scrolledwindow: Add ::edge-overshot signal

This signal is emitted whenever user scrolling hits the overshoot
edge in the given direction. May be useful to add "reload" or "load
more" behaviors in apps.

https://bugzilla.gnome.org/show_bug.cgi?id=738534

1 files changed, 129 insertions, 0 deletions

diff --git a/tests/testscrolledge.c b/tests/testscrolledge.c
new file mode 100644
index 0000000000..c92402df58
--- /dev/null
+++ b/tests/testscrolledge.c
@@ -0,0 +1,129 @@
+/* testscrolledge.c
+ *
+ * Copyright (C) 2014 Matthias Clasen <mclasen@redhat.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gtk/gtk.h>
+
+static guint add_rows_id = 0;
+
+static void
+populate_list (GtkListBox *list)
+{
+  gint i;
+  gchar *text;
+  GtkWidget *row, *label;
+  gint n;
+  GList *l;
+
+  l = gtk_container_get_children (GTK_CONTAINER (list));
+  n = g_list_length (l);
+  g_list_free (l);
+
+  for (i = 1; i <= 50; i++)
+    {
+      row = gtk_list_box_row_new ();
+      text = g_strdup_printf ("List row %d", i + n);
+      label = gtk_label_new (text);
+      g_free (text);
+
+      g_object_set (label, "margin", 10, NULL);
+      gtk_widget_set_halign (label, GTK_ALIGN_START);
+      gtk_container_add (GTK_CONTAINER (row), label);
+      gtk_widget_show_all (row);
+      gtk_container_add (GTK_CONTAINER (list), row);
+    }
+}
+
+static GtkWidget *popup;
+static GtkWidget *spinner;
+
+static gboolean
+add_rows (gpointer data)
+{
+  GtkListBox *list = data;
+
+  gtk_widget_hide (popup);
+  gtk_spinner_stop (GTK_SPINNER (spinner));
+
+  populate_list (list);
+  add_rows_id = 0;
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+edge_overshot (GtkScrolledWindow *sw,
+               GtkPositionType    pos,
+               GtkListBox        *list)
+{
+  if (pos == GTK_POS_BOTTOM)
+    {
+      gtk_spinner_start (GTK_SPINNER (spinner));
+      gtk_widget_show (popup);
+
+      if (add_rows_id == 0)
+        add_rows_id = g_timeout_add (2000, add_rows, list);
+    }
+}
+
+int
+main (int argc, char *argv[])
+{
+  GtkWidget *win;
+  GtkWidget *sw;
+  GtkWidget *list;
+  GtkWidget *overlay;
+  GtkWidget *label;
+
+  gtk_init (NULL, NULL);
+
+  win = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+  gtk_window_set_default_size (GTK_WINDOW (win), 600, 400);
+
+  overlay = gtk_overlay_new ();
+  popup = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 10);
+  gtk_widget_set_halign (popup, GTK_ALIGN_CENTER);
+  gtk_widget_set_valign (popup, GTK_ALIGN_END);
+  g_object_set (popup, "margin", 40, NULL);
+  label = gtk_label_new ("Getting more rows...");
+  spinner = gtk_spinner_new ();
+  gtk_widget_show (spinner);
+  gtk_widget_show (label);
+  gtk_container_add (GTK_CONTAINER (popup), label);
+  gtk_container_add (GTK_CONTAINER (popup), spinner);
+
+  gtk_overlay_add_overlay (GTK_OVERLAY (overlay), popup);
+  gtk_widget_set_no_show_all (popup, TRUE);
+
+  sw = gtk_scrolled_window_new (NULL, NULL);
+  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw), GTK_POLICY_NEVER, GTK_POLICY_AUTOMATIC);
+  list = gtk_list_box_new ();
+  gtk_list_box_set_selection_mode (GTK_LIST_BOX (list), GTK_SELECTION_NONE);
+
+  gtk_container_add (GTK_CONTAINER (win), overlay);
+  gtk_container_add (GTK_CONTAINER (overlay), sw);
+  gtk_container_add (GTK_CONTAINER (sw), list);
+  populate_list (GTK_LIST_BOX (list));
+
+  g_signal_connect (sw, "edge-overshot", G_CALLBACK (edge_overshot), list);
+
+  gtk_widget_show_all (win);
+
+  gtk_main ();
+
+  return 0;
+}