Add GtkCustomFilter constructor and filtered list view example

examples/filteredlistview.jl

@@ -0,0 +1,45 @@
+using Gtk4, Gtk4.GLib
+
+win = GtkWindow("Listview demo with filter")
+box = GtkBox(:v)
+entry = GtkSearchEntry()
+sw = GtkScrolledWindow()
+push!(box, entry)
+push!(box, sw)
+push!(win, box)
+
+modelValues = string.(names(Gtk4))
+model = GtkStringList(modelValues)
+factory = GtkSignalListItemFactory()
+
+function setup_cb(f, li)
+    set_child(li,GtkLabel(""))
+end
+
+function bind_cb(f, li)
+    text = li[].string
+    label = get_child(li)
+    label.label = text
+end
+
+function match(list_item, user_data)
+  itemLeaf = Gtk4.GLib.find_leaf_type(list_item)
+  item = convert(itemLeaf, list_item)
+  result = startswith(item.string, entry.text)
+  return result ? Cint(1) : Cint(0)
+end
+
+filter = GtkCustomFilter((li, ud) -> match(li, ud))
+filteredModel = GtkFilterListModel(GLib.GListModel(model), filter)
+
+list = GtkListView(GtkSelectionModel(GtkSingleSelection(GLib.GListModel(filteredModel))), factory)
+list.vexpand = true
+
+signal_connect(setup_cb, factory, "setup")
+signal_connect(bind_cb, factory, "bind")
+
+signal_connect(entry, :search_changed) do w
+  @idle_add Gtk4.G_.changed(filter, Gtk4.FilterChange_DIFFERENT) 
+end
+
+sw[] = list

src/lists.jl

@@ -73,3 +73,11 @@ function GtkTreeListModel(root::GListModel, passthrough, autoexpand, create_func
     ret = ccall(("gtk_tree_list_model_new", libgtk4), Ptr{GObject}, (Ptr{GObject}, Cint, Cint, Ptr{Nothing}, Ptr{Nothing}, Ptr{Nothing}), root, passthrough, autoexpand, create_cfunc, C_NULL, C_NULL)
     convert(GtkTreeListModel, ret, true)
 end
+
+## GtkCustomFilter
+
+function GtkCustomFilter(match::Function)
+    create_cfunc = @cfunction($match, Cint, (Ptr{GObject}, Ptr{Nothing}))
+    ret = ccall(("gtk_custom_filter_new", libgtk4), Ptr{GObject}, (Ptr{Nothing}, Ptr{Nothing}, Ptr{Nothing}), create_cfunc, C_NULL, C_NULL)
+    convert(GtkCustomFilter, ret, true)
+end