C++ PlatformKeyboardEvent::windowsVirtualKeyCode方法代码示例

// From HTMLSelectElement.cpp, with modifications
void PopupListBox::typeAheadFind(const PlatformKeyboardEvent& event)
{
    TimeStamp now = static_cast<TimeStamp>(currentTime() * 1000.0f);
    TimeStamp delta = now - m_lastCharTime;

    // Reset the time when user types in a character. The time gap between
    // last character and the current character is used to indicate whether
    // user typed in a string or just a character as the search prefix.
    m_lastCharTime = now;

    UChar c = event.windowsVirtualKeyCode();

    String prefix;
    int searchStartOffset = 1;
    if (delta > typeAheadTimeoutMs) {
        m_typedString = prefix = String(&c, 1);
        m_repeatingChar = c;
    } else {
        m_typedString.append(c);

        if (c == m_repeatingChar) {
            // The user is likely trying to cycle through all the items starting
            // with this character, so just search on the character.
            prefix = String(&c, 1);
        } else {
            m_repeatingChar = 0;
            prefix = m_typedString;
            searchStartOffset = 0;
        }
    }

    // Compute a case-folded copy of the prefix string before beginning the
    // search for a matching element. This code uses foldCase to work around the
    // fact that String::startWith does not fold non-ASCII characters. This code
    // can be changed to use startWith once that is fixed.
    String prefixWithCaseFolded(prefix.foldCase());
    int itemCount = numItems();
    int index = (max(0, m_selectedIndex) + searchStartOffset) % itemCount;
    for (int i = 0; i < itemCount; i++, index = (index + 1) % itemCount) {
        if (!isSelectableItem(index))
            continue;

        if (stripLeadingWhiteSpace(m_items[index]->label).foldCase().startsWith(prefixWithCaseFolded)) {
            selectIndex(index);
            return;
        }
    }
}

static inline KeyboardEvent::KeyLocationCode keyLocationCode(const PlatformKeyboardEvent& key)
{
    if (key.isKeypad())
        return KeyboardEvent::DOM_KEY_LOCATION_NUMPAD;

    switch (key.windowsVirtualKeyCode()) {
    case VK_LCONTROL:
    case VK_LSHIFT:
    case VK_LMENU:
    case VK_LWIN:
        return KeyboardEvent::DOM_KEY_LOCATION_LEFT;
    case VK_RCONTROL:
    case VK_RSHIFT:
    case VK_RMENU:
    case VK_RWIN:
        return KeyboardEvent::DOM_KEY_LOCATION_RIGHT;
    default:
        return KeyboardEvent::DOM_KEY_LOCATION_STANDARD;
    }
}

bool PopupListBox::handleKeyEvent(const PlatformKeyboardEvent& event)
{
    if (event.type() == PlatformEvent::KeyUp)
        return true;

    if (!numItems() && event.windowsVirtualKeyCode() != VKEY_ESCAPE)
        return true;

    switch (event.windowsVirtualKeyCode()) {
    case VKEY_ESCAPE:
        abandon(); // may delete this
        return true;
    case VKEY_RETURN:
        if (m_selectedIndex == -1)  {
            hidePopup();
            // Don't eat the enter if nothing is selected.
            return false;
        }
        acceptIndex(m_selectedIndex); // may delete this
        return true;
    case VKEY_UP:
    case VKEY_DOWN:
        // We have to forward only shift + up combination to focused node when
        // autofill popup. Because all characters from the cursor to the start
        // of the text area should selected when you press shift + up arrow.
        // shift + down should be the similar way to shift + up.
        if (event.modifiers() && m_popupClient->menuStyle().menuType() == PopupMenuStyle::AutofillPopup)
            m_focusedElement->dispatchKeyEvent(event);
        else if (event.windowsVirtualKeyCode() == VKEY_UP)
            selectPreviousRow();
        else
            selectNextRow();
        break;
    case VKEY_PRIOR:
        adjustSelectedIndex(-m_visibleRows);
        break;
    case VKEY_NEXT:
        adjustSelectedIndex(m_visibleRows);
        break;
    case VKEY_HOME:
        adjustSelectedIndex(-m_selectedIndex);
        break;
    case VKEY_END:
        adjustSelectedIndex(m_items.size());
        break;
    default:
        if (!event.ctrlKey() && !event.altKey() && !event.metaKey()
            && isPrintableChar(event.windowsVirtualKeyCode())
            && isCharacterTypeEvent(event))
            typeAheadFind(event);
        break;
    }

    if (m_originalIndex != m_selectedIndex) {
        // Keyboard events should update the selection immediately (but we don't
        // want to fire the onchange event until the popup is closed, to match
        // IE). We change the original index so we revert to that when the
        // popup is closed.
        if (m_settings.acceptOnAbandon)
            m_acceptedIndexOnAbandon = m_selectedIndex;

        setOriginalIndex(m_selectedIndex);
        if (m_settings.setTextOnIndexChange)
            m_popupClient->setTextFromItem(m_selectedIndex);
    }
    if (event.windowsVirtualKeyCode() == VKEY_TAB) {
        // TAB is a special case as it should select the current item if any and
        // advance focus.
        if (m_selectedIndex >= 0) {
            acceptIndex(m_selectedIndex); // May delete us.
            // Return false so the TAB key event is propagated to the page.
            return false;
        }
        // Call abandon() so we honor m_acceptedIndexOnAbandon if set.
        abandon();
        // Return false so the TAB key event is propagated to the page.
        return false;
    }

    return true;
}