[gnome-maps/wip/mlundblad/night-mode: 2/3] application: Add action for toggling night mode

[Marcus Lundblad <mlundblad src gnome org>]

commit 7228fee38540aecf082cee923833fa7bdb06cbb8
Author: Marcus Lundblad <ml update uu se>
Date:   Tue Jun 2 22:35:06 2020 +0200

    application: Add action for toggling night mode

 src/application.js | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
---
diff --git a/src/application.js b/src/application.js
index ab2252e6..4acef4d4 100644
--- a/src/application.js
+++ b/src/application.js
@@ -225,6 +225,12 @@ var Application = GObject.registerClass({
         }
     }
 
+    _onNightModeChange(action) {
+        let state = action.get_state();
+        let gtkSettings = Gtk.Settings.get_default();
+        gtkSettings.gtk_application_prefer_dark_theme = state.get_boolean();
+    }
+
     vfunc_startup() {
         super.vfunc_startup();
 
@@ -243,12 +249,23 @@ var Application = GObject.registerClass({
             'osm-account-setup': {
                 onActivate: this._onOsmAccountSetupActivate.bind(this)
             },
+            'night-mode': {
+                paramType:     'b',
+                onChangeState: this._onNightModeChange.bind(this),
+                setting:       'night-mode'
+            },
             'quit': {
                 onActivate: () => this.quit(),
                 accels: ['<Primary>Q']
             }
         });
 
+        // set dark theme when night-mode is enabled
+        let gtkSettings = Gtk.Settings.get_default();
+
+        gtkSettings.gtk_application_prefer_dark_theme =
+            settings.get('night-mode');
+
         Gtk.IconTheme.get_default().append_search_path(GLib.build_filenamev([pkg.pkgdatadir,
                                                                              'icons']));
         this._initPlaceStore();