Java 代码“；跳绳；JSON对象请求中的响应侦听器（截取）

我目前正在开发一个应用程序，我想阅读Spotify播放列表中给定ID的所有歌曲。我使用的是Volley、Gson和Spotify android认证。我已经成功地从Web API获得了所有用户播放列表的列表，但是在添加了歌曲阅读类之后，当我运行应用程序时，返回的歌曲数组是空的，并且在调试面板中，程序似乎跳过了responseListener（我还添加了多个未打印的日志语句以确保）. 这是我的第一个android应用程序，我是Volley的新手，所以我感谢任何帮助

以下是歌曲阅读器代码：

public class SongReaderSpotify {
    private static final String ENDPOINT = "https://api.spotify.com/v1/playlists";
    private SharedPreferences msharedPreferences;
    private RequestQueue mqueue;
    private ArrayList<Song> slist = new ArrayList<Song>();
    private String playlistid;
    private String templink;
    public SongReaderSpotify(RequestQueue queue, SharedPreferences sharedPreferences, String id) {
        mqueue = queue;
        msharedPreferences = sharedPreferences;
        playlistid = id;
         templink = ENDPOINT +"/" +playlistid +"/tracks";
    }

    public ArrayList<Song> getSongs() {
        return slist;
    }

    public ArrayList<Song> get(final VolleyCallBack callBack) {
        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest
                (Request.Method.GET, templink, null, response -> {
                    Gson gson = new Gson();
                    Log.d("RESPONSE",response.toString());
                    JSONArray jsonArray = response.optJSONArray("items");
                    Log.d("RESPONSE",response.toString());
                    for (int n = 0; n < jsonArray.length(); n++) {
                        try {
                            JSONObject object = jsonArray.getJSONObject(n);
                            Log.d("RESPONSE OBJECT",object.toString());
                            JSONArray artistarr = object.optJSONArray("artists");
                            object = object.optJSONObject("track");
                            Song s = gson.fromJson(object.toString(), Song.class);
                            Log.d("SONG FIELDS",s.toString());
                            List<Artist> temp = new ArrayList<Artist>();
                            for(int i =0;i<artistarr.length();i++)
                            {
                                //GETTING Artists
                                try{
                                    JSONObject o = artistarr.getJSONObject(i);
                                    Artist a = gson.fromJson(o.toString(),Artist.class);
                                    Log.d("ARTISTNAME",a.getName());
                                    temp.add(a);
                                }
                                catch (JSONException e)
                                {
                                    e.printStackTrace();
                                }
                            }
                            s.setsArtists(temp);
                            slist.add(s);
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                    callBack.onSuccess();
                }, error -> {
                    // TODO: Handle error

                }) {
            @Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                Map<String, String> headers = new HashMap<>();
                String token = msharedPreferences.getString("token", "");
                String auth = "Bearer " + token;
                headers.put("Authorization", auth);
                return headers;
            }
        };
        mqueue.add(jsonObjectRequest);
        Log.d("SONGLIST", slist.toString());
        return slist;
    }

}

以下是检索用户播放列表的脚本供参考：

public class UserPlaylistsSpotify {
    private static final String ENDPOINT = "https://api.spotify.com/v1/me/playlists";
    private SharedPreferences msharedPreferences;
    private RequestQueue mqueue;
    private ArrayList<Playlist> plist = new ArrayList<Playlist>();

    public UserPlaylistsSpotify(RequestQueue queue, SharedPreferences sharedPreferences) {
        mqueue = queue;
        msharedPreferences = sharedPreferences;
    }

    public ArrayList<Playlist> getPlaylists() {
        return plist;
    }

    public ArrayList<Playlist> get(final VolleyCallBack callBack) {
        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest
                (Request.Method.GET, ENDPOINT, null, response -> {
                    Gson gson = new Gson();
                    JSONArray jsonArray = response.optJSONArray("items");

                    for (int n = 0; n < jsonArray.length(); n++) {
                        try {
                            JSONObject imgobject = jsonArray.getJSONObject(n);

                            JSONObject plobject = jsonArray.getJSONObject(n);
                            Playlist p = gson.fromJson(plobject.toString(),Playlist.class);
                            JSONArray loopar = imgobject.optJSONArray("images");
                            List<Image> temp = new ArrayList<Image>();
                            for(int j = 0; j < loopar.length();j++)
                            {
                                //GETTING IMAGES
                                try{
                                    JSONObject o = loopar.getJSONObject(j);
                                    Image i = gson.fromJson(o.toString(),Image.class);
                                    temp.add(i);
                                }
                                catch (JSONException e)

                             {
                                    e.printStackTrace();
                                }
                            }
                            p.addToImages(temp);
                            plist.add(p);
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                    callBack.onSuccess();
                }, error -> {
                    // TODO: Handle error

                }) {
            @Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                Map<String, String> headers = new HashMap<>();
                String token = msharedPreferences.getString("token", "");
                String auth = "Bearer " + token;
                headers.put("Authorization", auth);
                return headers;
            }
        };
        mqueue.add(jsonObjectRequest);
        return plist;
    }


}

我也是一个新的共享偏好，但经过一些调试后，似乎歌曲阅读器得到了播放列表阅读器相同的令牌

我一直在这个问题上有一段时间了，所以任何帮助都是非常感谢的！提前感谢：）

public class UserPlaylistsSpotify {
    private static final String ENDPOINT = "https://api.spotify.com/v1/me/playlists";
    private SharedPreferences msharedPreferences;
    private RequestQueue mqueue;
    private ArrayList<Playlist> plist = new ArrayList<Playlist>();

    public UserPlaylistsSpotify(RequestQueue queue, SharedPreferences sharedPreferences) {
        mqueue = queue;
        msharedPreferences = sharedPreferences;
    }

    public ArrayList<Playlist> getPlaylists() {
        return plist;
    }

    public ArrayList<Playlist> get(final VolleyCallBack callBack) {
        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest
                (Request.Method.GET, ENDPOINT, null, response -> {
                    Gson gson = new Gson();
                    JSONArray jsonArray = response.optJSONArray("items");

                    for (int n = 0; n < jsonArray.length(); n++) {
                        try {
                            JSONObject imgobject = jsonArray.getJSONObject(n);

                            JSONObject plobject = jsonArray.getJSONObject(n);
                            Playlist p = gson.fromJson(plobject.toString(),Playlist.class);
                            JSONArray loopar = imgobject.optJSONArray("images");
                            List<Image> temp = new ArrayList<Image>();
                            for(int j = 0; j < loopar.length();j++)
                            {
                                //GETTING IMAGES
                                try{
                                    JSONObject o = loopar.getJSONObject(j);
                                    Image i = gson.fromJson(o.toString(),Image.class);
                                    temp.add(i);
                                }
                                catch (JSONException e)

                             {
                                    e.printStackTrace();
                                }
                            }
                            p.addToImages(temp);
                            plist.add(p);
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                    callBack.onSuccess();
                }, error -> {
                    // TODO: Handle error

                }) {
            @Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                Map<String, String> headers = new HashMap<>();
                String token = msharedPreferences.getString("token", "");
                String auth = "Bearer " + token;
                headers.put("Authorization", auth);
                return headers;
            }
        };
        mqueue.add(jsonObjectRequest);
        return plist;
    }


}

2020-01-24 14:57:03.717 17922-17922/com.example.switcheroo D/STARTING: GOT AUTH TOKEN
2020-01-24 14:57:03.742 17922-17955/com.example.switcheroo D/EGL_emulation: eglMakeCurrent: 0xe7c85540: ver 2 0 (tinfo 0xe7c836f0)
2020-01-24 14:57:03.742 17922-18007/com.example.switcheroo W/cr_CrashFileManager: /data/user/0/com.example.switcheroo/cache/WebView/Crash Reports does not exist or is not a directory
2020-01-24 14:57:04.293 17922-17922/com.example.switcheroo W/mple.switchero: Accessing hidden field Lsun/misc/Unsafe;->theUnsafe:Lsun/misc/Unsafe; (light greylist, reflection)
2020-01-24 14:57:04.340 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/5tSCpEXtiHvlhSQneDTgXL/tracks
2020-01-24 14:57:04.341 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.341 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/3RKyX5h0a24jHAK3PSMRcG/tracks
2020-01-24 14:57:04.342 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.342 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/78awFOWllGbEH0Nskl7Rnh/tracks
2020-01-24 14:57:04.342 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.342 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/37i9dQZF1DX6I0cdp2bBlZ/tracks
2020-01-24 14:57:04.342 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.342 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/37i9dQZF1DX186v583rmzp/tracks
2020-01-24 14:57:04.343 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.343 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/5AQkVd2L8aRfGheTDKYpLi/tracks
2020-01-24 14:57:04.343 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.343 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/3Zu0udhojTUyjnFfnfYrMP/tracks
2020-01-24 14:57:04.343 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.343 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/3NSc2VAy6kGPcaPzmONQlx/tracks
2020-01-24 14:57:04.344 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.344 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/0Z89HetVHGGCYLCKx1EG7i/tracks
2020-01-24 14:57:04.344 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.344 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/3ZkFvyGwLLSBHZc3aamjEl/tracks
2020-01-24 14:57:04.344 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.344 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/37i9dQZF1DZ06evO2QRN3G/tracks
2020-01-24 14:57:04.345 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.345 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/37i9dQZF1DZ06evO30Opqw/tracks
2020-01-24 14:57:04.345 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.345 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/37i9dQZF1DZ06evO1BFaJa/tracks
2020-01-24 14:57:04.345 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.345 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/37i9dQZF1DZ06evO1CSf4Y/tracks
2020-01-24 14:57:04.346 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.348 17922-17922/com.example.switcheroo D/ENDPOINT: https://api.spotify.com/v1/playlists/3EMdqZxxfOIrlhQyiHaNfk/tracks
2020-01-24 14:57:04.348 17922-17922/com.example.switcheroo D/SONGLIST: []
2020-01-24 14:57:04.376 17922-17922/com.example.switcheroo W/ActivityThread: handleWindowVisibility: no activity for token android.os.BinderProxy@7956216
2020-01-24 14:57:04.600 17922-17922/com.example.switcheroo D/AndroidRuntime: Shutting down VM
2020-01-24 14:57:04.602 17922-17922/com.example.switcheroo E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.switcheroo, PID: 17922