Android的缓存机制返回多结果 [英] Android cache mechanism return multi result
本文介绍了Android的缓存机制返回多结果的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
在我的缓存机制的请求后添加到请求队列，并尝试从服务器获取数据，我缓存的方法从服务器返回JSON字符串返回多重复的结果。
请求队列排队= Volley.newRequestQueue（本）;
字符串URL = Globals.getHostAddress（）+/ get_latest_video;
items.clear（）;
CacheRequest cacheRequest =新CacheRequest（0，网址，新Response.Listener＆LT; NetworkResponse＆GT;（）{
@覆盖
公共无效onResponse（NetworkResponse响应）{
尝试 {
最后弦乐jsonString =新的String（response.data，
HttpHeaderParser.parseCharset（response.headers））;
Log.e（allVideos，jsonString）;
}赶上（UnsupportedEncodingException E）{
e.printStackTrace（）;
}
}
}，新Response.ErrorListener（）{
@覆盖
公共无效onErrorResponse（VolleyError错误）{
}
}）;
//增加请求到请求队列。
queue.add（cacheRequest）;
服务器返回结果如下：
{ID：12，CHANNEL_ID：7，CATEGORY_ID：8}
缓存机制的回报：
{ID：12，CHANNEL_ID：7，CATEGORY_ID：8}，{ID：12，CHANNEL_ID：7，CATEGORY_ID：8 }
什么我的code问题来缓存数据和使用？
CacheRequest 类的内容：
公共类CacheRequest扩展请求＆LT; NetworkResponse＆GT; {
私人最终Response.Listener＆LT; NetworkResponse＆GT; mListener;
私人最终Response.ErrorListener mErrorListener;
公共CacheRequest（INT方法，字符串URL，Response.Listener＆LT; NetworkResponse＆GT;听者，Response.ErrorListener errorListener）{
超（方法，URL，errorListener）;
this.mListener =侦听器;
this.mErrorListener = errorListener;
}
@覆盖
受保护的响应和LT; NetworkResponse＆GT; parseNetworkResponse（NetworkResponse响应）{
Cache.Entry cacheEntry = HttpHeaderParser.parseCacheHeaders（响应）;
如果（cacheEntry == NULL）{
cacheEntry =新Cache.Entry（）;
}
最终长cacheHitButRefreshed = 3 * 60 * 1000; //在3分钟内缓存将受到较大冲击，同时也刷新的背景
最终长cacheExpired = 24 * 60 * 60 * 1000; //在24小时内这个缓存条目完全失效
长今= System.currentTimeMillis的（）;
最终长softExpire =现在+ cacheHitButRefreshed;
最终长TTL =现在+ cacheExpired;
cacheEntry.data = response.data;
cacheEntry.softTtl = softExpire;
cacheEntry.ttl = TTL;
字符串headerValue;
headerValue = response.headers.get（日期）;
如果（headerValue！= NULL）{
cacheEntry.serverDate = HttpHeaderParser.parseDateAsEpoch（headerValue）;
}
headerValue = response.headers.get（上次修改）;
如果（headerValue！= NULL）{
cacheEntry.lastModified = HttpHeaderParser.parseDateAsEpoch（headerValue）;
}
cacheEntry.responseHeaders = response.headers;
返回Response.success（响应，cacheEntry）;
}
@覆盖
保护无效deliverResponse（NetworkResponse响应）{
mListener.onResponse（响应）;
}
@覆盖
保护VolleyError parseNetworkError（VolleyError volleyError）{
返回super.parseNetworkError（volleyError）;
}
@覆盖
公共无效deliverError（VolleyError错误）{
mErrorListener.onErrorResponse（错误）;
}
}
修订POST：
公共类ActivityBootstrap扩展活动实现AdapterView.OnItemClickListener {
@InjectView（R.id.drawer_list）
ListView控件drawer_list;
@InjectView（R.id.drawer_layout）
DrawerLayout drawer_layout;
@InjectView（R.id.listView）
AsymmetricGridView的ListView;
私人列表＆LT; DrawerItem＆GT; drawer_items =新的ArrayList＆LT; DrawerItem＆GT;（）;
私人列表＆LT; VideoItems＆GT;项目=新的ArrayList＆LT;＆GT;（）;
私人DrawerAdatper drawer_adatper = NULL;
私人布尔mDrawerState = FALSE;
私人VideoAdapter适配器;
@覆盖
保护无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
的setContentView（R.layout.activity_main）;
ButterKnife.inject（本）;
请求队列排队= Volley.newRequestQueue（本）;
字符串URL = Globals.getHostAddress（）+/ get_latest_video;
items.clear（）;
CacheRequest cacheRequest =新CacheRequest（0，网址，新Response.Listener＆LT; NetworkResponse＆GT;（）{
@覆盖
公共无效onResponse（NetworkResponse响应）{
尝试 {
最后弦乐jsonString =新的String（response.data，
HttpHeaderParser.parseCharset（response.headers））;
Log.e（allVideos，jsonString）;
JSONArray jsonArray =新JSONArray（jsonString）;
的for（int i = 0; I＆LT; jsonArray.length（）;我++）{
的JSONObject video_single_item = jsonArray.getJSONObject（ⅰ）;
INT VIDEO_ID = video_single_item.getInt（ID）;
字符串video_thumbnail = video_single_item.getString（缩略图）;
INT COLSPAN =的Math.random（）＆LT; 0.2F？ 2：1;
INT ROWSPAN = COLSPAN;
VideoItems项目=新VideoItems（合并单元格，行跨度，video_thumbnail，VIDEO_ID）;
items.add（项目）;
}
setUpListView（项目）;
}赶上（UnsupportedEncodingException E）{
e.printStackTrace（）;
}赶上（JSONException E）{
e.printStackTrace（）;
}
}
}，新Response.ErrorListener（）{
@覆盖
公共无效onErrorResponse（VolleyError错误）{
}
}）;
//增加请求到请求队列。
queue.add（cacheRequest）;
}
私人无效setUpListView（名单video_array_items）{
最后的名单，其中，AsymmetricItem＆GT;项目=新的ArrayList＆LT;＆GT;（）;
适配器=新VideoListAdapter（这一点，video_array_items）;
AsymmetricGridViewAdapter asymmetricAdapter =
新AsymmetricGridViewAdapter＆LT;＆GT;（这一点，ListView中，适配器）;
listView.setAdapter（asymmetricAdapter）;
listView.setRequestedColumnCount（3）;
listView.setAdapter（getNewAdapter（））;
listView.setOnItemClickListener（本）;
listView.setAllowReordering（真正的）;
listView.isAllowReordering（）;
}
私人AsymmetricGridViewAdapter＆LT;＆GT; getNewAdapter（）{
返回新AsymmetricGridViewAdapter＆LT;＆GT;（这一点，ListView中，适配器）;
}
@覆盖
公共无效onItemClick（适配器视图＆LT;＆GT;适配器视图，视图中查看，INT位置，长的id）{
INT video_position = items.get（位置）.getVideo_id（）;
意向意图=新的意图（ActivityBootstrap.this，ActivitySHowVideoDetaile.class）;
intent.putExtra（VIDEO_ID，video_position）;
startActivity（意向）;
}
}
修订POST 2）
的结果Log.e（allVideos，jsonString）; 是：
九月10号至28日：51：46.016 17872-17872 / pishguy.ir.asrebidree E / allVideos： [{"id":12,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"},{"id":10,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"}]
9月一十日日至28日：51：47.249 17872-17872 / pishguy.ir.asrebidree E / allVideos： [{"id":12,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"},{"id":10,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"}]
服务器响应的结果，我是用浏览器测试：
<$p$p><$c$c>[{"id":12,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"},{"id":10,"thumbnail":"1445615983c92d10f1f3ee907150be1fdb8184ca893178682-360p__19106.png"}]
可惜这重复的结果是随机的（不重复每次）
更新3：
10-28 13：14：52.322 16129-16129 / pishguy.ir.asrebidree E /测试：所谓的onCreate
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"}]
解决方案
由于我曾评论过多的线条，我不能再产生重复行为作为当前的问题，所以我在这里发布我的回答，希望这有助于！
在 CacheDispatcher 类，你会发现以下内容：
如果（！entry.refreshNeeded（））{
//完全过期的缓存命中。刚刚传送的响应。
mDelivery.postResponse（请求，响应）;
} 其他 {
//软过期的缓存命中。我们可以提供缓存的响应，
//但是我们还需要将请求发送到网络
//耳目一新。
request.addMarker（缓存命中刷新需要的）;
request.setCacheEntry（入口）;
//标记的响应作为中间。
response.intermediate = TRUE;
//邮政中间响应返回给用户，并有
//交付则请求跟着网络转发。
mDelivery.postResponse（请求，响应，新的可运行（）{
@覆盖
公共无效的run（）{
尝试 {
mNetworkQueue.put（要求）;
}赶上（InterruptedException异常E）{
//不多，我们可以做到这一点。
}
}
}）;
}
国际海事组织，则可能是 softTtl 是导致这种重复的行为。
我建议您使用以下行setRetryPolicy为您的要求：
cacheRequest.setRetryPolicy（新DefaultRetryPolicy（DefaultRetryPolicy.DEFAULT_TIMEOUT_MS * 2,0，DefaultRetryPolicy.DEFAULT_BACKOFF_MULT））;
//增加请求到请求队列。
queue.add（cacheRequest）;
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"}]
解决方案
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);
这篇关于Android的缓存机制返回多结果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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