Remove model observer on destroy

app/src/main/java/eu/faircode/email/ViewModelMessages.java

@@ -60,17 +60,15 @@ public class ViewModelMessages extends ViewModel {
             String query, boolean server) {
 
         Args args = new Args(context, account, folder, thread, id, query, server);
-        Log.i("Get model " + viewType + " " + args);
+        Log.i("Get model=" + viewType + " " + args);
         dump();
 
         Model model = models.get(viewType);
         if (model == null || !model.args.equals(args)) {
-            Log.i("Creating model");
+            Log.i("Creating model=" + viewType + " replace=" + (model != null));
 
-            if (model != null) {
+            if (model != null)
                 model.clear();
-                model.list.removeObservers(owner);
-            }
 
             DB db = DB.getInstance(context);
 
@@ -149,6 +147,15 @@ public class ViewModelMessages extends ViewModel {
             model = new Model(args, builder.build(), boundary);
             models.put(viewType, model);
 
+            if (viewType != AdapterMessage.ViewType.THREAD)
+                // Keep list up-to-date for previous/next navigation
+                model.list.observeForever(new Observer<PagedList<TupleMessageEx>>() {
+                    @Override
+                    public void onChanged(PagedList<TupleMessageEx> messages) {
+                    }
+                });
+        }
+
         owner.getLifecycle().addObserver(new LifecycleObserver() {
             @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
             public void onDestroyed() {
@@ -158,11 +165,17 @@ public class ViewModelMessages extends ViewModel {
                 int free_mb = Helper.getFreeMemMb();
                 boolean lowmem = (free_mb < LOW_MEM_MB);
 
-                    Log.i("Destroy model " + viewType +
+                Log.i("Destroy model=" + viewType +
                         " cache=" + cache + " lowmem=" + lowmem + " free=" + free_mb + " MB");
 
+                Model model = models.get(viewType);
+                if (model != null) {
+                    Log.i("Remove observer model=" + viewType);
+                    model.list.removeObservers(owner);
+                }
+
                 if (viewType == AdapterMessage.ViewType.THREAD || !cache || lowmem) {
-                        Log.i("Remove model " + viewType);
+                    Log.i("Remove model=" + viewType);
                     remove(viewType);
                 }
 
@@ -170,15 +183,6 @@ public class ViewModelMessages extends ViewModel {
             }
         });
 
-            if (viewType != AdapterMessage.ViewType.THREAD)
-                // Keep list up-to-date for previous/next navigation
-                model.list.observeForever(new Observer<PagedList<TupleMessageEx>>() {
-                    @Override
-                    public void onChanged(PagedList<TupleMessageEx> messages) {
-                    }
-                });
-        }
-
         if (viewType == AdapterMessage.ViewType.UNIFIED) {
             remove(AdapterMessage.ViewType.FOLDER);
             remove(AdapterMessage.ViewType.SEARCH);