public boolean ComprobarCodiArticulo(long id){
    boolean Existe = true;

    Cursor resultadoSelect = dbRead.rawQuery("SELECT " + ARTICLES_codiArticulo + " FROM " + table_ARTICLES + " WHERE " + ARTICLES_codiArticulo + "=" + LLAMAR A TEXTVIEW, null);

    if(resultadoSelect.getCount()<=0){
        Existe =false;
    }
    else{
        Existe =true;
    }
    return Existe ;
}

if(bd.ComprobarCodiArticulo(idTask) == true){
                Toast.makeText(this, "Este codigo ya existe", Toast.LENGTH_SHORT).show();
            }