Android cache mechanism return multi result

Question

in my cache mechanism after add the request to the RequestQueue and try to fetch data from server, my cache method return multi duplicate result from server return json string

RequestQueue queue = Volley.newRequestQueue(this);
String url = Globals.getHostAddress() + "/get_latest_video";

items.clear();
CacheRequest cacheRequest = new CacheRequest(0, url, new Response.Listener<NetworkResponse>() {
    @Override
    public void onResponse(NetworkResponse response) {
        try {
            final String jsonString = new String(response.data,
                    HttpHeaderParser.parseCharset(response.headers));
            Log.e("allVideos", jsonString);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } 
    }
}, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
    }
});
// Add the request to the RequestQueue.
queue.add(cacheRequest);

server return this result:

{"id":12,"channel_id":7,"category_id":8}

Cache mechanism return :

{"id":12,"channel_id":7,"category_id":8},{"id":12,"channel_id":7,"category_id":8}

whats my code problem to cache data and using that?

CacheRequest class content:

public class CacheRequest extends Request<NetworkResponse> {
    private final Response.Listener<NetworkResponse> mListener;
    private final Response.ErrorListener mErrorListener;

    public CacheRequest(int method, String url, Response.Listener<NetworkResponse> listener, Response.ErrorListener errorListener) {
        super(method, url, errorListener);
        this.mListener = listener;
        this.mErrorListener = errorListener;
    }


    @Override
    protected Response<NetworkResponse> parseNetworkResponse(NetworkResponse response) {
        Cache.Entry cacheEntry = HttpHeaderParser.parseCacheHeaders(response);
        if (cacheEntry == null) {
            cacheEntry = new Cache.Entry();
        }
        final long cacheHitButRefreshed = 3 * 60 * 1000; // in 3 minutes cache will be hit, but also refreshed on background
        final long cacheExpired = 24 * 60 * 60 * 1000; // in 24 hours this cache entry expires completely
        long now = System.currentTimeMillis();
        final long softExpire = now + cacheHitButRefreshed;
        final long ttl = now + cacheExpired;
        cacheEntry.data = response.data;
        cacheEntry.softTtl = softExpire;
        cacheEntry.ttl = ttl;
        String headerValue;
        headerValue = response.headers.get("Date");
        if (headerValue != null) {
            cacheEntry.serverDate = HttpHeaderParser.parseDateAsEpoch(headerValue);
        }
        headerValue = response.headers.get("Last-Modified");
        if (headerValue != null) {
            cacheEntry.lastModified = HttpHeaderParser.parseDateAsEpoch(headerValue);
        }
        cacheEntry.responseHeaders = response.headers;
        return Response.success(response, cacheEntry);
    }

    @Override
    protected void deliverResponse(NetworkResponse response) {
        mListener.onResponse(response);
    }

    @Override
    protected VolleyError parseNetworkError(VolleyError volleyError) {
        return super.parseNetworkError(volleyError);
    }

    @Override
    public void deliverError(VolleyError error) {
        mErrorListener.onErrorResponse(error);
    }
}

UPDATED POST:

public class ActivityBootstrap extends Activity implements AdapterView.OnItemClickListener {

    @InjectView(R.id.drawer_list)
    ListView drawer_list;

    @InjectView(R.id.drawer_layout)
    DrawerLayout drawer_layout;

    @InjectView(R.id.listView)
    AsymmetricGridView listView;

    private List<DrawerItem> drawer_items = new ArrayList<DrawerItem>();
    private List<VideoItems> items = new ArrayList<>();
    private DrawerAdatper drawer_adatper = null;
    private boolean mDrawerState = false;
    private VideoAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.inject(this);

        RequestQueue queue = Volley.newRequestQueue(this);
        String url = Globals.getHostAddress() + "/get_latest_video";

        items.clear();
        CacheRequest cacheRequest = new CacheRequest(0, url, new Response.Listener<NetworkResponse>() {
            @Override
            public void onResponse(NetworkResponse response) {
                try {
                    final String jsonString = new String(response.data,
                            HttpHeaderParser.parseCharset(response.headers));
                    Log.e("allVideos", jsonString);
                    JSONArray jsonArray = new JSONArray(jsonString);
                    for (int i = 0; i < jsonArray.length(); i++) {
                        JSONObject video_single_item = jsonArray.getJSONObject(i);
                        int video_id = video_single_item.getInt("id");
                        String video_thumbnail = video_single_item.getString("thumbnail");
                        int colSpan = Math.random() < 0.2f ? 2 : 1;
                        int rowSpan = colSpan;
                        VideoItems item = new VideoItems(colSpan, rowSpan, video_thumbnail,video_id);
                        items.add(item);
                    }
                    setUpListView(items);
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
            }
        });
        // Add the request to the RequestQueue.
        queue.add(cacheRequest);

    }

    private void setUpListView(List video_array_items) {
        final List<AsymmetricItem> items = new ArrayList<>();

        adapter = new VideoListAdapter(this, video_array_items);
        AsymmetricGridViewAdapter asymmetricAdapter =
                new AsymmetricGridViewAdapter<>(this, listView, adapter);
        listView.setAdapter(asymmetricAdapter);
        listView.setRequestedColumnCount(3);
        listView.setAdapter(getNewAdapter());
        listView.setOnItemClickListener(this);
        listView.setAllowReordering(true);
        listView.isAllowReordering();
    }

    private AsymmetricGridViewAdapter<?> getNewAdapter() {
        return new AsymmetricGridViewAdapter<>(this, listView, adapter);
    }

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
        int video_position = items.get(position).getVideo_id();

        Intent intent = new Intent(ActivityBootstrap.this, ActivitySHowVideoDetaile.class);
        intent.putExtra("video_id", video_position);
        startActivity(intent);
    }
}

UPDATED POST 2)

Result of Log.e("allVideos", jsonString); is :

10-28 09:51:46.016 17872-17872/pishguy.ir.asrebidree E/allVideos: [{"id":12,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"},{"id":10,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"}]
10-28 09:51:47.249 17872-17872/pishguy.ir.asrebidree E/allVideos: [{"id":12,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"},{"id":10,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"}]

Result of server response i'm test it with browser:

[{"id":12,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"},{"id":10,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"}]

UNFORTUNATELY this duplicate result is random(NOT duplicate every time)

UPDATE 3:

10-28 13:14:52.322 16129-16129/pishguy.ir.asrebidree E/Test: onCreate called
10-28 13:14:52.513 16129-16129/pishguy.ir.asrebidree E/allVideos: [{"id":12,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"},{"id":10,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"}]
10-28 13:14:53.206 16129-16129/pishguy.ir.asrebidree E/allVideos: [{"id":12,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"},{"id":10,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"}]

Answer 1

Because I have commented too many lines and I cannot re-produce "duplication behavior" as your current issue, so I post my answer here, hope this helps!

Inside CacheDispatcher class, you will find the following:

                if (!entry.refreshNeeded()) {
                    // Completely unexpired cache hit. Just deliver the response.
                    mDelivery.postResponse(request, response);
                } else {
                    // Soft-expired cache hit. We can deliver the cached response,
                    // but we need to also send the request to the network for
                    // refreshing.
                    request.addMarker("cache-hit-refresh-needed");
                    request.setCacheEntry(entry);

                    // Mark the response as intermediate.
                    response.intermediate = true;

                    // Post the intermediate response back to the user and have
                    // the delivery then forward the request along to the network.
                    mDelivery.postResponse(request, response, new Runnable() {
                        @Override
                        public void run() {
                            try {
                                mNetworkQueue.put(request);
                            } catch (InterruptedException e) {
                                // Not much we can do about this.
                            }
                        }
                    });
                }

IMO, it is possible the softTtl that is causing this duplication behavior.

I suggest that you use the following line to setRetryPolicy for your request:

cacheRequest.setRetryPolicy(new DefaultRetryPolicy(DefaultRetryPolicy.DEFAULT_TIMEOUT_MS * 2, 0, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
// Add the request to the RequestQueue.
queue.add(cacheRequest);