How to use MediaStore query to get Artists without duplicates?

问题

I would like to get all the artists names on my phone by using MediaStore ;Already I have the whole list but with duplicates of all entries due to multiple links songs/artists. Is there any way to use the query to get only one of each, without any duplicates?

There is my query :

    String selection = MediaStore.Audio.Media.IS_MUSIC + " != 0";

    String[] projection = {
            MediaStore.Audio.Media.ALBUM,
            MediaStore.Audio.Media.ARTIST,
            MediaStore.Audio.Media.TITLE,
            MediaStore.Audio.Media.DATA,
            MediaStore.Audio.Media.DURATION
    };
    Cursor cursor = context.getContentResolver().query(
            MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
            projection,
            selection,
            null,
            null);

Thanks in advance !

回答1:

Using the keyword DISTINCT in the query returns non duplicate values For example, listing only album names when querying many audio numbers

        new String[] { "DISTINCT " + MediaStore.Audio.Playlists.Members.ALBUM_ID + " as _id"}

but I found you can only return one column

I kept it simple and did the following when looping through the cursor. Pass the value, in your case the artist,

    if (value.length() > 0) {
        // check if value already exists
        if (!listItems.contains(value)) {
            // doesn't exist, add it
            listItems.add(value);
        }

    }

This is a simple method. You can check this out in my app Playlist Manager on Google Play. I use this technique for selecting artists, years, etc.

回答2:

For people who are still looking for an answer to this, I'd suggest doing the following:

String[] mProjection =
         {
                MediaStore.Audio.Artists._ID,
                MediaStore.Audio.Artists.ARTIST,
                MediaStore.Audio.Artists.NUMBER_OF_TRACKS,
                MediaStore.Audio.Artists.NUMBER_OF_ALBUMS
         };

Cursor artistCursor = mContentResolver.query(
                MediaStore.Audio.Artists.EXTERNAL_CONTENT_URI,
                mProjection,
                null,
                null,
                MediaStore.Audio.Artists.ARTIST + " ASC");

Now you can query this cursor to get the name of all artists. There won't be any duplicates.
I understand that this is not the solution to "get unique values from MediaStore" in general. But it would solve this very specific problem.

Explanation:
You just have to query the right table, which in this case was the "Artist" table, while the op was querying the "Media" table.

Hope this helps someone.

回答3:

Well to avoid that problem, I used the keyword "UNIQUE" when I create my tables.

回答4:

public ArrayList getAlbumList() {

            ArrayList<SongBeen> albumList=new ArrayList<SongBeen>();
            ContentResolver musicResolver = activity.getContentResolver();
            Uri musicUri = android.provider.MediaStore.Audio.Artists.EXTERNAL_CONTENT_URI;
            Cursor musicCursor = musicResolver.query(musicUri, null, null, null, null);
            if(musicCursor!=null && musicCursor.moveToFirst()){

                int titleColumn = musicCursor.getColumnIndex
                        (android.provider.MediaStore.Audio.Media.TITLE);
                int idColumn = musicCursor.getColumnIndex
                        (android.provider.MediaStore.Audio.Media._ID);
                int artistColumn = musicCursor.getColumnIndex
                        (android.provider.MediaStore.Audio.Media.ARTIST);
                int albumColumn = musicCursor.getColumnIndex
                        (android.provider.MediaStore.Audio.Media.ALBUM);


                //add songs to list
                do {
                    SongBeen been=new SongBeen();


                    been.setId(musicCursor.getLong(idColumn));
                    been.setAlbum(musicCursor.getString(albumColumn));
                    been.setArtist(musicCursor.getString(artistColumn));


                    albumList.add(been);
            } 
                while (musicCursor.moveToNext());
            }
            return albumList;

        }

来源：https://stackoverflow.com/questions/22190876/how-to-use-mediastore-query-to-get-artists-without-duplicates

标签

android

mediastore