feat: trim the icon cache after refreshing

android/src/main/java/org/ligi/fast/background/BaseAppGatherAsyncTask.java

@@ -50,7 +50,6 @@ protected Void doInBackground(Void... params) {
     @Override
     protected void onPostExecute(Void result) {
         App.getPackageChangedListener().onPackageChange(mChangedPackageNames, appInfoList);
-        //TODO trim icon cache
     }
 
     /**

android/src/main/java/org/ligi/fast/background/PackageChangeReceiver.java

@@ -45,7 +45,6 @@ public void onReceive(Context context, Intent intent) {
                 if (!intent.getBooleanExtra(Intent.EXTRA_REPLACING, false)) {
                     App.getPackageChangedListener().onPackageChange(Collections.singletonList(packageName), null);
                 }
-                //TODO trim icon cache
                 break;
         }
     }

android/src/main/java/org/ligi/fast/model/AppIconCache.java

@@ -6,6 +6,7 @@
 import android.graphics.Bitmap;
 import android.graphics.drawable.BitmapDrawable;
 import android.graphics.drawable.Drawable;
+import android.support.annotation.Nullable;
 
 import org.ligi.fast.App;
 import org.ligi.tracedroid.logging.Log;
@@ -14,6 +15,8 @@
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.lang.ref.SoftReference;
+import java.util.Iterator;
+import java.util.List;
 
 public class AppIconCache {
     private static final Bitmap.CompressFormat COMPRESS_FORMAT = Bitmap.CompressFormat.PNG;
@@ -56,6 +59,36 @@ public static void invalidateIconCache() {
         }
     }
 
+    /**
+     * Delete all icon cache files that are not referenced in the current app info list.
+     * If no app info list is provided all currently cached icons will be deleted.
+     *
+     * @param currentAppInfo The complete and up-to-date app info list. Treated as empty if null.
+     */
+    public static void trimIconCache(@Nullable List<AppInfo> currentAppInfo) {
+        if (App.getBaseDir().exists()) {
+            File[] iconFiles = App.getBaseDir().listFiles(pathname -> pathname.getName().endsWith(CACHE_FILE_ENDING));
+            if (iconFiles != null) {
+                next_file:
+                for (File iconFile : iconFiles) {
+                    if (currentAppInfo != null) {
+                        for (Iterator<AppInfo> iterator = currentAppInfo.iterator(); iterator.hasNext(); ) {
+                            String referencedPath = getIconCacheFile(iterator.next()).getAbsolutePath();
+                            String cachedPath = iconFile.getAbsolutePath();
+                            if (cachedPath.equals(referencedPath)) {
+                                iterator.remove();
+                                continue next_file;
+                            }
+                        }
+                    }
+                    if (!iconFile.delete()) {
+                        Log.w("Unable to delete " + iconFile.getAbsolutePath());
+                    }
+                }
+            }
+        }
+    }
+
     public void cacheIcon(ResolveInfo ri) {
         final PackageManager packageManager = ctx.getPackageManager();
 

android/src/main/java/org/ligi/fast/model/AppInfoList.java

@@ -68,5 +68,6 @@ public void onPackageChange(List<String> changedPackageNames, List<AppInfo> newA
 
         this.clear();
         this.addAll(updatedAppInfoList);
+        new Thread(() -> AppIconCache.trimIconCache(updatedAppInfoList)).start();
     }
 }

android/src/main/java/org/ligi/fast/ui/SearchActivity.java

@@ -295,7 +295,6 @@ private String getHomePackageName() {
 
     @Override
     public void onPackageChange(List<String> changedPackages, List<AppInfo> list) {
-        // TODO we should also do a cleanup of cached icons here
         runOnUiThread(() -> {
             appInfoList.getBackingAppInfoList().onPackageChange(changedPackages, list);
             configureAdapter();