title: Delete all rows from a table, throws nullpointer
body: <p>I'm trying to write a function that will delete every row in a given table but I'm getting a null pointer exception. Could somebody point me in the right direction? Here is the code...</p>
  
  <pre><code>   public void deleteall(){
      SQLiteDatabase db = tweets.getWritableDatabase();
      String delete = "TRUNCATE FROM tweets";
      db.rawQuery(delete, null);
  
        }
  </code></pre>