将类方法传递给const char *参数

Question

In Qt QShortcut has such constructor

QShortcut(const QKeySequence& key, QWidget *parent,
          const char *member = 0, const char *ambiguousMember = 0,
          Qt::ShortcutContext context = Qt::WindowShortcut);

As far as I understand from documentation I can pass a method to the third parameter instead of using connect to signal activated. But how can I pass method there? Using

QShortcut* sh = new QShortcut(QKeySequence(Qt::Key_Alt, Qt::Key_1), this, &OnShortcut);

or

QShortcut* sh = new QShortcut(QKeySequence(Qt::Key_Alt, Qt::Key_1), this, &MyClass::OnShortcut);

gives errors

error: no matching function for call to 'QShortcut::QShortcut(QKeySequence, KeyPressProcessing* const, void (*)())'

Answer 1

You have to use SLOT(OnShortcut()) instead of &OnShortcut because the QShortcut class constructor requires const char * as the second and third arguments and not the pointer to a function. Thus, Qt has dedicated conversion macro SLOT that accepts the function signature as an argument and converts it in the form that suitable for establishing connection.