[gnome-builder] meson-templates: improve gtkmm template

[Christian Hergert <chergert src gnome org>]

commit 9e90becb03b2fb7b66e2110fdaf4e7c8cf0f349a
Author: Elnee <hsoftdima gmail com>
Date:   Fri May 3 15:06:11 2019 +0300

    meson-templates: improve gtkmm template

 src/plugins/meson-templates/resources/src/main.cpp |  4 +--
 .../meson-templates/resources/src/window.cpp       | 41 +++++++++++++++-------
 .../meson-templates/resources/src/window.hpp       | 16 +++++----
 .../meson-templates/resources/src/window.ui        | 20 +++--------
 4 files changed, 44 insertions(+), 37 deletions(-)
---
diff --git a/src/plugins/meson-templates/resources/src/main.cpp 
b/src/plugins/meson-templates/resources/src/main.cpp
index f17ff4d89..58f8e5b9b 100644
--- a/src/plugins/meson-templates/resources/src/main.cpp
+++ b/src/plugins/meson-templates/resources/src/main.cpp
@@ -10,10 +10,8 @@ on_activate (Glib::RefPtr<Gtk::Application> app)
        static std::unique_ptr<Gtk::Window> window;
 
        if (!window) {
-               window = std::make_unique<{{Prefix}}Window>();
+               window = {{Prefix}}Window::create();
                window->property_application() = app;
-               window->property_default_width() = 600;
-               window->property_default_height() = 300;
                app->add_window(*window);
        }
 
diff --git a/src/plugins/meson-templates/resources/src/window.cpp 
b/src/plugins/meson-templates/resources/src/window.cpp
index 44060f0d8..8ceedee1e 100644
--- a/src/plugins/meson-templates/resources/src/window.cpp
+++ b/src/plugins/meson-templates/resources/src/window.cpp
@@ -2,17 +2,34 @@
 
 #include "{{prefix}}-window.h"
 
-{{Prefix}}Window::{{Prefix}}Window()
-       : Glib::ObjectBase("{{Prefix}}Window")
-       , Gtk::Window()
-       , headerbar(nullptr)
-       , label(nullptr)
+{{Prefix}}Window::{{Prefix}}Window(BaseObjectType* cobject,
+               const Glib::RefPtr<Gtk::Builder>& refBuilder)
+       : Gtk::ApplicationWindow(cobject)
+       , m_refBuilder(refBuilder)
+       , m_pLabel(nullptr)
 {
-       builder = Gtk::Builder::create_from_resource("{{appid_path}}/{{ui_file}}");
-       builder->get_widget("headerbar", headerbar);
-       builder->get_widget("label", label);
-       add(*label);
-       label->show();
-       set_titlebar(*headerbar);
-       headerbar->show();
+       // Just an example of getting widgets in derived ApplicationWindow constructor.
+       // You have to declare pointer in header file of needed type and initialize a
+       // member pointer to nullptr in constructor initializer list. But you have to
+       // do it only for widgets that you want to access or change from code.
+       //
+       // Here we just tilt the label by 30 degrees.
+       m_refBuilder->get_widget("label", m_pLabel);
+       m_pLabel->set_angle(30);
+}
+
+{{Prefix}}Window* {{Prefix}}Window::create()
+{
+       // Parse a resource file containing a GtkBuilder UI definition.
+       auto builder = Gtk::Builder::create_from_resource("{{appid_path}}/{{ui_file}}");
+
+       // Get ApplicationWindow that is specified in the UI file but
+       // implemented in our code. So our ApplicationWindow is derived.
+       {{Prefix}}Window* window = nullptr;
+       builder->get_widget_derived("appwindow", window);
+
+       if (!window)
+                       throw std::runtime_error("No \"appwindow\" object {{ui_file}}");
+
+       return window;
 }
diff --git a/src/plugins/meson-templates/resources/src/window.hpp 
b/src/plugins/meson-templates/resources/src/window.hpp
index e1151cb66..28207f624 100644
--- a/src/plugins/meson-templates/resources/src/window.hpp
+++ b/src/plugins/meson-templates/resources/src/window.hpp
@@ -5,15 +5,19 @@
 #include <gtkmm/builder.h>
 #include <gtkmm/headerbar.h>
 #include <gtkmm/label.h>
-#include <gtkmm/window.h>
+#include <gtkmm/applicationwindow.h>
 
-class {{Prefix}}Window : public Gtk::Window
+class {{Prefix}}Window : public Gtk::ApplicationWindow
 {
 public:
-       {{Prefix}}Window();
+       // Due to convention of using Gtk::Builder::get_widget_derived()
+       // constructor of the class should look like this. You can read
+       // more about it in the reference.
+       {{Prefix}}Window(BaseObjectType* cobject,
+                       const Glib::RefPtr<Gtk::Builder>& refBuilder);
 
+       static {{Prefix}}Window* create();
 private:
-       Gtk::HeaderBar *headerbar;
-       Gtk::Label *label;
-       Glib::RefPtr<Gtk::Builder> builder;
+       Glib::RefPtr<Gtk::Builder> m_refBuilder;
+       Gtk::Label* m_pLabel;
 };
diff --git a/src/plugins/meson-templates/resources/src/window.ui 
b/src/plugins/meson-templates/resources/src/window.ui
index 7522b7229..9443efccb 100644
--- a/src/plugins/meson-templates/resources/src/window.ui
+++ b/src/plugins/meson-templates/resources/src/window.ui
@@ -1,26 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <interface>
   <requires lib="gtk+" version="3.24"/>
-{{if language == "c++"}}
-  <object class="GtkHeaderBar" id="headerbar">
-    <property name="can_focus">False</property>
-    <property name="title">Hello, World!</property>
-    <property name="show_close_button">True</property>
-  </object>
-  <object class="GtkLabel" id="label">
-    <property name="can_focus">False</property>
-    <property name="label">Hello, World!</property>
-    <attributes>
-      <attribute name="weight" value="bold"/>
-      <attribute name="scale" value="2"/>
-    </attributes>
-  </object>
-{{else}}
   {{if language == "rust"}}
   <object class="GtkApplicationWindow" id="window">
+  {{else if language == "c++"}}
+       <object class="GtkApplicationWindow" id="appwindow">
   {{else}}
   <template class="{{PreFix}}Window" parent="GtkApplicationWindow">
-  {{end}}
     <property name="default-width">600</property>
     <property name="default-height">300</property>
     <child type="titlebar">
@@ -46,6 +32,8 @@
     </child>
   {{if language == "rust"}}
   </object>
+  {{else if language == "c++"}}
+  </object>
   {{else}}
   </template>
   {{end}}