andorid - showing a different layout if there are no objects in adapter

Question

I'm trying to show all songs that are on the SD card. The code works fine if there is at least one song, but I get a NullPointerException if there are no songs, so I wanted to replace the listview with a new layout in case there are no songs like "sorry, nothing to show here"

I tried several ways but I always get a NullPointerException on the method getCount() of my adapter

So...here is my code:

ListFragment.java

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    mInflater = inflater;
    rootView   =  inflater.inflate(R.layout.fragment_list, container, false);
    mContext = container.getContext();
    mContainer = container;

    mAdapterListFile = new SongsAdapter(mContext, mSongList);
    mListSongs = (ListView) rootView.findViewById(R.id.listView_songs);
    mListSongs.setAdapter(mAdapterListFile);

    mSongList = new ArrayList<Song>();
    mSongList = listAllSongs();  //there will be added all songs found in SD card        
    return rootView;
}
private ArrayList<Song> listAllSongs() {
    Cursor cursor;
    ArrayList<Song> songList = new ArrayList<Song>();

    Uri allSongsUri  = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    String selection = MediaStore.Audio.Media.IS_MUSIC + " != 0";
    String orderBy   = MediaStore.Audio.Media.TITLE + " ASC";
    if (isSdPresent()) {

        cursor = getActivity().getContentResolver().query(allSongsUri, STAR, selection, null, orderBy);

        if (cursor != null) {
            if (cursor.moveToFirst()) {
                do {
                    Song song = new Song();

                    String data = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DISPLAY_NAME));
                    String[] res = data.split("\\.");
                    song.setSongName(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.TITLE)));        //song name                        song.setSongFullPath(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA)));     //directory
                    song.setSongId(cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media._ID)));               //id song                       
song.setSongAlbumName(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM)));   //album 

song.setSongArtistName(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST))); //artist                    song.setAlbumImage(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Albums.ALBUM_ART))); 


                    song.setSongUri(ContentUris.withAppendedId(
                            android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                            cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media._ID))));
                    String duration = getDuration(Integer.parseInt(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DURATION))));  //duration
                    song.setSongDuration(duration);
                    songList.add(song);
                                        } while (cursor.moveToNext());
                return songList;
            }
            cursor.close();
        }
    }        return null;
}
private static boolean isSdPresent() {
    return android.os.Environment.getExternalStorageState()
                            .equals(android.os.Environment.MEDIA_MOUNTED);
}

SongsAdapter.java

public class SongsAdapter extends BaseAdapter {
private Context mContext;
private ArrayList<Song> songList;//Data Source for ListView

public SongsAdapter(Context context, ArrayList<Song> list) {

    this.mContext = context;
    this.songList = list;
}

@Override
public int getCount() {
    return songList.size();
}

@Override
public Song getItem(int position) {
    return songList.get(position);
}

@Override
public long getItemId(int position) {
    return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    if (convertView == null) {
        //Layout inflate for list item
        convertView = LayoutInflater.from(mContext).inflate(R.layout.list_item, null);
    }

    ImageView mImgSong = (ImageView) convertView.findViewById(R.id.copertina_album);
    TextView mTxtSongName = (TextView) convertView.findViewById(R.id.titolo_brano);
    TextView mTxtArtista = (TextView) convertView.findViewById(R.id.artista);
    TextView mTxtSongDuration = (TextView) convertView.findViewById(R.id.durata);

    mImgSong.setImageResource(R.drawable.vector_vinyl);
    mTxtSongName.setText(songList.get(position).getSongName());
    mTxtArtista.setText(songList.get(position).getArtistName());
    mTxtSongDuration.setText(songList.get(position).getSongDuration());


    return convertView;
}

public void setSongsList(ArrayList<Song> list) {
    songList = list;
    this.notifyDataSetChanged();
       }
}

Any suggestions?

Possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — maximede, Apr 04 '16 at 16:23

score 1 · Answer 1 · answered Apr 04 '16 at 16:23

1

The ListView has the setEmptyView method, where you specify the view to appear if the list is empty.

check this here: http://developer.android.com/guide/topics/ui/layout/listview.html

answered Apr 04 '16 at 16:23

Mina Wissa

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score 0 · Answer 2 · answered Sep 21 '17 at 18:20

First in getItemCount() you should do some check like this:

@Override
public int getCount() {
if(songList== null)
        return 0;
    return songList.size();
}

Second in getView()

public View getView(int position, View convertView, ViewGroup parent) {
// check if song list is null and count is null than inlate the view you want to 
// show somethig like this
if(songList== null || songList == 0){
convertView = LayoutInflater.from(mContext).inflate(R.layout.empty_state_view, null);
return convertview;
}
else{
    //your code
}
}

andorid - showing a different layout if there are no objects in adapter

2 Answers2