Wert Datenbank des Typs java.lang.String kann nicht in JSONObject konvertiert werden

Question

Die mit dem unten stehenden Code angegebenen Daten werden in die Datenbank eingefügt, zeigen jedoch nicht an, ob das Dialogfeld erfolgreich ist oder nicht.

Mein Ziel api ist 23.

Soll ich Gson benutzen?

Bitte helfen.

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

String register_url = "http://192.168.1.101/loginapp/register.php"; 

    Context ctx; 

    Activity activity; 

    ProgressDialog progressDialog; 

    AlertDialog.Builder builder; 

    public BackgroundTask(Context ctx) 
    { 
     this.ctx = ctx; 
     activity = (Activity)ctx; 
    } 

    @Override 
    protected void onPreExecute() { 
     builder = new AlertDialog.Builder(activity); 
     progressDialog = new ProgressDialog(ctx); 
     progressDialog.setTitle("Please wait..."); 
     progressDialog.setMessage("Connecting to server..."); 
     progressDialog.setIndeterminate(true); 
     progressDialog.setCancelable(false); 
     progressDialog.show(); 

     super.onPreExecute(); 
    } 

    @Override 
    protected String doInBackground(String... params) { 
     String method = params[0]; 
     if(method.equals("register")) 
     { 
      try { 
       URL url = new URL(register_url); 
       HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection(); 
       httpURLConnection.setRequestMethod("POST"); 
       httpURLConnection.setDoOutput(true); 
       httpURLConnection.setDoInput(true); 
       OutputStream outputStream = httpURLConnection.getOutputStream(); 
       BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8")); 
       String name = params[1]; 
       String email = params[2]; 
       String password = params[3]; 
       String data = URLEncoder.encode("name", "UTF-8")+"="+URLEncoder.encode(name,"UTF-8")+"&"+ 
         URLEncoder.encode("email","UTF-8")+"="+URLEncoder.encode(email,"UTF-8")+"&"+ 
         URLEncoder.encode("password","UTF-8")+"="+URLEncoder.encode(password,"UTF-8"); 
       bufferedWriter.write(data); 
       bufferedWriter.flush(); 
       bufferedWriter.close(); 
       outputStream.close(); 
       InputStream inputStream = httpURLConnection.getInputStream(); 
       BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); 
       StringBuilder stringBuilder = new StringBuilder(); 
       String line = ""; 
       while((line=bufferedReader.readLine()) != null) 
       { 
        stringBuilder.append(line+"\n"); 
       } 
       httpURLConnection.disconnect(); 
       Thread.sleep(5000); 
       // return string builder as normal string. 
       return stringBuilder.toString(); 

      } catch (MalformedURLException e) { 
       e.printStackTrace(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } catch (InterruptedException e) { 
       e.printStackTrace(); 
      } 
     } 
     return null; 
    } 

    @Override 
    protected void onProgressUpdate(Void... values) { 
     super.onProgressUpdate(values); 
    } 

    @Override 
    protected void onPostExecute(String json) { 
     try { 
      progressDialog.dismiss(); 
      JSONObject jsonObject = new JSONObject(json); 
      //need to get json array from json object. 
      JSONArray jsonArray = jsonObject.getJSONArray("server_response"); 
      //now we can get each of the json data from json array. 
      JSONObject jo = jsonArray.getJSONObject(0); 
      //now we can read each data from json object; 
      String code = jo.getString("code"); 
      String message = jo.getString("message"); 
      if(code.equals("reg_true")) 
      { 
       showDialog("Registration Success..",message,code); 
      } 
      else if(code.equals("reg_false")) 
      { 
       showDialog("Registration failed..",message,code); 
      } 
     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 


    } 

    public void showDialog(String title, String message, String code) 
    { 
      builder.setTitle(title); 
      if(code.equals("reg_true")||code.equals("reg_false")) 
      { 
       builder.setMessage(message); 
       builder.setPositiveButton("OK", new DialogInterface.OnClickListener() { 
        @Override 
        public void onClick(DialogInterface dialog, int which) { 
         dialog.dismiss(); 
         activity.finish(); 
        } 
       }); 
       AlertDialog alertDialog = builder.create(); 
       alertDialog.show(); 

      } 
    } 
} 

Answer 1

Der Rückgabewert von doInBackground() Methode OnPostExecute geben wird(). Innerhalb dieser Methode:

@Override 
    protected String doInBackground(String... params) { 
     String method = params[0]; 
     if(method.equals("register")) 
     { 
      try { 
       URL url = new URL(register_url); 
       HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection(); 
       //.... 
       // return string builder as normal string. 
       return stringBuilder.toString(); 

      } catch (MalformedURLException e) { 
       e.printStackTrace(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } catch (InterruptedException e) { 
       e.printStackTrace(); 
      } 
     } 
     return null;   //YOU ARE RETURNING NULL. CHECK WHETHER params[0] is "register" 
    } 
    //.... 
    @Override 
    protected void onPostExecute(String json) { //json might be null. Try to print it using log.debug() 
     try { 
      progressDialog.dismiss(); 
      JSONObject jsonObject = new JSONObject(json); //This might throw exception 
      //... 
     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 
    } 

das Protokoll in Pastebin einfügen und hier einen Link anhängen. Und auch sehen: String cannot be converted to JSONObject exception