NullPointerException à sqlite alimenter une listview dans Android

Question

Je possède ce code:

package com.rbrlnx.lugares; 

public class DataBaseHelper extends SQLiteOpenHelper { 

    private static String DB_PATH = "/data/data/com.rbrlnx.lugares/databases/"; 
    private static final String DATABASE_NAME="db.db"; 
    SQLiteDatabase db; 

    String CREATE_TABLE = "CREATE TABLE IF NOT EXISTS lugares (" + 
     "_id INTEGER PRIMARY KEY AUTOINCREMENT, " + 
     "nombre text NOT NULL," + 
     "descripcion text NOL NULL,"+ 
     "latitud real," + 
     "longitud real," + 
     "foto String);"; 

    /*Primero se crea constructor, funcion onCreate, onUpgrade,Abrir y Cerrar*/ 

    public DataBaseHelper(Context context){ 
     super(context,DATABASE_NAME,null,1); 
    } 

    public void onCreate(SQLiteDatabase db){ 
     db.execSQL(CREATE_TABLE); 
    } 

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 

    db.execSQL("DELETE TABLE IF EXITS "+DATABASE_NAME+""); 
    onCreate(db); 
    } 
    public void openDataBase() throws SQLException{ 

     //Open the database 
     String myPath = DB_PATH + DATABASE_NAME; 
     db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE); 

    }  

    public void close(){ 
     db.close(); 
    } 


    /*Despues metodos para añadir y obtener datos*/ 

    public long addNombre(String nombre){ 

    ContentValues cv = new ContentValues(); 
    cv.put("nombre", nombre); 
    return db.insert("lugares", null, cv);   
    } 

     public long addDescripcion(String descripcion){ 

      ContentValues cv = new ContentValues(); 
       cv.put("descripcion", descripcion); 
       return db.insert("lugares", null, cv);   

     } 
     public long addLatitud(double latitud){ 

      ContentValues cv = new ContentValues(); 
       cv.put("latitud", latitud); 
       return db.insert("lugares", null, cv);   

     } 
     public long addLongitud(double longitud){ 

      ContentValues cv = new ContentValues(); 
       cv.put("longitud", longitud); 
       return db.insert("lugares", null, cv);   

     } 

     public long addFoto(String foto) { 

      ContentValues cv = new ContentValues(); 
       cv.put("foto", foto); 
       return db.insert("lugares", null, cv);   

      } 


     public Cursor getNombres(){ 
       Cursor respuesta = db.rawQuery("select nombres from lugares", null); 

       return respuesta; 

      } 
     public long addImagen(Uri directorioimagen){ 

      String imagen = getRealPathFromURI(directorioimagen);   
      ContentValues cv = new ContentValues(); 
      cv.put("foto", imagen); 
      return db.insert("lugares", null, cv);   


     } 







     } 

et ce

public class listatab extends ListActivity{ 

     Context context; 
     ListView listanombres; 
     DataBaseHelper ayudabbdd; 


     public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState);   
     Cursor nombresC; 
     nombresC = ayudabbdd.getNombres(); 
     startManagingCursor(nombresC); 
     ListAdapter adapter = new SimpleCursorAdapter(this, R.layout.listatab, nombresC, new String[] { "nombre" }, new int[] { R.id.lista }); 
     this.setListAdapter(adapter); 
     this.getListView().setTextFilterEnabled(true); 


     } 
     @Override 
    protected void onDestroy() { 
     super.onDestroy(); 
     if (ayudabbdd != null) { 
      ayudabbdd.close(); 
     } 
} 
} 

Et log chat me donner cette erreur

10-10 21:25:38.115: ERROR/Database(26775): close() was never explicitly called on database '/data/data/com.rbrlnx.lugares/databases/db.db' 
10-10 21:25:38.115: ERROR/Database(26775): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here 

et

10-10 21:35:48.831: ERROR/AndroidRuntime(27458): FATAL EXCEPTION: main 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.rbrlnx.lugares/com.rbrlnx.lugares.listatab}: java.lang.NullPointerException 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1872) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.app.ActivityThread.startActivityNow(ActivityThread.java:1692) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:656) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.widget.TabHost.setCurrentTab(TabHost.java:326) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.widget.TabHost$2.onTabSelectionChanged(TabHost.java:132) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.widget.TabWidget$TabClickListener.onClick(TabWidget.java:458) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.view.View.performClick(View.java:2533) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.view.View$PerformClick.run(View.java:9320) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.os.Handler.handleCallback(Handler.java:587) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.os.Handler.dispatchMessage(Handler.java:92) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.os.Looper.loop(Looper.java:150) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.app.ActivityThread.main(ActivityThread.java:4389) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at java.lang.reflect.Method.invokeNative(Native Method) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at java.lang.reflect.Method.invoke(Method.java:507) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at dalvik.system.NativeStart.main(Native Method) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458): Caused by: java.lang.NullPointerException 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at com.rbrlnx.lugares.listatab.onCreate(listatab.java:21) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836) 
10-10 21:35:48.831: ERROR/AndroidRuntime(27458):  ... 18 more 

Je ne sais pas pourquoi, n'importe qui peut m'aider s'il vous plaît?

Answer 1

Vous n'avez pas créé votre instance DataBaseHelper. Vous avez besoin de:

ayudabbdd = new DataBaseHelper(this); 

avant d'appeler la méthode getNombers().

Answer 2

Vous devez appeler manuellement openDataBase dans onCreate avant d'appeler db.execSQL:

 public void onCreate(SQLiteDatabase db){ 
     try { 
      openDataBase(); 
      db.execSQL(CREATE_TABLE); 
     } catch (Exception e) { 
      // handle exception 
     }    
    } 

De même, votre méthode onUpgrade doit ouvrir la première base de données avant d'appeler db.execSQL sinon vous obtiendrez le même type d'erreur. Et je ne pense pas que vous devriez appeler manuellement onCreate de onUpgrade, trouver une manière différente d'accomplir ce que vous essayez là.

Answer 3

Utilisation Il

DataBaseHelper ayudabbdd=new DataBaseHelper(this); 
    SQLiteDatabase db=ayudabbdd.getReadableDatabase(); 
    Cursor cur=db.<Method Name which you want to use>; 

mais je ne sais pas ce que l'utilisation de

nombresC = ayudabbdd.getNombres(); 

et vous avez beaucoup erreur d'orthographe pendant que vous table que vous créez les supprimer également après vérification,

like nol null in place of not null