public void addItemUnique(Artist a){
synchronized (mArtists) {
    if (!mArtists.contains(a)) {
      mArtists.add(a);
      sortList();
    }
  }
}

public void addItemUnique ( Artist a ) { synchronized ( mArtists ) { if ( ! mArtists . contains ( a ) ) { mArtists . add ( a ) ; sortList ( ) ; } } }
adds an item to the adapter if it ' s not already there
