），但在应用程序中它返回一个空字符串。我没有使用像排球或翻新这样的任何库。

我已经看到很多关于此的问题，但这与它们略有不同。我能够连接但不能从托管服务器获取，但我能够从本地主机获取。

Answer 1

您的回复标头没有Content-Type值。你必须在打印数据之前添加到你的php代码中。

header('Content-type:application/json;charset=utf-8');

托管服务器未向Android应用提供任何数据

1 个答案: