Java Arraylist 已满但不更新？

Question

我正在尝试制作一个可以获取实时游戏得分的应用程序，但在使用 recycleviewer 和 arraylist 时遇到了问题。

RecycleView 工作正常，但当我制作数组列表来填充 RecycleView 时，我遇到了麻烦。这里我只是用 100 个游戏对象填充数组，这样就可以了。我让屏幕充满 100 个随机游戏。

private void updateUI() {

    ArrayList<Games> games = new ArrayList<>();

    for (int i = 0; i < 100; i++) {
        Games g = new Games("t1",110);
        g.setTeam2("T2");
        g.setTeam2_score(120);
        games.add(g);
    }
    mAdapter = new GameAdapter(games);
    mGameRecycleViewer.setAdapter(mAdapter);
}

我不想要任何随机的 100 个对象，我想要获取一天发生的游戏并用它们填充数组。因此，我使用 JSON 来获取游戏，并且由于我输入的这条日志消息，我知道数组中充满了游戏: Log.d("AAAAAHHHHHHH",Integer.toString(games.size()));这告诉我得到这个输出的数组的大小:

D/AAAAAHHHHHHH: 1
D/AAAAAHHHHHHH: 2
D/AAAAAHHHHHHH: 2
 D/AAAAAHHHHHHH: 3
D/AAAAAHHHHHHH: 3
D/AAAAAHHHHHHH: 4
 D/AAAAAHHHHHHH: 4
 D/AAAAAHHHHHHH: 5
D/AAAAAHHHHHHH: 5
D/AAAAAHHHHHHH: 6
D/AAAAAHHHHHHH: 6
D/AAAAAHHHHHHH: 7
D/AAAAAHHHHHHH: 7
D/AAAAAHHHHHHH: 8
D/AAAAAHHHHHHH: 8
D/AAAAAHHHHHHH: 9
D/AAAAAHHHHHHH: 9
D/AAAAAHHHHHHH: 10
D/AAAAAHHHHHHH: 10
D/AAAAAHHHHHHH: 11
 D/AAAAAHHHHHHH: 11

此外，我在不使用回收查看器的情况下尝试了 JSON，并将所有内容输出到屏幕上，这样也能正常工作。问题是，由于某种原因，游戏数组中没有任何内容保留，即使上面显示它在那里。它不会显示在屏幕上。

我还在执行后添加了另一个 logd，它说大小为 0: Log.d("OOOHHHHHHH",Integer.toString(games.size()));

由于某种原因，数组在运行类之外不会被填充。 有人有任何建议，或者知道如何解决它吗？

这是使用 JSON 的 updateUI:

ArrayList<Games> games = new ArrayList<>();

private void updateUI() {
    class run extends AsyncTask<Void,Void,Void> {
        String line = "";
        String data = "";
        @Override
        protected Void doInBackground(Void... voids) {

            try {

                URL url = new URL("https://stats.nba.com/stats/scoreboard/?GameDate=02/13/2019&LeagueID=00&DayOffset=0");

                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                InputStream is = conn.getInputStream();
                BufferedReader bf = new BufferedReader(new InputStreamReader(is));

                while(line!=null){
                    line = bf.readLine();
                    data += line;
                }
                JSONObject jo = new JSONObject(data);

                JSONArray ja = (JSONArray) jo.get("resultSets");
                JSONObject jo2 = (JSONObject) ja.get(1);//Linescores
                JSONArray ja3 = (JSONArray) jo2.get("rowSet");
                JSONArray ja4;

                int count = 0;
                for(int i = 0;i<ja3.length();i++){
                    ja4 = new JSONArray(ja3.get(i).toString());
                    //teams+=ja4.get(4)+": score =  "+ja4.get(21).toString()+"\n";
                    if(count == 1) {
                        games.get(games.size() - 1).setTeam2(ja4.get(4).toString());
                        games.get(games.size() - 1).setTeam2_score(Integer.parseInt(ja4.get(21).toString()));
                        count = 0;
                    }else{
                        games.add(new Games(ja4.get(4).toString(), Integer.parseInt(ja4.get(21).toString())));
                        count = 1;
                    }
                    Log.d("AAAAAHHHHHHH",Integer.toString(games.size()));
                }




            }catch (Exception e){
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            //main.setText(teams);

        }
    }
    run r = new run();

    r.execute();
    mAdapter = new GameAdapter(games);
    mGameRecycleViewer.setAdapter(mAdapter);
}

这是完整的 RecycleViewer:

public class GameListFragment extends Fragment {

private RecyclerView mGameRecycleViewer;
private GameAdapter mAdapter;


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_game_list, container, false);
    mGameRecycleViewer = (RecyclerView) view
            .findViewById(R.id.game_recycler_view);
    mGameRecycleViewer.setLayoutManager(new LinearLayoutManager(getActivity()));

    updateUI();

    return view;
}

private class GameHolder extends RecyclerView.ViewHolder {
    public GameHolder(LayoutInflater inflater, ViewGroup parent) {
        super(inflater.inflate(R.layout.list_game_item, parent, false));
    }

}
private class GameAdapter extends RecyclerView.Adapter<GameHolder> {
    private List<Games> mGames;
    public GameAdapter(List<Games> crimes) {
        mGames = crimes;
    }
    @Override
    public GameHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater = LayoutInflater.from(getActivity());
        return new GameHolder(layoutInflater, parent);
    }
    @Override
    public void onBindViewHolder(GameHolder holder, int position) {
    }
    @Override
    public int getItemCount() {
        return mGames.size();
    }

}
ArrayList<Games> games = new ArrayList<>();

private void updateUI() {
    //GameLab gamelab = GameLab.get(getActivity());
    //ArrayList<Games> crimes = gamelab.getGames();
    //for (int i = 0; i < 100; i++) {
        //Games g = new Games("t1",110);
        //g.setTeam2("T2");
        //g.setTeam2_score(120);
        //games.add(g);
    //}
    class run extends AsyncTask<Void,Void,Void> {
        String line = "";
        String data = "";
        @Override
        protected Void doInBackground(Void... voids) {

            try {

                URL url = new URL("https://stats.nba.com/stats/scoreboard/?GameDate=02/13/2019&LeagueID=00&DayOffset=0");

                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                InputStream is = conn.getInputStream();
                BufferedReader bf = new BufferedReader(new InputStreamReader(is));

                while(line!=null){
                    line = bf.readLine();
                    data += line;
                }
                JSONObject jo = new JSONObject(data);

                JSONArray ja = (JSONArray) jo.get("resultSets");
                JSONObject jo2 = (JSONObject) ja.get(1);//Linescores
                JSONArray ja3 = (JSONArray) jo2.get("rowSet");
                JSONArray ja4;

                int count = 0;
                for(int i = 0;i<ja3.length();i++){
                    ja4 = new JSONArray(ja3.get(i).toString());
                    //teams+=ja4.get(4)+": score =  "+ja4.get(21).toString()+"\n";
                    if(count == 1) {
                        games.get(games.size() - 1).setTeam2(ja4.get(4).toString());
                        games.get(games.size() - 1).setTeam2_score(Integer.parseInt(ja4.get(21).toString()));
                        count = 0;
                    }else{
                        games.add(new Games(ja4.get(4).toString(), Integer.parseInt(ja4.get(21).toString())));
                        count = 1;
                    }
                    Log.d("AAAAAHHHHHHH",Integer.toString(games.size()));
                }




            }catch (Exception e){
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            //main.setText(teams);

        }
    }
    run r = new run();

    r.execute();
    mAdapter = new GameAdapter(games);
    mGameRecycleViewer.setAdapter(mAdapter);
}

}

Answer 1

在获取 json 数据之前已经设置了适配器，因此可能会发送一个空列表。您应该在列表完全填充数据后在 onPostExecute 中设置适配器:

 @Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);
        //main.setText(teams);
        mAdapter = new GameAdapter(games);
        mGameRecycleViewer.setAdapter(mAdapter);

    }