[gnome-music/wip/jfelder/albumsview-selection-mode-launch: 4/5] artistsview: Correctly select the first artist on launch

[Jean Felder <jfelder src gnome org>]

commit 5804f9b5fdfb85dba3c50dbe1e04164b0b4fbd55
Author: Jean Felder <jfelder src gnome org>
Date:   Tue Mar 24 16:32:11 2020 +0100

    artistsview: Correctly select the first artist on launch
    
    On some setups (mostly flatpak), the first artist from the
    ArtistsView's sidebar may not be selected on launch.
    Indeed, it relies on listening to the artists-loaded signal from the
    CoreModel to select the first artist once the artists model is
    loaded. However, this signal may already have been emitted when the
    ArtistView is built. In that case, the first artist will never be
    selected.
    
    Now, ArtistsView instead directly listens to the artists model for
    changes and uses an initial state variable (untouched_list) to check
    if it is needed to activate a row.
    
    The artists-loaded signal from CoreModel is now unused. It can be
    removed.

 gnomemusic/coremodel.py                       |  1 -
 gnomemusic/grilowrappers/grltrackerwrapper.py |  1 -
 gnomemusic/views/artistsview.py               | 40 +++++++++++++++++----------
 3 files changed, 25 insertions(+), 17 deletions(-)
---
diff --git a/gnomemusic/coremodel.py b/gnomemusic/coremodel.py
index e5372662..185413df 100644
--- a/gnomemusic/coremodel.py
+++ b/gnomemusic/coremodel.py
@@ -65,7 +65,6 @@ class CoreModel(GObject.GObject):
     """
 
     __gsignals__ = {
-        "artists-loaded": (GObject.SignalFlags.RUN_FIRST, None, ()),
         "playlist-loaded": (GObject.SignalFlags.RUN_FIRST, None, (int,)),
         "smart-playlist-change": (GObject.SignalFlags.RUN_FIRST, None, ())
     }
diff --git a/gnomemusic/grilowrappers/grltrackerwrapper.py b/gnomemusic/grilowrappers/grltrackerwrapper.py
index 22e7796f..64616412 100644
--- a/gnomemusic/grilowrappers/grltrackerwrapper.py
+++ b/gnomemusic/grilowrappers/grltrackerwrapper.py
@@ -499,7 +499,6 @@ class GrlTrackerWrapper(GObject.GObject):
             if not media:
                 self._artists_model.splice(
                     self._artists_model.get_n_items(), 0, artists_added)
-                self._coremodel.emit("artists-loaded")
                 self._window.notifications_popup.pop_loading()
                 return
 
diff --git a/gnomemusic/views/artistsview.py b/gnomemusic/views/artistsview.py
index a5454ae5..1affa140 100644
--- a/gnomemusic/views/artistsview.py
+++ b/gnomemusic/views/artistsview.py
@@ -53,16 +53,21 @@ class ArtistsView(BaseView):
         self._artists = {}
 
         self._selected_artist = None
+        self._loaded_artists = []
+
+        # This indicates if the current list has been empty and has
+        # had no user interaction since.
+        self._untouched_list = True
 
         self._window = application.props.window
         self._coremodel = application.props.coremodel
         self._model = self._coremodel.props.artists_sort
 
+        self._sidebar.bind_model(self._model, self._create_widget)
+
         self._model.connect_after(
             "items-changed", self._on_model_items_changed)
-        self._sidebar.bind_model(self._model, self._create_widget)
-        self._loaded_id = self._coremodel.connect(
-            "artists-loaded", self._on_artists_loaded)
+        self._on_model_items_changed(self._model, 0, 0, 0)
 
         sidebar_container.props.width_request = 220
         sidebar_container.get_style_context().add_class('sidebar')
@@ -74,7 +79,6 @@ class ArtistsView(BaseView):
         self._ctrl.props.button = Gdk.BUTTON_PRIMARY
         self._ctrl.connect("released", self._on_sidebar_clicked)
 
-        self._loaded_artists = []
         self._loading_id = 0
 
         self.show_all()
@@ -88,6 +92,18 @@ class ArtistsView(BaseView):
         return row
 
     def _on_model_items_changed(self, model, position, removed, added):
+        if model.get_n_items() == 0:
+            self._untouched_list = True
+            return
+        elif self._untouched_list is True:
+            first_row = self._sidebar.get_row_at_index(0)
+            if first_row is None:
+                return
+
+            self._sidebar.select_row(first_row)
+            self._on_artist_activated(self._sidebar, first_row, True)
+            return
+
         if removed == 0:
             return
 
@@ -107,20 +123,11 @@ class ArtistsView(BaseView):
                         or self._sidebar.get_row_at_index(position - 1))
             if row_next:
                 self._sidebar.select_row(row_next)
-                self._on_artist_activated(self._sidebar, row_next)
+                self._on_artist_activated(self._sidebar, row_next, True)
 
         removed_frame = self._view.get_child_by_name(removed_artist)
         self._view.remove(removed_frame)
 
-    def _on_artists_loaded(self, klass):
-        self._coremodel.disconnect(self._loaded_id)
-        first_row = self._sidebar.get_row_at_index(0)
-        if first_row is None:
-            return
-
-        self._sidebar.select_row(first_row)
-        self._on_artist_activated(self._sidebar, first_row)
-
     def _setup_view(self):
         self._view_container = Gtk.ScrolledWindow(hexpand=True, vexpand=True)
         self._box.pack_start(self._view_container, True, True, 0)
@@ -130,7 +137,7 @@ class ArtistsView(BaseView):
             vhomogeneous=False)
         self._view_container.add(self._view)
 
-    def _on_artist_activated(self, sidebar, row, data=None):
+    def _on_artist_activated(self, sidebar, row, data=None, untouched=False):
         """Initializes new artist album widgets"""
         # On application start the first row of ArtistView is activated
         # to show an intial artist. When this happens while any of the
@@ -143,6 +150,9 @@ class ArtistsView(BaseView):
             row.props.selected = not row.props.selected
             return
 
+        if untouched is False:
+            self._untouched_list = False
+
         selected_row = self._sidebar.get_selected_row()
         self._selected_artist = selected_row.props.coreartist