C++ (Cpp) QScrollBar::size示例

void ChatWindow::notificationClicked() {
    if (parentWidget()->isMinimized()) {
        parentWidget()->showNormal();
    }
    if (isHidden()) {
        show();
    }

    // find last mention
    int messageCount = ui->messagesVBoxLayout->count();
    for (unsigned int i = messageCount; i > 0; i--) {
        ChatMessageArea* area = (ChatMessageArea*)ui->messagesVBoxLayout->itemAt(i - 1)->widget();
        QRegularExpression usernameMention(mentionRegex.arg(AccountManager::getInstance().getAccountInfo().getUsername()));
        if (area->toPlainText().contains(usernameMention)) {
            int top = area->geometry().top();
            int height = area->geometry().height();

            QScrollBar* verticalScrollBar = ui->messagesScrollArea->verticalScrollBar();
            verticalScrollBar->setSliderPosition(top - verticalScrollBar->size().height() + height);
            return;
        }
    }
    Application::processEvents();

    scrollToBottom();
}