examples\dialogs\extension下面的例子
moreButton = new QPushButton(tr("&More"));
moreButton->setCheckable(true); ←●
//! [0]
moreButton->setAutoDefault(false);
buttonBox = new QDialogButtonBox(Qt::Vertical);
buttonBox->addButton(findButton, QDialogButtonBox::ActionRole);
buttonBox->addButton(moreButton, QDialogButtonBox::ActionRole);
//! [1]
//! [2]
extension = new QWidget; ←●
wholeWordsCheckBox = new QCheckBox(tr("&Whole words"));
backwardCheckBox = new QCheckBox(tr("Search &backward"));
searchSelectionCheckBox = new QCheckBox(tr("Search se&lection"));
//! [2]
//! [3]
connect(moreButton, SIGNAL(toggled(bool)), extension, SLOT(setVisible(bool))); ←●