title: Cannot resolve method getWritableDatabase() in Android Studio
body: <p>I'm using SQLite for the first time in Android. I would like to add new crises can be done in the background. But I encounter an error when I call the reference to write to the database.I try to add new crises in my database using an asyncTasck method. The code that isn't working is in the method <strong>void addCrisi(Crisi crisi)</strong>. Here is it:</p>
  
  <pre><code>// 1. get reference to writable DB
  SQLiteDatabase db = this.getWritableDatabase();
  </code></pre>
  
  <p>Full code is:</p>
  
  <pre><code> public class DatabaseHandler extends SQLiteOpenHelper {
  // All Static variables
  // Database Version
  private static final int DATABASE_VERSION = 1;
  
  // Database Name
  private static final String DATABASE_NAME = "crisisManager";
  
  // Crisis table name
  private static final String TABLE_CRISIS = "crisis";
  //Singleton
  private static DatabaseHandler instance;
  public static DatabaseHandler getInstance(Context context) {
      if (instance == null) {
          instance = new DatabaseHandler(context.getApplicationContext());
      }
      return instance;
  }
  
  // Crisis Table Columns names
  private static final String KEY_ID = "id";
  private static final String KEY_START_DATE = "start_date";
  private static final String KEY_END_DATE = "end_date";
  private static final String KEY_LATITUDE = "latitude";
  private static final String KEY_LONGITUDE = "longitude";
  
  public DatabaseHandler(Context context) {
      super(context, DATABASE_NAME, null, DATABASE_VERSION);
  }
  
  // Creating Tables
  public void onCreate(SQLiteDatabase db) {
      String CREATE_CRISIS_TABLE = "CREATE TABLE " + TABLE_CRISIS + "("
              + KEY_ID + " INTEGER PRIMARY KEY,"
              + KEY_START_DATE + " TEXT,"
              + KEY_END_DATE + " TEXT,"
              + KEY_LATITUDE + " DOUBLE,"
              + KEY_LONGITUDE + " DOUBLE" + ")";
      db.execSQL(CREATE_CRISIS_TABLE);
  }
  
  // Upgrading database
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
      // Drop older table if existed
      db.execSQL("DROP TABLE IF EXISTS " + TABLE_CRISIS);
      // Create tables again
      onCreate(db);
  }
  
  /**
   * All CRUD(Create, Read, Update, Delete) Operations
   */
  // Adding new crisi
  void addCrisi(Crisi crisi) {
      Log.d("Add Crisi", crisi.toString());
      //SQLiteDatabase db = this.getWritableDatabase();
  
      ContentValues values = new ContentValues();
      values.put(KEY_START_DATE, crisi.getStartDate()); // Start Date
      values.put(KEY_END_DATE, crisi.getEndDate()); // End Date
      values.put(KEY_LATITUDE, crisi.getLatitude()); // Latitude
      values.put(KEY_LONGITUDE, crisi.getLongitude()); // Longitude
  
      // Inserting Row Async Inserting
      //AsyncTask is anonymous class
      new AsyncTask&lt;ContentValues, Void, Void&gt;() {
          @Override
          protected Void doInBackground(ContentValues... params) {
  
              // 1. get reference to writable DB
              SQLiteDatabase db = this.getWritableDatabase();
  
              // 3. insert
              db.insert(TABLE_CRISIS, null, params[0]);
  
              // 4. close
              db.close();
              return null;
          }
      }.execute(values);
      //db.insert(TABLE_CRISIS, null, values);
      //db.close(); // Closing database connection
  }
  // Getting All Crisis
  public List&lt;Crisi&gt; getAllCrisis() {
      List&lt;Crisi&gt; crisiList = new ArrayList&lt;Crisi&gt;();
      // Select All Query
      String selectQuery = "SELECT  * FROM " + TABLE_CRISIS;
  
      SQLiteDatabase db = this.getWritableDatabase();
      Cursor cursor = db.rawQuery(selectQuery, null);
  
      // looping through all rows and adding to list
      if (cursor.moveToFirst()) {
          do {
              Crisi crisi = new Crisi();
              crisi.setId(Integer.parseInt(cursor.getString(0)));
              //crisi.setName(cursor.getString(1));
              //crisi.setPhoneNumber(cursor.getString(2));
              crisi.setStartDate(cursor.getString(1));
              crisi.setEndDate(cursor.getString(2));
              crisi.setLatitude(Double.parseDouble(cursor.getString(3)));
              crisi.setLongitude(Double.parseDouble(cursor.getString(4)));
              // Adding crisi to list
              crisiList.add(crisi);
          } while (cursor.moveToNext());
      }
  
      // return crisi list
      return crisiList;
  }
  
  // Updating single crisi
  public int updateCrisi(Crisi crisi) {
      SQLiteDatabase db = this.getWritableDatabase();
  
      ContentValues values = new ContentValues();
      values.put(KEY_START_DATE, crisi.getStartDate());
      values.put(KEY_END_DATE, crisi.getEndDate());
      values.put(KEY_LATITUDE, crisi.getLatitude()); // Latitude
      values.put(KEY_LONGITUDE, crisi.getLongitude()); // Longitude
      values.put(KEY_LOCALITY, crisi.getLatitude()); // Locality
      values.put(KEY_COUNTRY, crisi.getLongitude()); // Country
  
      // updating row
      return db.update(TABLE_CRISIS, values, KEY_ID + " = ?",
              new String[] { String.valueOf(crisi.getId()) });
  }
  
  // Deleting single crisi
  public void deleteCrisi(Crisi crisi) {
      SQLiteDatabase db = this.getWritableDatabase();
      db.delete(TABLE_CRISIS, KEY_ID + " = ?",
              new String[] { String.valueOf(crisi.getId()) });
      db.close();
  }
  
  // Getting crisis Count
  public int getCrisisCount() {
      String countQuery = "SELECT  * FROM " + TABLE_CRISIS;
      SQLiteDatabase db = this.getReadableDatabase();
      Cursor cursor = db.rawQuery(countQuery, null);
      cursor.close();
  
      // return count
      return cursor.getCount();
  }
  }
  </code></pre>
  
  <p>Can someone please help? Thanks!
  Ps: I apologize in advance for my bad English.</p>