Cache WeakReferences to our box art bitmaps after LRU evictions

app/src/main/java/com/limelight/grid/assets/MemoryAssetLoader.java

@@ -5,6 +5,9 @@ import android.util.LruCache;
 
 import com.limelight.LimeLog;
 
+import java.lang.ref.WeakReference;
+import java.util.HashMap;
+
 public class MemoryAssetLoader {
     private static final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
     private static final LruCache<String, Bitmap> memoryCache = new LruCache<String, Bitmap>(maxMemory / 16) {
@@ -13,18 +16,51 @@ public class MemoryAssetLoader {
             // Sizeof returns kilobytes
             return bitmap.getByteCount() / 1024;
         }
+
+        @Override
+        protected void entryRemoved(boolean evicted, String key, Bitmap oldValue, Bitmap newValue) {
+            super.entryRemoved(evicted, key, oldValue, newValue);
+
+            if (evicted) {
+                // Keep a weak reference around to the bitmap as long as we can
+                evictionCache.put(key, new WeakReference<>(oldValue));
+            }
+        }
     };
+    private static final HashMap<String, WeakReference<Bitmap>> evictionCache = new HashMap<>();
 
     private static String constructKey(CachedAppAssetLoader.LoaderTuple tuple) {
         return tuple.computer.uuid+"-"+tuple.app.getAppId();
     }
 
     public Bitmap loadBitmapFromCache(CachedAppAssetLoader.LoaderTuple tuple) {
-        Bitmap bmp = memoryCache.get(constructKey(tuple));
+        final String key = constructKey(tuple);
+
+        Bitmap bmp = memoryCache.get(key);
         if (bmp != null) {
-            LimeLog.info("Memory cache hit for tuple: "+tuple);
+            LimeLog.info("LRU cache hit for tuple: "+tuple);
+            return bmp;
         }
-        return bmp;
+
+        WeakReference<Bitmap> bmpRef = evictionCache.get(key);
+        if (bmpRef != null) {
+            bmp = bmpRef.get();
+            if (bmp != null) {
+                LimeLog.info("Eviction cache hit for tuple: "+tuple);
+
+                // Put this entry back into the LRU cache
+                evictionCache.remove(key);
+                memoryCache.put(key, bmp);
+
+                return bmp;
+            }
+            else {
+                // The data is gone, so remove the dangling WeakReference now
+                evictionCache.remove(key);
+            }
+        }
+
+        return null;
     }
 
     public void populateCache(CachedAppAssetLoader.LoaderTuple tuple, Bitmap bitmap) {
@@ -32,6 +68,8 @@ public class MemoryAssetLoader {
     }
 
     public void clearCache() {
+        // We must evict first because that will push all items into the eviction cache
         memoryCache.evictAll();
+        evictionCache.clear();
     }
 }