Add template for a preferences dialog

src/Makefile.am

@@ -21,6 +21,7 @@ gg-resources.c: $(res_src) $(resource_files)
 VALA_SOURCES = \
 	gg-application.vala \
 	gg-window.vala \
+	gg-preferences.vala \
 	gg-main.vala
 
 gnome_gitlab_SOURCES = \

src/gg-application.vala

@@ -8,6 +8,7 @@ namespace GnomeGitlab
         };
 
         const GLib.ActionEntry[] action_entries = {
+            { "preferences", on_preferences_activate },
             { "quit", on_quit_activate }
         };
 
@@ -59,5 +60,12 @@ namespace GnomeGitlab
         {
             quit ();
         }
+
+        void on_preferences_activate ()
+        {
+            Preferences.show ((Window)get_active_window ());
+
+            return;
+        }
     }
 }

src/gg-preferences.vala

@@ -0,0 +1,28 @@
+namespace GnomeGitlab
+{
+    [GtkTemplate (ui = "/eu/polonkai/gergely/gnome-gitlab/ui/gg-preferences.ui")]
+
+    public class Preferences : Gtk.Dialog
+    {
+        private static GLib.Once<Preferences> instance;
+
+        private Preferences () {
+            response.connect (() => {
+                hide ();
+            });
+        }
+
+        public static void show (Window parent)
+        {
+            Preferences inst;
+
+            inst = instance.once (() => { return new Preferences (); });
+
+            if (parent != inst.get_transient_for ()) {
+                inst.set_transient_for (parent);
+            }
+
+            inst.present ();
+        }
+    }
+}

src/resources/gnome-gitlab.gresource.xml

@@ -2,5 +2,6 @@
 <gresources>
   <gresource prefix="/eu/polonkai/gergely/gnome-gitlab">
     <file>ui/gg-window.ui</file>
+    <file>ui/gg-preferences.ui</file>
   </gresource>
 </gresources>

src/resources/ui/gg-preferences.ui

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <requires lib="gtk+" version="3.12"/>
+  <template class="GnomeGitlabPreferences" parent="GtkDialog">
+    <property name="title" translatable="yes">Preferences</property>
+    <property name="type_hint">normal</property>
+    <property name="can_focus">False</property>
+    <child internal-child="vbox">
+      <object class="GtkBox">
+        <child>
+          <object class="GtkLabel">
+            <property name="visible">True</property>
+            <property name="label">Preferences dialog</property>
+          </object>
+        </child>
+      </object>
+    </child>
+  </template>
+</interface>

src/resources/ui/gg-window.ui

@@ -38,6 +38,16 @@
                     <property name="fill">True</property>
                   </packing>
                 </child>
+                <child>
+                  <object class="GtkButton">
+                    <property name="label" translatable="yes">Manage GitLab instances</property>
+                    <property name="action_name">app.preferences</property>
+                  </object>
+                  <packing>
+                    <property name="expand">False</property>
+                    <property name="fill">False</property>
+                  </packing>
+                </child>
               </object>
               <packing>
                 <property name="name">no-instances</property>