Updating Listview Without Duplication

I am writing a music player application with playlists, and I am trying to display the songs that have been chosen. All of the code for that works fine, but when a song is added, t

Solution 1:

1. Do this in your Activity Class.

   publicclassMyActivityextendsActivity {
   
   privateSongListAdapter _songListAdapter;
      @OverridepublicvoidonCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
         createLeftList();
      }
   
      privatevoidcreateLeftList(){
        DatabaseHandler db = newDatabaseHandler(this);
        ListView leftSongView = (ListView) findViewById(R.id.left_playlistView);
        _songListAdapter = newSongListAdapter(this, db.getAllsongs());
         leftSongView.setAdapter(_songListAdapter);
      }
   
     //TODO use this whenever you wanna update your list.publicvoidupdateSongView(List<String> songsList){
       if(_songListAdapter != null && songsList != null){
           _songListAdapter.updateMusicList(songsList);
       }
     }
   }
   

2. Then create and Adapter class and follow the pattern.

   publicclassSongListAdapterextendsBaseAdapter{
   privateContext _context;
   privateList<String> musicList = newArrayList();
   
   publicSongListAdapter(Context context, List<String> musicList){
       _context = context;
       this.musicList.clear();
       this.musicList.addAll(musicList);
   }
   
   publicvoidupdateMusicList(List<String> musicList){
       this.musicList.clear();
       this.musicList.addAll(musicList);
       notifyDataSetChanged();
   }
   
   @Overridepublic int getCount() {
       return musicList.size();
   }
   
   @OverridepublicObjectgetItem(int position) {
       return musicList.get(position);
   }
   
   @Overridepublic long getItemId(int position) {
       return position;
   }
   
   @OverridepublicViewgetView(int position, View convertView, ViewGroup parent) {
   
       if(convertView == null){
           convertView = LayoutInflater.from(_context).inflate(R.layout.music_view, parent, false);
   
           // TODO folow view holder pattern.
       }
   
       String music = (String) getItem(position);
       if(music != null){
   
           //TODO update your views Here
       }
   
       return convertView;
   }
   
   @OverridepublicvoidnotifyDataSetChanged() {
       super.notifyDataSetChanged();
   
       //TODO peform any custon action when this is called if needed.
   }
   }