Question

在更新我的RecyclerView适配器之前，我无法等待Volley的响应。我知道请求有OnResponse方法，但是，我无法将适配器作为参数传递给它。有没有一种简单的方法可以通知我的适配器Volley提供了答案？

private static JsonObjectRequest jsonReq = new JsonObjectRequest
            (Request.Method.GET, espUrl, null, new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try {
                        if (espVideos != null) {
                            espVideos.clear();
                        }
                        JSONArray jsonArray = response.getJSONArray("items");
                        for (int i = 0; i < jsonArray.length(); i++) {
                            String id = jsonArray.getJSONObject(i).getJSONObject("contentDetails").getString("videoId");
                            String title = jsonArray.getJSONObject(i).getJSONObject("snippet").getString("title");
                            espVideo = new YTVideo(id, title);
                            espVideos.add(espVideo);
                        }
                        SaveObject.saveYTVArray("espVideos", espVideos);
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                }
});

public static void requestEspeciales(Activity act, ImageAdapterEspeciales adapter) {
    Volley.newRequestQueue(act).add(jsonReq);
    // I WANT TO CALL adapter.notifyDataSetChanged(); AFTER RESPONSE
}

编辑：

我尝试了同步调用，但页面只是冻结了onCreate

synchronized (jsonReq) {
    try {
        jsonReq.wait();
    } catch (InterruptedException e) {
        Log.e("Error", e.toString());
    }
    Log.d("Notifying", espVideo.toString());
    adapter.notifyDataSetChanged();
}

@Override
public void onResponse(JSONObject response) {
    synchronized (jsonReq) {
        try {
            if (espVideos != null) {
                espVideos.clear();
            }
            JSONArray jsonArray = response.getJSONArray("items");
            for (int i = 0; i < jsonArray.length(); i++) {
                String id = jsonArray.getJSONObject(i).getJSONObject("contentDetails").getString("videoId");
                String title = jsonArray.getJSONObject(i).getJSONObject("snippet").getString("title");
                String description = jsonArray.getJSONObject(i).getJSONObject("snippet").getString("description");
                String thumbnailPath = jsonArray.getJSONObject(i).getJSONObject("snippet").getJSONObject("thumbnails").getJSONObject("high").getString("url");
                String correspondingPlaylist = jsonArray.getJSONObject(i).getJSONObject("snippet").getString("playlistId");

                espVideo = new YTVideo(id, title, description, thumbnailPath, correspondingPlaylist);
                espVideos.add(espVideo);
            }
            SaveAndRetrieve.saveYTVArray("espVideos", espVideos);
            Log.d("Retrieving", ((YTVideo) SaveAndRetrieve.getYTVArray("espVideos").get(0)).title);
            notify();
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

Answer 1

只需在您的volleyresponse

中设置您的回收器适配器

@Override
public void onResponse(JSONObject response) {
    synchronized (jsonReq) {
        try {
            if (espVideos != null) {
                espVideos.clear();
            }
            JSONArray jsonArray = response.getJSONArray("items");
            for (int i = 0; i < jsonArray.length(); i++) {
                String id = jsonArray.getJSONObject(i).getJSONObject("contentDetails").getString("videoId");
                String title = jsonArray.getJSONObject(i).getJSONObject("snippet").getString("title");
                String description = jsonArray.getJSONObject(i).getJSONObject("snippet").getString("description");
                String thumbnailPath = jsonArray.getJSONObject(i).getJSONObject("snippet").getJSONObject("thumbnails").getJSONObject("high").getString("url");
                String correspondingPlaylist = jsonArray.getJSONObject(i).getJSONObject("snippet").getString("playlistId");      

                espVideo = new YTVideo(id, title, description, thumbnailPath, correspondingPlaylist);
                espVideos.add(espVideo);
            }
            SaveAndRetrieve.saveYTVArray("espVideos", espVideos);
            Log.d("Retrieving", ((YTVideo) SaveAndRetrieve.getYTVArray("espVideos").get(0)).title);

            **YourAdapaterClass mAdapter = new YourAdapaterClass(youradapterdata);
            recyclerview.setAdapter(mAdapter);**             
            notify();
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

Answer 2

我无法将适配器作为参数传递给它。

你实际上有两种方式。

使适配器成为围绕Volley请求的方法的final参数。换句话说，将请求从静态字段移动到方法中。
更优选的是，使适配器成为类

两种方式都允许您从onResponse方法

等待Volley返回更新适配器的答案

2 个答案: