search: Port demo to Vala

demos/Search/main.vala

@@ -0,0 +1,73 @@
+#! /usr/bin/env -S vala workbench.vala --pkg libadwaita-1
+
+private int results_count = 0;
+private Gtk.ListBox listbox;
+private Gtk.SearchEntry search_entry;
+
+public void main () {
+  var button = (Gtk.ToggleButton) workbench.builder.get_object ("button_search");
+  var search_bar = (Gtk.SearchBar) workbench.builder.get_object ("searchbar");
+  var stack = (Gtk.Stack) workbench.builder.get_object ("stack");
+  var main_page = (Adw.StatusPage) workbench.builder.get_object ("main_page");
+  var search_page = (Gtk.ScrolledWindow) workbench.builder.get_object ("search_page");
+  var status_page = (Adw.StatusPage) workbench.builder.get_object ("status_page");
+  search_entry = (Gtk.SearchEntry) workbench.builder.get_object ("searchentry");
+  listbox = (Gtk.ListBox) workbench.builder.get_object ("listbox");
+
+  button.clicked.connect (() => {
+    search_bar.search_mode_enabled = !search_bar.search_mode_enabled;
+  });
+
+  search_bar.notify["search-mode-enabled"].connect (() => {
+    if (search_bar.search_mode_enabled) {
+      stack.visible_child = search_page;
+    } else {
+      stack.visible_child = main_page;
+    }
+  });
+
+  string[] fruits = {
+    "Apple 🍎️",
+    "Orange 🍊️",
+    "Pear 🍐️",
+    "Watermelon 🍉️",
+    "Melon 🍈️",
+    "Pineapple 🍍️",
+    "Grape 🍇️",
+    "Kiwi 🥝️",
+    "Banana 🍌️",
+    "Peach 🍑️",
+    "Cherry 🍒️",
+    "Strawberry 🍓️",
+    "Blueberry 🫐️",
+    "Mango 🥭️",
+    "Bell Pepper 🫑️",
+  };
+
+  foreach (string fruit in fruits) {
+    var row = new Adw.ActionRow () {
+      title = fruit
+    };
+    listbox.append (row);
+  }
+  listbox.set_filter_func (filter);
+
+  search_entry.search_changed.connect (() => {
+    results_count = -1;
+    listbox.invalidate_filter ();
+    if (results_count < 0) {
+      stack.visible_child = status_page;
+    } else if (search_bar.search_mode_enabled){
+      stack.visible_child = search_page;
+    }
+  });
+}
+
+private bool filter (Gtk.ListBoxRow list_row) {
+  var row = (Adw.ActionRow) list_row;
+  bool match = search_entry.text.up () in row.title.up ();
+  if (match) {
+    results_count++;
+  }
+  return match;
+}