Add fresh parameter :

src/com/androidquery/AbstractAQuery.java

@@ -1987,8 +1987,30 @@ public <K> T ajax(String url, Class<K> type, AjaxCallback<K> callback){
 	 */
 
 	public <K> T ajax(String url, Class<K> type, long expire, AjaxCallback<K> callback){
+		return ajax(url, type, expire, expire, callback);
+	}
+
+	/**
+	 * Ajax call with various callback data types with file caching.
+	 * 
+	 * The expire param is the duration to consider cached data expired (if hit).
+	 * For example, expire = 15 * 60 * 1000 means if the cache data is within 15 minutes old, 
+	 * return cached data immediately, otherwise go fetch the source again.
+	 * 
+	 *
+	 * @param url url
+	 * @param type data type
+	 * @param expire duration in millseconds, 0 = always use cache
+	 * @param fresh duration in millseconds, 0 = always use cache
+	 * @param callback callback handler
+	 * @return self
+	 * 
+	 * 
+	 */
+
+	public <K> T ajax(String url, Class<K> type, long expire, long fresh, AjaxCallback<K> callback){
 
-		callback.type(type).url(url).fileCache(true).expire(expire);
+		callback.type(type).url(url).fileCache(true).expire(expire, fresh);
 
 		return ajax(callback);
 	}
@@ -2020,7 +2042,6 @@ public <K> T ajax(String url, Class<K> type, Object handler, String callback){
 
 	}
 
-
 	/**
 	 * Ajax call with various callback data types with file caching.
 	 * 
@@ -2040,9 +2061,33 @@ public <K> T ajax(String url, Class<K> type, Object handler, String callback){
 	 */
 
 	public <K> T ajax(String url, Class<K> type, long expire, Object handler, String callback){
+		return ajax(url, type, expire, expire, handler, callback);
+	}
+
+
+	/**
+	 * Ajax call with various callback data types with file caching.
+	 * 
+	 * The expire param is the duration to consider cache data expired (if hit).
+	 * For example, expire = 15 * 60 * 1000 means if the cache data is within 15 minutes old, 
+	 * return cached data immediately, otherwise go fetch the source again.
+	 * 
+	 *
+	 * @param url url
+	 * @param type data type
+	 * @param expire duration in millseconds, 0 = always use cache
+	 * @param fresh duration in millseconds, 0 = always use cache
+	 * @param handler the handler object with the callback method to be called
+	 * @param callback callback method name
+	 * @return self
+	 * 
+	 * 
+	 */
+
+	public <K> T ajax(String url, Class<K> type, long expire, long fresh, Object handler, String callback){
 
 		AjaxCallback<K> cb = new AjaxCallback<K>();
-		cb.type(type).weakHandler(handler, callback).fileCache(true).expire(expire);
+		cb.type(type).weakHandler(handler, callback).fileCache(true).expire(expire, fresh);
 
 		return ajax(url, type, cb);
 	}
@@ -2200,8 +2245,6 @@ public <K> T sync(AjaxCallback<K> callback){
 		return self();
 	}
 
-
-
 	/**
 	 * Cache the url to file cache without any callback.
 	 *
@@ -2214,7 +2257,23 @@ public <K> T sync(AjaxCallback<K> callback){
 	 * @see testCache
 	 */
 	public T cache(String url, long expire){		
-		return ajax(url, byte[].class, expire, null, null);		
+		return cache(url, expire, expire);
+	}
+
+	/**
+	 * Cache the url to file cache without any callback.
+	 *
+	 *
+	 * @param url url to cache
+	 * @param expire duration in millseconds, 0 = never consider cached data as expired
+	 * @param fresh duration in millseconds, 0 = never consider cached data as expired
+	 * 
+	 * @return self
+	 * 
+	 * @see testCache
+	 */
+	public T cache(String url, long expire, long fresh){		
+		return ajax(url, byte[].class, expire, fresh, null, null);		
 	}
 
 

src/com/androidquery/callback/AbstractAjaxCallback.java

@@ -148,6 +148,7 @@ public abstract class AbstractAjaxCallback<T, K> implements Runnable{
 	private boolean redirect = true;
 
 	private long expire;
+	private long fresh;
 	private String encoding = "UTF-8";
 	private WeakReference<Activity> act;
 
@@ -395,6 +396,22 @@ public K uiCallback(boolean uiCallback){
 	 */
 	public K expire(long expire){
 		this.expire = expire;
+		this.fresh = expire;
+		return self();
+	}
+
+	/**
+	 * The expire and fresh duation for filecache. 
+	 * If a cached copy will be served if a cached file exists within current time minus fresh duration.
+	 * But, with network error case and if a cached copy will be served if a cached file exists within current time minus expire duration
+	 *
+	 * @param expire the expire
+	 * @param fresh the fresh
+	 * @return self
+	 */
+	public K expire(long expire, long fresh){
+		this.expire = expire;
+		this.fresh = fresh;
 		return self();
 	}
 
@@ -911,15 +928,17 @@ protected void filePut(String url, T object, File file, byte[] data){
 
 	}
 
-	protected File accessFile(File cacheDir, String url){	
+	protected File accessFile(File cacheDir, String url, boolean onlyFresh){	
 
 		if(expire < 0) return null;
 
+		long limit = onlyFresh ? fresh : expire;
+
 		File file = AQUtility.getExistedCacheByUrl(cacheDir, url);
 
 		if(file != null && expire != 0){
 			long diff = System.currentTimeMillis() - file.lastModified();	
-			if(diff > expire){
+			if(diff > limit){
 				return null;
 			}
 		}
@@ -1072,11 +1091,9 @@ public void run() {
 	}
 
 	private void backgroundWork(){
-
 		if(!refresh){
-
 			if(fileCache){	
-				fileWork();			
+				fileWork(true);			
 			}
 		}
 
@@ -1088,7 +1105,16 @@ private void backgroundWork(){
 			networkWork();
 		}
 
-
+		if(result == null && !refresh && fileCache){
+			AjaxStatus prevStatus = status;
+			status = new AjaxStatus();
+
+			fileWork(false);
+
+			if (result == null){
+				status = prevStatus;
+			}
+		}
 	}
 
 	private String getCacheUrl(){
@@ -1113,9 +1139,9 @@ private String getNetworkUrl(String url){
 		return result;
 	}
 
-	private void fileWork(){
+	private void fileWork(boolean freshOnly){
 
-		File file = accessFile(cacheDir, getCacheUrl());
+		File file = accessFile(cacheDir, getCacheUrl(), freshOnly);
 
 		//if file exist
 		if(file != null){

src/com/androidquery/callback/BitmapAjaxCallback.java

@@ -450,13 +450,13 @@ private Bitmap bmGet(String path, byte[] data){
     }
 
     @Override
-    protected File accessFile(File cacheDir, String url){		
+    protected File accessFile(File cacheDir, String url, boolean onlyFresh){		
 
     	if(imageFile != null && imageFile.exists()){
     		return imageFile;
     	}
 
-		return super.accessFile(cacheDir, url);
+		return super.accessFile(cacheDir, url, onlyFresh);
 	}