java.lang.NullPointerException: попытка вызвать виртуальный метод

Question

Я пытаюсь создать функцию входа в систему с регистрацией и логином mysql, но мое приложение падает каждый раз. Я не могу найти проблему!

Это код учебника, и я скорректировал его в соответствии с моими потребностями.

Вот Logcat:

08-23 18:59:43.828 7756-7756/com.example.boss.partyradarvol4 I/art﹕ Late-enabling -Xcheck:jni   
08-23 18:59:43.933 7756-7774/com.example.boss.partyradarvol4 D/OpenGLRenderer﹕ Render dirty regions requested: true 
08-23 18:59:43.942 7756-7756/com.example.boss.partyradarvol4 D/﹕ HostConnection::get() New Host Connection established 0xabc785e0, tid 7756 
08-23 18:59:43.974 7756-7756/com.example.boss.partyradarvol4 D/Atlas﹕ Validating map... 
08-23 18:59:44.239 7756-7774/com.example.boss.partyradarvol4 D/libEGL﹕ loaded /system/lib/egl/libEGL_emulation.so 
08-23 18:59:44.240 7756-7774/com.example.boss.partyradarvol4 D/libEGL﹕ loaded /system/lib/egl/libGLESv1_CM_emulation.so 
08-23 18:59:44.251 7756-7774/com.example.boss.partyradarvol4 D/libEGL﹕ loaded /system/lib/egl/libGLESv2_emulation.so 
08-23 18:59:44.260 7756-7774/com.example.boss.partyradarvol4 D/﹕ HostConnection::get() New Host Connection established 0xa3316120, tid 7774 
08-23 18:59:44.297 7756-7774/com.example.boss.partyradarvol4 I/OpenGLRenderer﹕ Initialized EGL, version 1.4 
08-23 18:59:44.332 7756-7774/com.example.boss.partyradarvol4 D/OpenGLRenderer﹕ Enabling debug mode 0 
08-23 18:59:44.352 7756-7774/com.example.boss.partyradarvol4 W/EGL_emulation﹕ eglSurfaceAttrib not implemented 
08-23 18:59:44.352 7756-7774/com.example.boss.partyradarvol4 W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa33192c0, error=EGL_SUCCESS 
08-23 18:59:49.134 7756-7774/com.example.boss.partyradarvol4 W/EGL_emulation﹕ eglSurfaceAttrib not implemented 
08-23 18:59:49.135 7756-7774/com.example.boss.partyradarvol4 W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xabcff960, error=EGL_SUCCESS 
08-23 18:59:53.490 7756-7817/com.example.boss.partyradarvol4 D/Anfrage﹕ startet 
08-23 18:59:53.492 7756-7817/com.example.boss.partyradarvol4 E/Buffer Error﹕ Error converting result java.lang.NullPointerException: lock == null 
08-23 18:59:53.492 7756-7817/com.example.boss.partyradarvol4 E/JSON Parser﹕ Error parsing data org.json.JSONException: End of input at character 0 of 
08-23 18:59:53.517 7756-7817/com.example.boss.partyradarvol4 E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #5 
    Process: com.example.boss.partyradarvol4, PID: 7756 
    java.lang.RuntimeException: An error occured while executing doInBackground() 
      at android.os.AsyncTask$3.done(AsyncTask.java:300) 
      at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355) 
      at java.util.concurrent.FutureTask.setException(FutureTask.java:222) 
      at java.util.concurrent.FutureTask.run(FutureTask.java:242) 
      at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
      at java.lang.Thread.run(Thread.java:818) 
    Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String org.json.JSONObject.toString()' on a null object reference 
      at com.example.boss.partyradarvol4.Login.Register$CreatUser.doInBackground(Register.java:92) 
      at com.example.boss.partyradarvol4.Login.Register$CreatUser.doInBackground(Register.java:62) 
      at android.os.AsyncTask$2.call(AsyncTask.java:288) 
      at java.util.concurrent.FutureTask.run(FutureTask.java:237) 
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
            at java.lang.Thread.run(Thread.java:818) 
08-23 18:59:53.576 7756-7774/com.example.boss.partyradarvol4 W/EGL_emulation﹕ eglSurfaceAttrib not implemented 
08-23 18:59:53.577 7756-7774/com.example.boss.partyradarvol4 W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xabcff540, error=EGL_SUCCESS 
08-23 18:59:54.094 7756-7778/com.example.boss.partyradarvol4 D/Anfrage﹕ startet 
08-23 18:59:54.094 7756-7778/com.example.boss.partyradarvol4 E/Buffer Error﹕ Error converting result java.lang.NullPointerException: lock == null 
08-23 18:59:54.094 7756-7778/com.example.boss.partyradarvol4 E/JSON Parser﹕ Error parsing data org.json.JSONException: End of input at character 0 of 
08-23 18:59:54.095 7756-7778/com.example.boss.partyradarvol4 I/Process﹕ Sending signal. PID: 7756 SIG: 9 

Register.java:

import android.app.Activity; 
import android.app.ProgressDialog; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.Toast; 

import com.example.boss.partyradarvol4.R; 
import com.example.boss.partyradarvol4.SupportKlassen.JSONEncorder; 

import org.apache.http.NameValuePair; 
import org.apache.http.message.BasicNameValuePair; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.util.ArrayList; 
import java.util.List; 

public class Register extends Activity implements View.OnClickListener{ 

    private EditText eUsername, ePasswort; 
    private Button bRegestrieren; 

    private ProgressDialog pDialog; 

    //Encoder 
    JSONEncorder jsonEncorder = new JSONEncorder(); 

    // Verbindung zum Server 
    private static final String Reg_URL = "http://127.0.0.1:80/webservice/login.php"; 

    private static final String TAG_SUCCESS = "success"; 
    private static final String TAG_MESSAGE = "message"; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.register_); 

     // Editfelder 
     eUsername = (EditText)findViewById(R.id.FELD_Reg_username); 
     ePasswort = (EditText)findViewById(R.id.FELD_Reg_passwort); 

     bRegestrieren = (Button)findViewById(R.id.BUTTON_Reg_regestrieren); 
     bRegestrieren.setOnClickListener(this); 
    } 

    @Override 
    public void onClick(View v) { 
     new CreatUser().execute(); 
    } 

    class CreatUser extends AsyncTask<String,String,String>{ 

     @Override 
     protected void onPreExecute() { 
      super.onPreExecute(); 
      super.onPreExecute(); 
      pDialog = new ProgressDialog(Register.this); 
      pDialog.setMessage("erstelle user..."); 
      //unbestimmt 
      pDialog.setIndeterminate(false); 
      pDialog.setCancelable(true); 
      pDialog.show(); 
     } 

     @Override 
     protected String doInBackground(String... params) { 

      int success; 
      String username = eUsername.getText().toString(); 
      String passwort = ePasswort.getText().toString(); 

      try { 
       List<NameValuePair> parameter = new ArrayList<NameValuePair>(); 
       parameter.add(new BasicNameValuePair("username", username)); 
       parameter.add(new BasicNameValuePair("password", passwort)); 

       Log.d("Anfrage", "startet"); 

       JSONObject json = jsonEncorder.makeHttpRequest(Reg_URL, null ,parameter); 

       Log.d("Restrierung vorbreitet", json.toString()); 

       success = json.getInt(TAG_SUCCESS); 
       if(success == 1){ 
        Log.d("User erstellt", json.toString()); 
        finish(); 
        return json.getString(TAG_MESSAGE); 
       } else { 
        Log.d("Registrierung fehlgeschlagen!", json.getString(TAG_MESSAGE)); 
        return json.getString(TAG_MESSAGE); 
       } 
      } catch (JSONException e) { 
       e.printStackTrace(); 
      } 
      return null; 
     } 

     @Override 
     protected void onPostExecute(String file_url) { 
      pDialog.dismiss(); 
      if(file_url != null){ 
       Toast.makeText(Register.this, file_url, Toast.LENGTH_LONG).show(); 
      } 
     } 
    } 
} 

Answer 1

Это неудачу на что-нибудь, что это это делает:

JSONObject json = jsonEncorder.makeHttpRequest(Reg_URL, null ,parameter); 

Log.d("Restrierung vorbreitet", json.toString()); 

Что вам нужно do предоставляет условия ifnull. Поэтому, если они когда-либо были нулевыми, вы можете решить ничего не делать или присвоить значение по умолчанию

Answer 2

Похоже, что ваш JSONObject json имеет значение null. Это происходит, когда вы вызываете json.toString() в своем операторе журнала прямо под ним.