ScreenSaver: Refactor list item selection

Split out the list emptying into an EmptyScreenSaverList() method and use it in
various places where it should happen.

Call PopulateScreenSaverList() in ModulesView::AttachedToWindow() instead
of in the constructor because some of the methods depend on the view being
attached.

Don't try to select Blackness saver by name, instead if no other selection
is located select it as the default. Also, a tiny optimization, once we've found a
selection there's no reason to continue to keep looking for another one.

src/preferences/screensaver/ScreenSaverWindow.cpp

@@ -31,6 +31,7 @@
 #include <Font.h>
 #include <Layout.h>
 #include <LayoutBuilder.h>
+#include <ListItem.h>
 #include <ListView.h>
 #include <Path.h>
 #include <Roster.h>
@@ -137,7 +138,9 @@ public:
 	virtual	void				AllAttached();
 	virtual	void				MessageReceived(BMessage* message);
 
+			void				EmptyScreenSaverList();
 			void				PopulateScreenSaverList();
+
 			void				SaveState();
 
 private:
@@ -558,8 +561,6 @@ ModulesView::ModulesView(const char* name, ScreenSaverSettings& settings)
 			.End()
 		.Add(fSettingsBox)
 		.End();
-
-	PopulateScreenSaverList();
 }
 
 
@@ -573,6 +574,8 @@ void
 ModulesView::DetachedFromWindow()
 {
 	SaveState();
+	EmptyScreenSaverList();
+
 	_CloseSaver();
 }
 
@@ -580,6 +583,8 @@ ModulesView::DetachedFromWindow()
 void
 ModulesView::AttachedToWindow()
 {
+	PopulateScreenSaverList();
+
 	_OpenSaver();
 
 	fScreenSaversListView->SetTarget(this);
@@ -602,7 +607,7 @@ ModulesView::MessageReceived(BMessage* message)
 	switch (message->what) {
 		case kMsgSaverSelected:
 		{
-			int selection = fScreenSaversListView->CurrentSelection();
+			int32 selection = fScreenSaversListView->CurrentSelection();
 			if (selection < 0)
 				break;
 
@@ -689,18 +694,22 @@ ModulesView::SaveState()
 }
 
 
+void
+ModulesView::EmptyScreenSaverList()
+{
+	fScreenSaversListView->DeselectAll();
+	while (BListItem* item = fScreenSaversListView->RemoveItem((int32)0))
+		delete item;
+}
+
+
 void
 ModulesView::PopulateScreenSaverList()
 {
- 	fScreenSaversListView->DeselectAll();
-	while (ScreenSaverItem* item
-			= (ScreenSaverItem*)fScreenSaversListView->RemoveItem((int32)0)) {
-		delete item;
-	}
-
 	// Blackness is a built-in screen saver
-	fScreenSaversListView->AddItem(
-		new ScreenSaverItem(B_TRANSLATE("Blackness"), ""));
+	ScreenSaverItem* defaultItem
+		= new ScreenSaverItem(B_TRANSLATE("Blackness"), "");
+	fScreenSaversListView->AddItem(defaultItem);
 
 	// Iterate over add-on directories, and add their files to the list view
 
@@ -709,7 +718,7 @@ ModulesView::PopulateScreenSaverList()
 		B_COMMON_ADDONS_DIRECTORY,
 		B_SYSTEM_ADDONS_DIRECTORY,
 	};
-	ScreenSaverItem* selectItem = NULL;
+	ScreenSaverItem* selectedItem = NULL;
 
 	for (uint32 i = 0; i < sizeof(which) / sizeof(which[0]); i++) {
 		BPath basePath;
@@ -729,17 +738,19 @@ ModulesView::PopulateScreenSaverList()
 			ScreenSaverItem* item = new ScreenSaverItem(name, path.Path());
 			fScreenSaversListView->AddItem(item);
 
-			if (strcmp(fSettings.ModuleName(), item->Text()) != 0
-				|| (strcmp(fSettings.ModuleName(), "") != 0
-					&& strcmp(item->Text(), B_TRANSLATE("Blackness")) != 0)) {
-				selectItem = item;
-			}
+			if (selectedItem != NULL)
+				continue;
+
+			if (strcmp(fSettings.ModuleName(), item->Text()) == 0)
+				selectedItem = item;
 		}
 	}
 
 	fScreenSaversListView->SortItems(_CompareScreenSaverItems);
+	if (selectedItem == NULL)
+		selectedItem = defaultItem;
 
-	fScreenSaversListView->Select(fScreenSaversListView->IndexOf(selectItem));
+	fScreenSaversListView->Select(fScreenSaversListView->IndexOf(selectedItem));
 	fScreenSaversListView->ScrollToSelection();
 }
 
@@ -909,6 +920,7 @@ ScreenSaverWindow::MessageReceived(BMessage *message)
 			break;
 
 		case kMsgUpdateList:
+			fModulesView->EmptyScreenSaverList();
 			fModulesView->PopulateScreenSaverList();
 			break;