這篇介紹如何實作DatabaseContract，主要用於對接view與presenter

DatabaseContract

public interface DatabaseContract {
    interface view{
        void addSuccess();
        void addError();
        void getSuccess(String getId,
                        String getRoomNumber,
                        Boolean getPlayer1OnlineState,
                        Boolean getPlayer2OnlineState,
                        String getMoveState,
                        HashMap<String,Object> getChessboardData,
                        HashMap<String,Object> getChessmanMoveData,
                        String getTurn,
                        HashMap<String,Object> getPawnMove1,
                        HashMap<String,Object> getPawnMove2,
                        HashMap<String,Object> getCastlingMove1,
                        HashMap<String,Object> getCastlingMove2,
                        String getDate,
                        String getPlayer1message,
                        String getPlayer2message,
                        String getWinPlayer);
        void getError();
        void uploadSuccess();
        void uploadError();
        void deleteSuccess();
        void deleteError();
    }
    interface presenter{
        void addData(String roomNumber,
                     Boolean player1OnlineState,
                     Boolean player2OnlineState,
                     String moveState,
                     HashMap<String,Object> chessboardData,
                     HashMap<String,Object> chessmanMoveData,
                     String turn,
                     HashMap<String,Object> pawnMove1,
                     HashMap<String,Object> pawnMove2,
                     HashMap<String,Object> castlingMove1,
                     HashMap<String,Object> castlingMove2,
                     String date,
                     String player1message,
                     String player2message,
                     String winPlayer);
        void getData(String roomNumber);
        void uploadData(String id,
                        String key,
                        Object newValue);
        void deleteData(String id);
    }
}

這樣我們就能成功在各個activity中回調firebase的方法了