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Don't automatically scroll listbox when selecting an item in the middle
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kahrl committed Aug 15, 2013
1 parent d833703 commit 5e312dc40ddcd8d1e2846c3c2cf5030a6405a056
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Showing 2 changed files with 51 additions and 2 deletions.
@@ -184,6 +184,38 @@ bool GUIFormSpecMenu::checkListboxClick(std::wstring wlistboxname,
return false;
}

gui::IGUIScrollBar* GUIFormSpecMenu::getListboxScrollbar(
gui::IGUIListBox *listbox)
{
// WARNING: BLACK IRRLICHT MAGIC
// Ordinarily, due to how formspecs work (recreating the entire GUI
// when something changes), when you select an item in a textlist
// with more items than fit in the visible area, the newly selected
// item is scrolled to the bottom of the visible area. This is
// annoying and breaks GUI designs that use double clicks.

// This function helps fixing this problem by giving direct access
// to a listbox's scrollbar. This works because CGUIListBox doesn't
// cache the scrollbar position anywhere.

// If this stops working in a future irrlicht version, consider
// maintaining a local copy of irr::gui::CGUIListBox, possibly also
// fixing the other reasons why black irrlicht magic is needed.

core::list<gui::IGUIElement*> children = listbox->getChildren();
for(core::list<gui::IGUIElement*>::Iterator it = children.begin();
it != children.end(); ++it) {
gui::IGUIElement* child = *it;
if (child && child->getType() == gui::EGUIET_SCROLL_BAR) {
return static_cast<gui::IGUIScrollBar*>(child);
}
}

verbosestream<<"getListboxScrollbar: WARNING: "
<<"listbox has no scrollbar"<<std::endl;
return NULL;
}

std::vector<std::string> split(const std::string &s, char delim) {
std::vector<std::string> tokens;

@@ -616,6 +648,13 @@ void GUIFormSpecMenu::parseTextList(parserData* data,std::string element) {
e->setSelected(data->listbox_selections[fname_w]);
}

if (data->listbox_scroll.find(fname_w) != data->listbox_scroll.end()) {
gui::IGUIScrollBar *scrollbar = getListboxScrollbar(e);
if (scrollbar) {
scrollbar->setPos(data->listbox_scroll[fname_w]);
}
}

if (str_initial_selection != "")
e->setSelected(stoi(str_initial_selection.c_str())-1);

@@ -1417,11 +1456,18 @@ void GUIFormSpecMenu::regenerateGui(v2u32 screensize)

//preserve listboxes
for (unsigned int i = 0; i < m_listboxes.size(); i++) {
int selection = m_listboxes[i].second->getSelected();
std::wstring listboxname = m_listboxes[i].first.fname;
gui::IGUIListBox *listbox = m_listboxes[i].second;

int selection = listbox->getSelected();
if (selection != -1) {
std::wstring listboxname = m_listboxes[i].first.fname;
mydata.listbox_selections[listboxname] = selection;
}

gui::IGUIScrollBar *scrollbar = getListboxScrollbar(listbox);
if (scrollbar) {
mydata.listbox_scroll[listboxname] = scrollbar->getPos();
}
}

// Remove children
@@ -294,6 +294,7 @@ class GUIFormSpecMenu : public GUIModalMenu
int bp_set;
v2u32 screensize;
std::map<std::wstring,int> listbox_selections;
std::map<std::wstring,int> listbox_scroll;
} parserData;

typedef struct {
@@ -311,6 +312,8 @@ class GUIFormSpecMenu : public GUIModalMenu
// (Using some black Irrlicht magic)
bool checkListboxClick(std::wstring wlistboxname, int eventtype);

gui::IGUIScrollBar* getListboxScrollbar(gui::IGUIListBox *listbox);

void parseElement(parserData* data,std::string element);

void parseSize(parserData* data,std::string element);

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