[gnome-contacts] main-windows: Add selection mode button

[Niels De Graef <nielsdg src gnome org>]

commit 5fb15863bb407c5768da51f0341a13f53b5f5307
Author: Lorenz Wildberg <lorenz wild-fisch de>
Date:   Mon Jul 19 12:25:51 2021 +0200

    main-windows: Add selection mode button
    
    On touchscreen devices you must press your finger for some seconds
    and with a mouse you must right-click on an item
    to activate selection mode.
    
    If you don't know these operations it is impossible
    to activate selection mode.
    
    Now there is a selection mode button like in all other gnome apps.
    If you click it, you go into selection mode
    and can select items with just one click.

 data/ui/contacts-main-window.ui | 25 +++++++++++++++++++++++++
 src/contacts-main-window.vala   |  8 ++++++++
 2 files changed, 33 insertions(+)
---
diff --git a/data/ui/contacts-main-window.ui b/data/ui/contacts-main-window.ui
index b5842380..ee0cfd1f 100644
--- a/data/ui/contacts-main-window.ui
+++ b/data/ui/contacts-main-window.ui
@@ -188,6 +188,30 @@
                     <property name="pack_type">start</property>
                   </packing>
                 </child>
+
+                <child>
+                  <object class="GtkButton" id="selection_button">
+                    <property name="visible">True</property>
+                    <property name="can_focus">True</property>
+                    <property name="halign">center</property>
+                    <property name="valign">center</property>
+                    <property name="tooltip_text" translatable="yes">Select Items</property>
+                    <signal name="clicked" handler="on_selection_button_clicked"/>
+                    <child>
+                      <object class="GtkImage">
+                        <property name="visible">True</property>
+                        <property name="can_focus">False</property>
+                        <property name="icon_name">object-select-symbolic</property>
+                        <property name="icon_size">1</property>
+                      </object>
+                    </child>
+                  </object>
+                  <packing>
+                    <property name="pack_type">end</property>
+                    <property name="position">2</property>
+                  </packing>
+                </child>
+
                 <child>
                   <object class="GtkMenuButton" id="hamburger_menu_button">
                     <property name="visible">True</property>
@@ -206,6 +230,7 @@
                   </object>
                   <packing>
                     <property name="pack_type">end</property>
+                    <property name="position">1</property>
                   </packing>
                 </child>
                 <child>
diff --git a/src/contacts-main-window.vala b/src/contacts-main-window.vala
index 486c16aa..0fac6017 100644
--- a/src/contacts-main-window.vala
+++ b/src/contacts-main-window.vala
@@ -66,6 +66,8 @@ public class Contacts.MainWindow : Hdy.ApplicationWindow {
   private unowned Gtk.Button cancel_button;
   [GtkChild]
   private unowned Gtk.Button done_button;
+  [GtkChild]
+  private unowned Gtk.Button selection_button;
 
   // The 2 panes the window consists of
   private ListPane list_pane;
@@ -223,6 +225,7 @@ public class Contacts.MainWindow : Hdy.ApplicationWindow {
 
     // Selecting UI
     this.select_cancel_button.visible = (this.state == UiState.SELECTING);
+    this.selection_button.visible = !(this.state == UiState.SELECTING || this.state.editing ());
 
     if (this.state != UiState.SELECTING)
       this.left_header.title = _("Contacts");
@@ -294,6 +297,11 @@ public class Contacts.MainWindow : Hdy.ApplicationWindow {
     this.contact_pane.individual.is_favourite = !is_fav;
   }
 
+  [GtkCallback]
+  private void on_selection_button_clicked () {
+    this.state = UiState.SELECTING;
+  }
+
   private void unlink_contact () {
     var individual = this.contact_pane.individual;
     if (individual == null)