Parcel List of List of Parcelable object

Question

So I've parceled lists before, however I'm trying to parcel my GameBoard object, which actually has a List<List<Tile>>. Tile implements parcelable, but I'm not sure exactly how to parcel the List<List>. Here's what I've tried:

public class GameBoard implements Parcelable {
    private String _id;
    public String getId() { return _id; }
    public void setId(String id) { _id = id; }

    private List<List<Tile>> _tiles;
    public List<List<Tile>> getTiles() { return _tiles; }
    public void setTiles(List<List<Tile>> tiles) { _tiles = tiles; }

    public GameBoard(Parcel in) {
        _id = in.readString();
        in.readList(_tiles, ArrayList.class.getClassLoader());
    }

    public GameBoard() {

    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeString(_id);
        parcel.writeList(_tiles);
    }

    public static final Parcelable.Creator<GameBoard> CREATOR = new Parcelable.Creator<GameBoard>() {
        public GameBoard createFromParcel(Parcel in) {
            return new GameBoard(in);
        }

        public GameBoard[] newArray(int size) {
            return new GameBoard[size];
        }
    };

The tile class correctly implements parcelable, I'm just not exactly sure how to read / write the List<List>> when parceling this class. Any ideas?

Here's one idea from previous questions ; http://stackoverflow.com/a/16529389/680519 . — harism, May 31 '15 at 21:12
@harism Thanks for the link, managed to get a working solution. — Kevin DiTraglia, May 31 '15 at 21:29

score 1 · Accepted Answer · answered May 31 '15 at 21:27

Based on comments, I extended the ArrayList class with my custom class and implemented parcelable:

public class TileList extends ArrayList<Tile> implements Parcelable {

    public TileList(){
        super();
    }

    protected TileList(Parcel in) {
        in.readTypedList(this, Tile.CREATOR);
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeTypedList(this);
    }

    public static final Parcelable.Creator<TileList> CREATOR = new Parcelable.Creator<TileList>() {
        public TileList createFromParcel(Parcel in) {
            return new TileList(in);
        }

        public TileList[] newArray(int size) {
            return new TileList[size];
        }
    };
}

and slight changes to my other class:

public class GameBoard implements Parcelable {
    private String _id;
    public String getId() { return _id; }
    public void setId(String id) { _id = id; }

    private List<TileList> _tiles;
    public List<TileList> getTiles() { return _tiles; }
    public void setTiles(List<TileList> tiles) { _tiles = tiles; }

    public GameBoard(Parcel in) {
        _id = in.readString();
        _tiles = new ArrayList<>();
        in.readTypedList(_tiles, TileList.CREATOR);
    }

    public GameBoard() {

    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeString(_id);
        parcel.writeTypedList(_tiles);
    }

    public static final Parcelable.Creator<GameBoard> CREATOR = new Parcelable.Creator<GameBoard>() {
        public GameBoard createFromParcel(Parcel in) {
            return new GameBoard(in);
        }

        public GameBoard[] newArray(int size) {
            return new GameBoard[size];
        }
    };
}

Could you help me with this? https://stackoverflow.com/questions/69976135/how-to-read-listlistlistdouble-using-parcelable-in-android — Roon13, Nov 15 '21 at 18:53

Parcel List of List of Parcelable object

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