Initial commit

App/UI/MainWindow.cs

@@ -0,0 +1,15 @@
+namespace App.UI;
+
+public class MainWindow
+{
+    public Adw.Window Window { get; }
+
+    public MainWindow()
+    {
+    var builder = Gtk.Builder.NewFromFile("UI/MainWindow.xml");
+        var window = builder.GetObject("main_window") as Adw.Window;
+        if (window == null)
+            throw new Exception("Failed to load main_window from MainWindow.ui");
+        Window = window;
+    }
+}

App/UI/MainWindow.xml

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <object class="AdwWindow" id="main_window">
+  <property name="width-request">280</property>
+  <property name="height-request">200</property>
+  <property name="default-width">800</property>
+  <property name="default-height">500</property>
+  <child>
+    <object class="AdwBreakpoint">
+      <condition>max-width: 500sp</condition>
+      <setter object="split_view" property="collapsed">True</setter>
+    </object>
+  </child>
+  <property name="content">
+    <object class="AdwNavigationSplitView" id="split_view">
+      <property name="sidebar">
+        <object class="AdwNavigationPage">
+          <property name="title" translatable="yes">Sidebar</property>
+          <property name="child">
+            <object class="GtkLabel">
+              <property name="label">I am a sidebar</property>
+            </object>
+          </property>
+        </object>
+      </property>
+      <property name="content">
+        <object class="AdwNavigationPage">
+          <property name="title" translatable="yes">Content</property>
+          <property name="child">
+            <object class="GtkLabel">
+              <property name="label">Hello world</property>
+            </object>
+          </property>
+        </object>
+      </property>
+    </object>
+  </property>
+</object>
+</interface>