C++ DropDownList类代码示例

	/**
	 * Find the dropdown item under the cursor.
	 * @param value [out] Selected item, if function returns \c true.
	 * @return Cursor points to a dropdown item.
	 */
	bool GetDropDownItem(int &value)
	{
		if (GetWidgetFromPos(this, _cursor.pos.x - this->left, _cursor.pos.y - this->top) < 0) return false;

		NWidgetBase *nwi = this->GetWidget<NWidgetBase>(DDM_ITEMS);
		int y     = _cursor.pos.y - this->top - nwi->pos_y - 2;
		int width = nwi->current_x - 4;
		int pos   = this->vscroll->GetPosition();

		const DropDownList *list = this->list;

		for (DropDownList::const_iterator it = list->begin(); it != list->end(); ++it) {
			/* Skip items that are scrolled up */
			if (--pos >= 0) continue;

			const DropDownListItem *item = *it;
			int item_height = item->Height(width);

			if (y < item_height) {
				if (item->masked || !item->Selectable()) return false;
				value = item->result;
				return true;
			}

			y -= item_height;
		}

		return false;
	}

	/**
	 * Helper function to construct the dropdown.
	 * @param widget the dropdown widget to create the dropdown for
	 */
	void ShowDateDropDown(int widget)
	{
		int selected;
		DropDownList *list = new DropDownList();

		switch (widget) {
			default: NOT_REACHED();

			case WID_SD_DAY:
				for (uint i = 0; i < 31; i++) {
					list->push_back(new DropDownListStringItem(STR_ORDINAL_NUMBER_1ST + i, i + 1, false));
				}
				selected = this->date.day;
				break;

			case WID_SD_MONTH:
				for (uint i = 0; i < 12; i++) {
					list->push_back(new DropDownListStringItem(STR_MONTH_JAN + i, i, false));
				}
				selected = this->date.month;
				break;

			case WID_SD_YEAR:
				for (Year i = this->min_year; i <= this->max_year; i++) {
					DropDownListParamStringItem *item = new DropDownListParamStringItem(STR_JUST_INT, i, false);
					item->SetParam(0, i);
					list->push_back(item);
				}
				selected = this->date.year;
				break;
		}

		ShowDropDownList(this, list, selected, widget);
	}

void linkInputLabels()
{
    GraphicLayer* layer = GraphicLayer::sharedLayer();
    CCArray* children = layer->getChildren();
    if(children != NULL)
    {
        for(int i = 0 ; i < children->count(); i++)
        {
            RawObject* child = (RawObject*)children->objectAtIndex(i);
            //Force actualization of content size and fontSize after everything is loaded because the nodeToWorldTransform is only right after
            if(isKindOfClass(child, InputLabel))
            {
                InputLabel* input = (InputLabel*)child;
                child->getNode()->setContentSize(child->getNode()->getContentSize());
                if(input->getOriginalInfos() != NULL)
                {
                    ((ui::EditBox*)child->getNode())->setFontSize(input->getOriginalInfos()->getFontSize());
                }
            }
            if((isKindOfClass(child, InputLabel)) && child->getEventInfos()->objectForKey("LinkTo") != NULL && isKindOfClass(child->getEventInfos()->objectForKey("LinkTo"), CCString))
            {
                InputLabel* input = (InputLabel*)child;
                if(input->getLinkTo() == NULL)
                {
                    CCString* linkTo = (CCString*)child->getEventInfos()->objectForKey("LinkTo");
                    CCArray* matchs = layer->allObjectsWithName(linkTo);
                    for(long j = 0; j < matchs->count(); j++)
                    {
                        RawObject* match = (RawObject*)matchs->objectAtIndex(j);
                        if(isKindOfClass(match, LabelTTF))
                        {
                            input->setLinkTo((LabelTTF*)match);
                            j = matchs->count();
                        }
                    }
                }
            }
            else if((isKindOfClass(child, DropDownList)) && child->getEventInfos()->objectForKey("LinkTo") != NULL && isKindOfClass(child->getEventInfos()->objectForKey("LinkTo"), CCString))
            {
                DropDownList* dropDownList = (DropDownList*)child;
                if(dropDownList->getLinkTo() == NULL)
                {
                    CCString* linkTo = (CCString*)child->getEventInfos()->objectForKey("LinkTo");
                    CCArray* matchs = layer->allObjectsWithName(linkTo);
                    for(long j = 0; j < matchs->count(); j++)
                    {
                        RawObject* match = (RawObject*)matchs->objectAtIndex(j);
                        if(isKindOfClass(match, LabelTTF))
                        {
                            dropDownList->setLinkTo((LabelTTF*)match);
                            j = matchs->count();
                        }
                    }
                }
            }
        }
    }
}

	/** Build a dropdown list of available airport classes */
	static DropDownList *BuildAirportClassDropDown()
	{
		DropDownList *list = new DropDownList();

		for (uint i = 0; i < AirportClass::GetCount(); i++) {
			list->push_back(new DropDownListStringItem(AirportClass::GetName((AirportClassID)i), i, false));
		}

		return list;
	}

	/** Build a dropdown list of available airport classes */
	static DropDownList *BuildAirportClassDropDown()
	{
		DropDownList *list = new DropDownList();

		for (uint i = 0; i < AirportClass::GetClassCount(); i++) {
			*list->Append() = new DropDownListStringItem(AirportClass::Get((AirportClassID)i)->name, i, false);
		}

		return list;
	}

/**
 * Update/redraw the group action dropdown
 * @param w   the window the dropdown belongs to
 * @param gid the currently selected group in the window
 */
static void ShowGroupActionDropdown(Window *w, GroupID gid)
{
	DropDownList *list = new DropDownList();

	list->push_back(new DropDownListStringItem(STR_VEHICLE_LIST_REPLACE_VEHICLES,    GALF_REPLACE, false));
	list->push_back(new DropDownListStringItem(STR_VEHICLE_LIST_SEND_FOR_SERVICING,  GALF_SERVICE, false));
	list->push_back(new DropDownListStringItem(STR_VEHICLE_LIST_SEND_TRAIN_TO_DEPOT, GALF_DEPOT,   false));

	if (Group::IsValidID(gid)) {
		list->push_back(new DropDownListStringItem(STR_GROUP_ADD_SHARED_VEHICLE,  GALF_ADD_SHARED, false));
		list->push_back(new DropDownListStringItem(STR_GROUP_REMOVE_ALL_VEHICLES, GALF_REMOVE_ALL, false));
	}

	ShowDropDownList(w, list, 0, GRP_WIDGET_MANAGE_VEHICLES_DROPDOWN);
}

	/**
	 * Create a dropdown menu.
	 * @param parent        Parent window.
	 * @param list          Dropdown item list.
	 * @param selected      Index of the selected item in the list.
	 * @param button        Widget of the parent window doing the dropdown.
	 * @param instant_close Close the window when the mouse button is raised.
	 * @param position      Topleft position of the dropdown menu window.
	 * @param size          Size of the dropdown menu window.
	 * @param wi_colour     Colour of the parent widget.
	 * @param scroll        Dropdown menu has a scrollbar.
	 * @param widget        Widgets of the dropdown menu window.
	 */
	DropdownWindow(Window *parent, const DropDownList *list, int selected, int button, bool instant_close, const Point &position, const Dimension &size, Colours wi_colour, bool scroll)
			: Window(&_dropdown_desc)
	{
		assert(list->Length() > 0);

		this->position = position;

		this->CreateNestedTree();

		this->vscroll = this->GetScrollbar(WID_DM_SCROLL);

		uint items_width = size.width - (scroll ? NWidgetScrollbar::GetVerticalDimension().width : 0);
		NWidgetCore *nwi = this->GetWidget<NWidgetCore>(WID_DM_ITEMS);
		nwi->SetMinimalSize(items_width, size.height + 4);
		nwi->colour = wi_colour;

		nwi = this->GetWidget<NWidgetCore>(WID_DM_SCROLL);
		nwi->colour = wi_colour;

		this->GetWidget<NWidgetStacked>(WID_DM_SHOW_SCROLL)->SetDisplayedPlane(scroll ? 0 : SZSP_NONE);

		this->FinishInitNested(0);
		CLRBITS(this->flags, WF_WHITE_BORDER);

		/* Total length of list */
		int list_height = 0;
		for (const DropDownListItem * const *it = list->Begin(); it != list->End(); ++it) {
			const DropDownListItem *item = *it;
			list_height += item->Height(items_width);
		}

		/* Capacity is the average number of items visible */
		this->vscroll->SetCapacity(size.height * (uint16)list->Length() / list_height);
		this->vscroll->SetCount((uint16)list->Length());

		this->parent_wnd_class = parent->window_class;
		this->parent_wnd_num   = parent->window_number;
		this->parent_button    = button;
		this->list             = list;
		this->selected_index   = selected;
		this->click_delay      = 0;
		this->drag_mode        = instant_close;
		this->instant_close    = instant_close;
		this->left_button_state = _left_button_down;
	}

/**
 * Show a dropdown menu window near a widget of the parent window.
 * The result code of the items is their index in the #strings list.
 * @param w             Parent window that wants the dropdown menu.
 * @param strings       Menu list, end with #INVALID_STRING_ID
 * @param selected      Index of initial selected item.
 * @param button        Button widget number of the parent window #w that wants the dropdown menu.
 * @param disabled_mask Bitmask for diabled items (items with their bit set are not copied to the dropdown list).
 * @param hidden_mask   Bitmask for hidden items (items with their bit set are displayed, but not selectable in the dropdown list).
 * @param width         Width of the dropdown menu. If \c 0, use the width of parent widget #button.
 */
void ShowDropDownMenu(Window *w, const StringID *strings, int selected, int button, uint32 disabled_mask, uint32 hidden_mask, uint width)
{
	DropDownList *list = new DropDownList();

	for (uint i = 0; strings[i] != INVALID_STRING_ID; i++) {
		if (!HasBit(hidden_mask, i)) {
			list->push_back(new DropDownListStringItem(strings[i], i, HasBit(disabled_mask, i)));
		}
	}

	/* No entries in the list? */
	if (list->size() == 0) {
		DeleteDropDownList(list);
		return;
	}

	ShowDropDownList(w, list, selected, button, width);
}

void DropDownList::hide(bool event, bool allow_veto) {
    // hide?
    bool keep_open = event && allow_veto && stayOpen(selected_item);
    if (keep_open) {
        close_on_mouse_out = true;
    } else {
        // hide root
        DropDownList* root = this;
        while (root->parent_menu) {
            root = root->parent_menu;
        }
        root->realHide();
    }
    // send event
    if (event && selected_item != NO_SELECTION && itemEnabled(selected_item)) {
        select(selected_item);
        if (IsShown()) Refresh(false);
    }
}

void ModalListPicker::CorrectListSize() {
    // reset size of displayed drop list based on number of shown rows set.
    // assumes that all rows have the same height.
    // adds some magic padding for now to prevent the scroll bars showing up.

    if (!m_relative_to_wnd)
        return;

    if (LB()->Visible())
        return;

    LB()->MoveTo(Pt(m_relative_to_wnd->Left(), m_relative_to_wnd->Bottom()));

    Pt drop_down_size(m_relative_to_wnd->DroppedRowWidth(), m_relative_to_wnd->ClientHeight());

    if (LB()->Empty()) {
        LB()->Resize(drop_down_size);
    } else {
        LB()->Show();

        // The purpose of this code is to produce a drop down list that
        // will be exactly m_num_shown_rows high and make sure that the
        // selected row is prerendered in the same way when the drop down
        // list is open or closed.

        // The list needs to be resized twice.  The first resize with an
        // estimated row height will add any list box chrome, like scroll
        // bars to the list and may change the height of the row.  The
        // second resize uses the corrected row height to finalize the drop
        // down list size.

        // Note:  Placing a tighter constraint on valid DropDownList rows
        // of always returning the same fixed height regardless of status
        // (width, prerender etc.) would mean this code could be reduced to
        // check height and resize list just once.

        drop_down_size = DetermineListHeight(drop_down_size);
        DetermineListHeight(drop_down_size);

        LB()->Hide();
    }
}

	virtual void OnClick(Point pt, int widget, int click_count)
	{
		switch (widget) {
			case SNGRFS_PRESET_LIST: {
				DropDownList *list = new DropDownList();

				/* Add 'None' option for clearing list */
				list->push_back(new DropDownListStringItem(STR_NONE, -1, false));

				for (uint i = 0; i < _grf_preset_list.Length(); i++) {
					if (_grf_preset_list[i] != NULL) {
						list->push_back(new DropDownListPresetItem(i));
					}
				}

				ShowDropDownList(this, list, this->preset, SNGRFS_PRESET_LIST);
				break;
			}

			case SNGRFS_PRESET_SAVE:
				this->query_widget = widget;
				ShowQueryString(STR_EMPTY, STR_NEWGRF_SETTINGS_PRESET_SAVE_QUERY, 32, 100, this, CS_ALPHANUMERAL, QSF_NONE);
				break;

			case SNGRFS_PRESET_DELETE:
				if (this->preset == -1) return;

				DeleteGRFPresetFromConfig(_grf_preset_list[this->preset]);
				GetGRFPresetList(&_grf_preset_list);
				this->preset = -1;
				this->InvalidateData();
				break;

			case SNGRFS_ADD: // Add GRF
				DeleteWindowByClass(WC_SAVELOAD);
				new NewGRFAddWindow(&_newgrf_add_dlg_desc, this, &this->list);
				break;

			case SNGRFS_REMOVE: { // Remove GRF
				GRFConfig **pc, *c, *newsel;

				/* Choose the next GRF file to be the selected file */
				newsel = this->sel->next;

				for (pc = &this->list; (c = *pc) != NULL; pc = &c->next) {
					/* If the new selection is empty (i.e. we're deleting the last item
					 * in the list, pick the file just before the selected file */
					if (newsel == NULL && c->next == this->sel) newsel = c;

					if (c == this->sel) {
						*pc = c->next;
						free(c);
						break;
					}
				}

				this->sel = newsel;
				this->preset = -1;
				this->InvalidateData(3);
				this->DeleteChildWindows(WC_QUERY_STRING); // Remove the parameter query window
				break;
			}

			case SNGRFS_MOVE_UP: { // Move GRF up
				GRFConfig **pc, *c;
				if (this->sel == NULL) break;

				int pos = 0;
				for (pc = &this->list; (c = *pc) != NULL; pc = &c->next, pos++) {
					if (c->next == this->sel) {
						c->next = this->sel->next;
						this->sel->next = c;
						*pc = this->sel;
						break;
					}
				}
				this->vscroll.ScrollTowards(pos);
				this->preset = -1;
				this->InvalidateData();
				break;
			}

			case SNGRFS_MOVE_DOWN: { // Move GRF down
				GRFConfig **pc, *c;
				if (this->sel == NULL) break;

				int pos = 1; // Start at 1 as we swap the selected newgrf with the next one
				for (pc = &this->list; (c = *pc) != NULL; pc = &c->next, pos++) {
					if (c == this->sel) {
						*pc = c->next;
						c->next = c->next->next;
						(*pc)->next = c;
						break;
					}
				}
				this->vscroll.ScrollTowards(pos);
				this->preset = -1;
				this->InvalidateData();
				break;
			}
//.........这里部分代码省略.........

Pt ModalListPicker::DetermineListHeight(const Pt& _drop_down_size) {
    auto drop_down_size = _drop_down_size;

    // Determine the expected height
    auto border_thick = 2 * GG::Y(ListBox::BORDER_THICK);
    auto num_rows = std::min<int>(m_num_shown_rows, LB()->NumRows());
    auto row_height = (*LB()->FirstRowShown())->Height();
    auto expected_height = num_rows * row_height + border_thick;

    // Shrink the height if too near app edge.
    auto dist_to_app_edge = GUI::GetGUI()->AppHeight() - m_relative_to_wnd->Bottom();
    if (expected_height > dist_to_app_edge && row_height > 0) {
        auto reduced_num_rows = std::max(GG::Y(1), (dist_to_app_edge - border_thick) / row_height);
        expected_height = reduced_num_rows * row_height + border_thick;
    }

    drop_down_size.y = expected_height;

    LB()->Resize(drop_down_size);
    if (!LB()->Selections().empty())
        LB()->BringRowIntoView(*(LB()->Selections().begin()));
    GUI::GetGUI()->PreRenderWindow(LB());

    return drop_down_size;
}

void ModalListPicker::MouseWheel(const Pt& pt, int move, Flags<ModKey> mod_keys)
{
    bool in_anchor_or_dropped_list = (LB()->InWindow(pt) || (m_relative_to_wnd && m_relative_to_wnd->InWindow(pt)));
    if (!in_anchor_or_dropped_list)
        return;

    auto corrected_move = (LB()->InWindow(pt)? move : -move);
    SignalChanged(Select(MouseWheelCommon(pt, corrected_move, mod_keys)));
}

void ModalListPicker::CompleteConstruction()
{
    m_lb_wnd->SelRowsChangedSignal.connect(
        boost::bind(&ModalListPicker::LBSelChangedSlot, this, _1));
    m_lb_wnd->LeftClickedRowSignal.connect(
        boost::bind(&ModalListPicker::LBLeftClickSlot, this, _1, _2, _3));
    GUI::GetGUI()->WindowResizedSignal.connect(
        boost::bind(&ModalListPicker::WindowResizedSlot, this, _1, _2));
    AttachChild(m_lb_wnd);
    m_lb_wnd->InstallEventFilter(shared_from_this());

    if (INSTRUMENT_ALL_SIGNALS)
        SelChangedSignal.connect(ModalListPickerSelChangedEcho(*this));

    if (m_relative_to_wnd)
        m_lb_wnd->MoveTo(Pt(m_relative_to_wnd->Left(), m_relative_to_wnd->Bottom()));

    m_lb_wnd->Hide();
}