+ if(items.empty())
+ max_scroll = 0;
+ else
+ max_scroll = last_to_first(items.size()-1);
+
+ if(first>max_scroll)
+ first = max_scroll;
+
+ slider.set_range(0, max_scroll);
+ slider.set_value(max_scroll-first);
+}
+
+void List::slider_value_changed(double value)
+{
+ if(max_scroll>0 && !ignore_slider_change)
+ {
+ first = max_scroll-static_cast<unsigned>(value);
+ rebuild();
+ }
+}
+
+
+List::DataObserver::DataObserver(List &l):
+ list(l)
+{
+ list.data->signal_item_added.connect(sigc::mem_fun(this, &DataObserver::item_added));
+ list.data->signal_item_removed.connect(sigc::mem_fun(this, &DataObserver::item_removed));
+ list.data->signal_cleared.connect(sigc::mem_fun(this, &DataObserver::cleared));
+ list.data->signal_refresh_item.connect(sigc::mem_fun(this, &DataObserver::refresh_item));
+}
+
+void List::DataObserver::item_added(unsigned i)
+{
+ if(list.sel_index>=static_cast<int>(i))
+ ++list.sel_index;
+
+ Item *item = list.create_item(i);
+ list.items.insert(list.items.begin()+i, item);
+ list.items_changed();
+}
+
+void List::DataObserver::item_removed(unsigned i)
+{
+ bool had_selection = (list.sel_index>=0);
+ if(list.sel_index>static_cast<int>(i))
+ --list.sel_index;
+ else if(list.sel_index==static_cast<int>(i))
+ list.sel_index = -1;
+
+ delete list.items[i];
+ list.items.erase(list.items.begin()+i);
+ list.items_changed();
+
+ if(had_selection && list.sel_index<0)
+ list.signal_selection_cleared.emit();