通过GenericTypeIndicator从Firebase检索数据

Question

我正在尝试从Firebase数据库中检索某个级别的数据，但是我收到了警告

  

类java.util.ArrayList具有泛型类型参数，请改用GenericTypeIndicator

首先，我的数据结构如下：

我试图直接在“游戏”（即Method和Oxley）下检索字段并将其显示在列表视图中，而不是检索游戏的玩家。

这是我的代码

private ListView lv;
List<Game> games = new ArrayList<Game>();
List<String> gameNames = new ArrayList<String>();

final FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("Games");

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sessions);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    lv = (ListView) findViewById(R.id.games);
    final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(
            this,
            android.R.layout.simple_list_item_1,
            gameNames);

    lv.setAdapter(arrayAdapter);

    ref.addChildEventListener(new ChildEventListener(){
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot,String prevChildKey){
            Game newGame = dataSnapshot.getValue(Game.class);
            gameNames.add(newGame.toString());
            arrayAdapter.notifyDataSetChanged();
        }
        @Override
        public void onChildChanged(DataSnapshot dataSnapshot, String prevChildKey) {}

        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {}

        @Override
        public void onChildMoved(DataSnapshot dataSnapshot, String prevChildKey) {}

        @Override
        public void onCancelled(DatabaseError databaseError) {}
    });

}

如果它有助于将游戏放入数据库的代码，我认为它可能与“地图”类型有关，因为我的列表视图在此之前工作正常。

public void beginGame(View view) {
        final FirebaseDatabase database = FirebaseDatabase.getInstance();
        DatabaseReference ref = database.getReference();

        EditText gameNameField = (EditText) findViewById(R.id.gameName);
        String gameName = gameNameField.getText().toString().trim();
        Collections.shuffle(players);
        if (gameName.isEmpty()) {
            int duration = Toast.LENGTH_LONG;

            Toast toast = Toast.makeText(getApplicationContext(),
                    R.string.toast_no_game_name, duration);
            toast.show();

        } else if (playerNames.size() < 2) {
            int duration = Toast.LENGTH_LONG;

            Toast toast = Toast.makeText(getApplicationContext(),
                    R.string.toast_not_enough_players, duration);
            toast.show();

        } else {
            for (int i = 0; i < players.size(); i++) {
                if (i != (players.size() - 1)) {
                    players.get(i).target = players.get(i + 1);
                } else {
                    players.get(i).target = players.get(0);
                }
            }
            Game game = new Game(gameName, players);
            DatabaseReference gamesRef = ref.child("Games").child(gameName).child("players");
            Map<String, Player> gamePlayers = new HashMap<>();
            for(int i = 0; i < players.size(); i++){
                Player currentPlayer = players.get(i);
                gamesRef.child(currentPlayer.getName()).setValue(currentPlayer);

            }