[gnome-music/wip/mschraal/gtk4-toasts: 1/2] Use progressbar for loading indicator

[Marinus Schraal <mschraal src gnome org>]

commit 5bd4b7322eb84171457aecddfa72c6b9077070e9
Author: Marinus Schraal <mschraal gnome org>
Date:   Tue Feb 15 12:39:37 2022 +0100

    Use progressbar for loading indicator
    
    Drop the notification use.

 data/org.gnome.Music.gresource.xml       |  1 -
 data/ui/LoadingNotification.ui           | 18 --------
 data/ui/Window.ui                        |  9 ++++
 gnomemusic/notificationmanager.py        | 30 ++++++++-----
 gnomemusic/widgets/notificationspopup.py | 72 +-------------------------------
 gnomemusic/window.py                     | 18 ++++++++
 po/POTFILES.in                           |  1 -
 7 files changed, 48 insertions(+), 101 deletions(-)
---
diff --git a/data/org.gnome.Music.gresource.xml b/data/org.gnome.Music.gresource.xml
index d7f26d177..af573f539 100644
--- a/data/org.gnome.Music.gresource.xml
+++ b/data/org.gnome.Music.gresource.xml
@@ -18,7 +18,6 @@
     <file preprocess="xml-stripblanks">ui/EmptyView.ui</file>
     <file preprocess="xml-stripblanks">ui/HeaderBar.ui</file>
     <file preprocess="xml-stripblanks">ui/LastfmDialog.ui</file>
-    <file preprocess="xml-stripblanks">ui/LoadingNotification.ui</file>
     <file preprocess="xml-stripblanks">ui/NotificationsPopup.ui</file>
     <file preprocess="xml-stripblanks">ui/PlayerToolbar.ui</file>
     <file preprocess="xml-stripblanks">ui/PlaylistControls.ui</file>
diff --git a/data/ui/Window.ui b/data/ui/Window.ui
index 92052f1bd..e767ae0cd 100644
--- a/data/ui/Window.ui
+++ b/data/ui/Window.ui
@@ -27,6 +27,15 @@
                 <property name="vhomogeneous">False</property>
               </object>
             </child>
+            <child type="overlay">
+              <object class="GtkProgressBar" id="_loading_progress">
+                <property name="valign">start</property>
+                <property name="visible">False</property>
+                <style>
+                  <class name="osd"/>
+                </style>
+              </object>
+            </child>
             <child type="overlay">
               <object class="NotificationsPopup" id="notifications_popup">
                 <property name="halign">center</property>
diff --git a/gnomemusic/notificationmanager.py b/gnomemusic/notificationmanager.py
index 6ffee620c..5ea0520e5 100644
--- a/gnomemusic/notificationmanager.py
+++ b/gnomemusic/notificationmanager.py
@@ -22,13 +22,16 @@
 # code, but you are not obligated to do so.  If you do not wish to do so,
 # delete this exception statement from your version.
 
-from gi.repository import GObject
+from gi.repository import GLib, GObject
 
 
 class NotificationManager(GObject.Object):
     """Managing wrapper around the notification widgets
     """
 
+    _pulse_id = 0
+    _loading_counter = 0
+
     def __init__(self, application):
         """Initialize the notification manager
 
@@ -37,7 +40,6 @@ class NotificationManager(GObject.Object):
         super().__init__()
 
         self._application = application
-        self._pushed = False
         self._window = application.props.window
 
         if self._window is None:
@@ -46,16 +48,24 @@ class NotificationManager(GObject.Object):
 
     def _on_window_changed(self, klass, value):
         self._window = self._application.props.window
+        if self._loading_counter > 0:
+            self._window.loading_visible(True)
 
     def push_loading(self):
         """Push a loading notifcation."""
-        if self._window:
-            # This makes sure push/pop are in sync when starting.
-            self._pushed = True
-            self._window.notifications_popup.push_loading()
+        self._loading_counter += 1
+
+        if (self._pulse_id == 0
+                and self._window):
+            self._window.loading_visible(True)
+            self._pulse_id = GLib.timeout_add(100, self._window.loading_pulse)
 
     def pop_loading(self):
-        """Pop a loading notification."""
-        if (self._window
-                and self._pushed):
-            self._window.notifications_popup.pop_loading()
+        self._loading_counter -= 1
+
+        if (self._loading_counter == 0
+                and self._pulse_id != 0):
+            GLib.Source.remove(self._pulse_id)
+            self._pulse_id = 0
+            if self._window:
+                self._window.loading_visible(False)
diff --git a/gnomemusic/widgets/notificationspopup.py b/gnomemusic/widgets/notificationspopup.py
index f18e48b66..1068f50fc 100644
--- a/gnomemusic/widgets/notificationspopup.py
+++ b/gnomemusic/widgets/notificationspopup.py
@@ -44,15 +44,9 @@ class NotificationsPopup(Gtk.Revealer):
     def __init__(self):
         super().__init__()
 
-        self._loading_notification = LoadingNotification()
-        self._loading_notification.connect('visible', self._set_visibility)
-        self._loading_notification.connect('invisible', self._set_visibility)
-        self._box.append(self._loading_notification)
-
     def _hide_notifications(self, notification, remove):
         if remove:
             self._box.remove(notification)
-        self._loading_notification.hide()
         self.hide()
 
     def _set_visibility(self, notification, remove=False):
@@ -61,12 +55,8 @@ class NotificationsPopup(Gtk.Revealer):
         Popup is displayed if a loading is active or if a playlist
         deletion is in progress.
         """
-        loading_finished = self._loading_notification._counter == 0
         box_children = [child for child in self._box]
-        no_other_notif = (len(box_children) == 1
-                          or (len(box_children) == 2
-                              and notification != self._loading_notification))
-        invisible = loading_finished and no_other_notif
+        invisible = (len(box_children) == 1 or (len(box_children) == 2))
 
         if not invisible:
             if remove:
@@ -80,20 +70,6 @@ class NotificationsPopup(Gtk.Revealer):
                 duration + 100, self._hide_notifications, notification, remove)
         self.set_reveal_child(not invisible)
 
-    def pop_loading(self):
-        """Decrease loading notification counter.
-
-        If it reaches zero, the notification is withdrawn.
-        """
-        self._loading_notification.pop()
-
-    def push_loading(self):
-        """Increase loading notification counter.
-
-        If no notification is visible, start loading notification.
-        """
-        self._loading_notification.push()
-
     def add_notification(self, notification):
         """Display a new notification
 
@@ -118,52 +94,6 @@ class NotificationsPopup(Gtk.Revealer):
                 notification._finish_deletion()
 
 
-@Gtk.Template(resource_path="/org/gnome/Music/ui/LoadingNotification.ui")
-class LoadingNotification(Gtk.Grid):
-    """LoadingNotification displays a loading notification message
-
-    It can be triggered by different all main views. Message is
-    displayed as long as at least one loading operation is in progress.
-    """
-
-    __gsignals__ = {
-        'visible': (GObject.SignalFlags.RUN_FIRST, None, ()),
-        'invisible': (GObject.SignalFlags.RUN_FIRST, None, ())
-    }
-
-    __gtype_name__ = "LoadingNotification"
-
-    def __init__(self):
-        super().__init__()
-        self._counter = 0
-        self._timeout_id = 0
-
-    def pop(self):
-        """Decrease the counter. Hide notification if it reaches 0."""
-        self._counter = self._counter - 1
-
-        if self._counter == 0:
-            # Stop the timeout if necessary
-            if self._timeout_id > 0:
-                if not self.is_visible():
-                    GLib.source_remove(self._timeout_id)
-                self._timeout_id = 0
-            self.emit('invisible')
-
-    def push(self):
-        """Increase the counter. Start notification if necessary."""
-        def callback():
-            self.props.visible = True
-            self.emit('visible')
-
-        if self._counter == 0:
-            # Only show the notification after a small delay, thus
-            # add a timeout. 500ms feels good enough.
-            self._timeout_id = GLib.timeout_add(500, callback)
-
-        self._counter = self._counter + 1
-
-
 @Gtk.Template(resource_path="/org/gnome/Music/ui/PlaylistNotification.ui")
 class PlaylistNotification(Gtk.Grid):
     """Show a notification on playlist or song deletion.
diff --git a/gnomemusic/window.py b/gnomemusic/window.py
index a79753817..fedbd9203 100644
--- a/gnomemusic/window.py
+++ b/gnomemusic/window.py
@@ -58,6 +58,7 @@ class Window(Adw.ApplicationWindow):
 
     notifications_popup = Gtk.Template.Child()
     _headerbar_stack = Gtk.Template.Child()
+    _loading_progress = Gtk.Template.Child()
     _overlay = Gtk.Template.Child()
     _player_toolbar = Gtk.Template.Child()
     _selection_toolbar = Gtk.Template.Child()
@@ -477,3 +478,20 @@ class Window(Adw.ApplicationWindow):
         :param bool visible: actionbar visibility
         """
         self._player_toolbar.props.revealed = visible
+
+    def loading_pulse(self) -> bool:
+        """Pulse the loading progress bar
+
+        :returns: GLib.SOURCE_CONTINUE
+        :rtype: bool
+        """
+        self._loading_progress.pulse()
+
+        return GLib.SOURCE_CONTINUE
+
+    def loading_visible(self, show: bool) -> None:
+        """Sets visibility of the loading progressbar
+
+        :param bool show: Wheter to show the loading bar
+        """
+        self._loading_progress.props.visible = show
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 302fb4376..f5b2bf5d0 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -10,7 +10,6 @@ data/ui/EmptyView.ui
 data/ui/HeaderBar.ui
 data/ui/help-overlay.ui
 data/ui/LastfmDialog.ui
-data/ui/LoadingNotification.ui
 data/ui/PlayerToolbar.ui
 data/ui/PlaylistControls.ui
 data/ui/PlaylistDialog.ui