Solving bugs with the memory's garbage collector.

Opus/Code/MainActivity.cs

@@ -285,10 +285,6 @@ namespace Opus
             if(account != null)
                 Picasso.With(this).Load(account.PhotoUrl).Transform(new CircleTransformation()).Into(new AccountTarget());
 
-            var item = menu.FindItem(Resource.Id.filter);
-            var filterView = item.ActionView.JavaCast<SearchView>();
-            filterView.QueryTextChange += Search;
-            item.SetVisible(false);
             menu.FindItem(Resource.Id.search).SetOnActionExpandListener(this);
             ((SearchView)menu.FindItem(Resource.Id.search).ActionView).SetOnQueryTextFocusChangeListener(this);
             ((SearchView)menu.FindItem(Resource.Id.search).ActionView).QueryHint = GetString(Resource.String.youtube_search);
@@ -297,6 +293,23 @@ namespace Opus
             return base.OnCreateOptionsMenu(menu);
         }
 
+        public void AddFilterListener(EventHandler<SearchView.QueryTextChangeEventArgs> textChanged)
+        {
+            if (menu == null)
+                return;
+
+            var item = menu.FindItem(Resource.Id.filter);
+            var filterView = item.ActionView.JavaCast<SearchView>();
+            filterView.QueryTextChange += textChanged;
+        }
+
+        public void RemoveFilterListener(EventHandler<SearchView.QueryTextChangeEventArgs> textChanged)
+        {
+            var item = menu.FindItem(Resource.Id.filter);
+            var filterView = item.ActionView.JavaCast<SearchView>();
+            filterView.QueryTextChange -= textChanged;
+        }
+
         public override bool OnOptionsItemSelected(IMenuItem item)
         {
             if(item.ItemId == Android.Resource.Id.Home)
@@ -348,16 +361,6 @@ namespace Opus
             return true;
         }
 
-        void Search(object sender, SearchView.QueryTextChangeEventArgs e)
-        {
-            if (Browse.instance != null)
-                Browse.instance.Search(e.NewText);
-            if (PlaylistTracks.instance != null)
-                PlaylistTracks.instance.Search(e.NewText);
-            if (FolderTracks.instance != null)
-                FolderTracks.instance.Search(e.NewText);
-        }
-
         public void OnFocusChange(View v, bool hasFocus)
         {
             if (hasFocus)

Opus/Code/UI/Fragments/Browse.cs

@@ -34,12 +34,14 @@ namespace Opus.Fragments
         {
             base.OnActivityCreated(savedInstanceState);
             MainActivity.instance.contentRefresh.Refresh += OnRefresh;
+            MainActivity.instance.AddFilterListener(Search);
             ListView.NestedScrollingEnabled = true;
         }
 
         public override void OnDestroy()
         {
             MainActivity.instance.contentRefresh.Refresh -= OnRefresh;
+            MainActivity.instance.RemoveFilterListener(Search);
             base.OnDestroy();
             instance = null;
         }
@@ -138,12 +140,12 @@ namespace Opus.Fragments
             adapter.NotifyDataSetChanged();
         }
 
-        public void Search(string search)
+        public void Search(object sender, Android.Support.V7.Widget.SearchView.QueryTextChangeEventArgs e)
         {
-            if (search == "")
+            if (e.NewText == "")
                 query = null;
             else
-                query = search;
+                query = e.NewText;
 
             LoaderManager.GetInstance(this).RestartLoader(0, null, this);
         }

Opus/Code/UI/Fragments/FolderTracks.cs

@@ -34,6 +34,7 @@ namespace Opus.Fragments
         {
             base.OnActivityCreated(savedInstanceState);
             MainActivity.instance.contentRefresh.Refresh += OnRefresh;
+            MainActivity.instance.AddFilterListener(Search);
 
             MainActivity.instance.SupportActionBar.SetDisplayShowTitleEnabled(true);
             MainActivity.instance.FindViewById(Resource.Id.toolbarLogo).Visibility = ViewStates.Gone;
@@ -42,6 +43,7 @@ namespace Opus.Fragments
 
         public override void OnDestroy()
         {
+            MainActivity.instance.RemoveFilterListener(Search);
             MainActivity.instance.contentRefresh.Refresh -= OnRefresh;
             instance = null;
             base.OnDestroy();
@@ -125,12 +127,12 @@ namespace Opus.Fragments
             adapter.NotifyDataSetChanged();
         }
 
-        public void Search(string search)
+        public void Search(object sender, Android.Support.V7.Widget.SearchView.QueryTextChangeEventArgs e)
         {
-            if (search == "")
+            if (e.NewText == "")
                 query = null;
             else
-                query = search;
+                query = e.NewText;
 
             LoaderManager.GetInstance(this).RestartLoader(0, null, this);
         }

Opus/Code/UI/Fragments/PlaylistTracks.cs

@@ -19,6 +19,7 @@ using CursorLoader = Android.Support.V4.Content.CursorLoader;
 using PlaylistItem = Opus.DataStructure.PlaylistItem;
 using PopupMenu = Android.Support.V7.Widget.PopupMenu;
 using RecyclerView = Android.Support.V7.Widget.RecyclerView;
+using SearchView = Android.Support.V7.Widget.SearchView;
 using Toolbar = Android.Support.V7.Widget.Toolbar;
 
 namespace Opus.Fragments
@@ -46,7 +47,14 @@ namespace Opus.Fragments
         public override void OnActivityCreated(Bundle savedInstanceState)
         {
             base.OnActivityCreated(savedInstanceState);
+            if(item == null)
+            {
+                MainActivity.instance.SupportFragmentManager.PopBackStack();
+                return;
+            }
+
             MainActivity.instance.contentRefresh.Refresh += OnRefresh;
+            MainActivity.instance.AddFilterListener(Search);
             MainActivity.instance.DisplaySearch();
 
             MainActivity.instance.SupportActionBar.SetHomeButtonEnabled(true);
@@ -67,7 +75,7 @@ namespace Opus.Fragments
 #pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
             PopulateList();
 #pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
-            if(useHeader)
+            if(useHeader && item != null)
                 CreateHeader();
             //if (item.SyncState == SyncState.Error)
             //    CreateSyncBanner();
@@ -127,6 +135,7 @@ namespace Opus.Fragments
 
         public override void OnDestroyView()
         {
+            MainActivity.instance.RemoveFilterListener(Search);
             Activity.FindViewById<ImageButton>(Resource.Id.headerPlay).Click -= HeaderPlay;
             Activity.FindViewById<ImageButton>(Resource.Id.headerShuffle).Click -= HeaderShuffle;
             Activity.FindViewById<ImageButton>(Resource.Id.headerMore).Click -= PlaylistMore;
@@ -253,6 +262,7 @@ namespace Opus.Fragments
             instance.item = new PlaylistItem() { Name = playlistName, Count = songs.Count, HasWritePermission = false, LocalID = -1, YoutubeID = null };
             instance.useHeader = false;
             instance.fullyLoadded = true;
+            instance.isInEditMode = false;
             instance.adapter = new PlaylistTrackAdapter(new SearchableList<Song>(songs));
             return instance;
         }
@@ -262,6 +272,7 @@ namespace Opus.Fragments
             instance = new PlaylistTracks { Arguments = new Bundle() };
             instance.item = item;
             instance.useHeader = true;
+            instance.isInEditMode = true;
             instance.fullyLoadded = item.LocalID != 0 && item.LocalID != -1;
 
             Task.Run(async () =>
@@ -437,12 +448,12 @@ namespace Opus.Fragments
                 LoadMore();
         }
 
-        public void Search(string search)
+        public void Search(object sender, SearchView.QueryTextChangeEventArgs e)
         {
-            if (search == "")
+            if (e.NewText == "")
                 query = null;
             else
-                query = search.ToLower();
+                query = e.NewText.ToLower();
 
             if(item.LocalID != -1)
                 LoaderManager.GetInstance(this).RestartLoader(0, null, this);

Opus/Resources/menu/toolbar_menu.xml

@@ -12,6 +12,7 @@
     android:id="@+id/filter"
     android:icon="@drawable/Filter"
     android:title="@string/filter"
+    android:visible="false"
     app:showAsAction="always|collapseActionView"
     app:actionViewClass="android.support.v7.widget.SearchView" />
   <item