QWhatsThisPrivate Class Reference

Inheritance diagram for QWhatsThisPrivate:

Public Functions
bool	eventFilter (QObject *, QEvent *)
	Filters events if this object has been installed as an event filter for the watched object. More...
	QWhatsThisPrivate ()
	~QWhatsThisPrivate ()
Public Functions inherited from QObject
bool	blockSignals (bool b)
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More...
const QObjectList &	children () const
	Returns a list of child objects. More...
bool	connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char *signal=0, const QObject *receiver=0, const char *member=0)
bool	disconnect (const QObject *receiver, const char *member=0)
void	dumpObjectInfo ()
	Dumps information about signal connections, etc. More...
void	dumpObjectTree ()
	Dumps a tree of children to the debug output. More...
QList< QByteArray >	dynamicPropertyNames () const
	Returns the names of all properties that were dynamically added to the object using setProperty(). More...
virtual bool	event (QEvent *)
	This virtual function receives events to an object and should return true if the event e was recognized and processed. More...
template<typename T >
T	findChild (const QString &aName=QString()) const
	Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More...
template<typename T >
QList< T >	findChildren (const QString &aName=QString()) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. More...
template<typename T >
QList< T >	findChildren (const QRegExp &re) const
bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. More...
void	installEventFilter (QObject *)
	Installs an event filter filterObj on this object. More...
bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false. More...
void	killTimer (int id)
	Kills the timer with timer identifier, id. More...
virtual const QMetaObject *	metaObject () const
	Returns a pointer to the meta-object of this object. More...
void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children. More...
QString	objectName () const
QObject *	parent () const
	Returns a pointer to the parent object. More...
QVariant	property (const char *name) const
	Returns the value of the object's name property. More...
Q_INVOKABLE	QObject (QObject *parent=0)
	Constructs an object with parent object parent. More...
void	removeEventFilter (QObject *)
	Removes an event filter object obj from this object. More...
void	setObjectName (const QString &name)
void	setParent (QObject *)
	Makes the object a child of parent. More...
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value. More...
void	setUserData (uint id, QObjectUserData *data)
bool	signalsBlocked () const
	Returns true if signals are blocked; otherwise returns false. More...
int	startTimer (int interval)
	Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More...
QThread *	thread () const
	Returns the thread in which the object lives. More...
QObjectUserData *	userData (uint id) const
virtual	~QObject ()
	Destroys the object, deleting all its child objects. More...

Static Public Functions
static void	notifyToplevels (QEvent *e)
static void	say (QWidget *, const QString &, int x=0, int y=0)
Static Public Functions inherited from QObject
static bool	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
	Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More...
static bool	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
static bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
	Disconnects signal in object sender from method in object receiver. More...
static bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
static uint	registerUserData ()
static QString	tr (const char *sourceText, const char *comment=0, int n=-1)
static QString	trUtf8 (const char *sourceText, const char *comment=0, int n=-1)

Public Variables
QPointer< QAction >	action
bool	leaveOnMouseRelease

Static Public Variables
static QWhatsThisPrivate *	instance = 0
Static Public Variables inherited from QObject
static const QMetaObject	staticMetaObject
	This variable stores the meta-object for the class. More...

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()
	Schedules this object for deletion. More...
Signals inherited from QObject
void	destroyed (QObject *=0)
	This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More...
Protected Functions inherited from QObject
virtual void	childEvent (QChildEvent *)
	This event handler can be reimplemented in a subclass to receive child events. More...
virtual void	connectNotify (const char *signal)
	This virtual function is called when something has been connected to signal in this object. More...
virtual void	customEvent (QEvent *)
	This event handler can be reimplemented in a subclass to receive custom events. More...
virtual void	disconnectNotify (const char *signal)
	This virtual function is called when something has been disconnected from signal in this object. More...
	QObject (QObjectPrivate &dd, QObject *parent=0)
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal. More...
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns 0. More...
int	senderSignalIndex () const
virtual void	timerEvent (QTimerEvent *)
	This event handler can be reimplemented in a subclass to receive timer events for the object. More...
Protected Variables inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Static Protected Variables inherited from QObject
static const QMetaObject	staticQtMetaObject
Related Functions inherited from QObject
T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QRegExp &regExp)()
T *	qobject_cast (QObject *object)
	QObjectList
void *	qt_find_obj_child (QObject *parent, const char *type, const QString &name)
	Returns a pointer to the object named name that inherits type and with a given parent. More...

Detailed Description

Definition at line 388 of file qwhatsthis.cpp.

Constructors and Destructors

QWhatsThisPrivate()

QWhatsThisPrivate::QWhatsThisPrivate

(

)

Definition at line 415 of file qwhatsthis.cpp.

    : leaveOnMouseRelease(false)
{
    instance = this;
    qApp->installEventFilter(this);

    QPoint pos = QCursor::pos();
    if (QWidget *w = QApplication::widgetAt(pos)) {
        QHelpEvent e(QEvent::QueryWhatsThis, w->mapFromGlobal(pos), pos);
        bool sentEvent = QApplication::sendEvent(w, &e);
#ifdef QT_NO_CURSOR
        Q_UNUSED(sentEvent);
#else
        QApplication::setOverrideCursor((!sentEvent || !e.isAccepted())?
                                        Qt::ForbiddenCursor:Qt::WhatsThisCursor);
    } else {
        QApplication::setOverrideCursor(Qt::WhatsThisCursor);
#endif
    }
#ifndef QT_NO_ACCESSIBILITY
    QAccessible::updateAccessibility(this, 0, QAccessible::ContextHelpStart);
#endif
}

~QWhatsThisPrivate()

QWhatsThisPrivate::~QWhatsThisPrivate

(

)

Definition at line 439 of file qwhatsthis.cpp.

{
    if (action)
        action->setChecked(false);
#ifdef QT3_SUPPORT
    if (button)
        button->setChecked(false);
#endif
#ifndef QT_NO_CURSOR
    QApplication::restoreOverrideCursor();
#endif
#ifndef QT_NO_ACCESSIBILITY
    QAccessible::updateAccessibility(this, 0, QAccessible::ContextHelpEnd);
#endif
    instance = 0;
}

Functions

eventFilter()

bool QWhatsThisPrivate::eventFilter ( QObject *  , QEvent *    )

virtual

Filters events if this object has been installed as an event filter for the watched object.

In your reimplementation of this function, if you want to filter the event out, i.e. stop it being handled further, return true; otherwise return false.

Example:

class MainWindow : public QMainWindow
{
public:
    MainWindow();

protected:
    bool eventFilter(QObject *obj, QEvent *ev);

private:
    QTextEdit *textEdit;
};

MainWindow::MainWindow()
{
    textEdit = new QTextEdit;
    setCentralWidget(textEdit);

    textEdit->installEventFilter(this);
}

bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
    if (obj == textEdit) {
        if (event->type() == QEvent::KeyPress) {
            QKeyEvent *keyEvent = static_cast<QKeyEvent*>(event);
            qDebug() << "Ate key press" << keyEvent->key();
            return true;
        } else {
            return false;
        }
    } else {
        // pass the event on to the parent class
        return QMainWindow::eventFilter(obj, event);
    }
}

Notice in the example above that unhandled events are passed to the base class's eventFilter() function, since the base class might have reimplemented eventFilter() for its own internal purposes.

Warning

If you delete the receiver object in this function, be sure to return true. Otherwise, Qt will forward the event to the deleted object and the program might crash.

See also

installEventFilter()

Reimplemented from QObject.

Definition at line 456 of file qwhatsthis.cpp.

{
    if (!o->isWidgetType())
        return false;
    QWidget * w = static_cast<QWidget *>(o);
    bool customWhatsThis = w->testAttribute(Qt::WA_CustomWhatsThis);
    switch (e->type()) {
    case QEvent::MouseButtonPress:
    {
        QMouseEvent *me = static_cast<QMouseEvent*>(e);
        if (me->button() == Qt::RightButton || customWhatsThis)
            return false;
        QHelpEvent e(QEvent::WhatsThis, me->pos(), me->globalPos());
        if (!QApplication::sendEvent(w, &e) || !e.isAccepted())
            leaveOnMouseRelease = true;

    } break;

    case QEvent::MouseMove:
    {
        QMouseEvent *me = static_cast<QMouseEvent*>(e);
        QHelpEvent e(QEvent::QueryWhatsThis, me->pos(), me->globalPos());
        bool sentEvent = QApplication::sendEvent(w, &e);
#ifdef QT_NO_CURSOR
        Q_UNUSED(sentEvent);
#else
        QApplication::changeOverrideCursor((!sentEvent || !e.isAccepted())?
                                           Qt::ForbiddenCursor:Qt::WhatsThisCursor);
#endif
    }
    // fall through
    case QEvent::MouseButtonRelease:
    case QEvent::MouseButtonDblClick:
        if (leaveOnMouseRelease && e->type() == QEvent::MouseButtonRelease)
            QWhatsThis::leaveWhatsThisMode();
        if (static_cast<QMouseEvent*>(e)->button() == Qt::RightButton || customWhatsThis)
            return false; // ignore RMB release
        break;
    case QEvent::KeyPress:
    {
        QKeyEvent* kev = (QKeyEvent*)e;

        if (kev->key() == Qt::Key_Escape) {
            QWhatsThis::leaveWhatsThisMode();
            return true;
        } else if (customWhatsThis) {
            return false;
        } else if (kev->key() == Qt::Key_Menu ||
                    (kev->key() == Qt::Key_F10 &&
                      kev->modifiers() == Qt::ShiftModifier)) {
            // we don't react to these keys, they are used for context menus
            return false;
        } else if (kev->key() != Qt::Key_Shift && kev->key() != Qt::Key_Alt // not a modifier key
                   && kev->key() != Qt::Key_Control && kev->key() != Qt::Key_Meta) {
            QWhatsThis::leaveWhatsThisMode();
        }
    } break;
    default:
        return false;
    }
    return true;
}

notifyToplevels()

void QWhatsThisPrivate::notifyToplevels ( QEvent *  e )

static

Definition at line 404 of file qwhatsthis.cpp.

Referenced by QWhatsThis::leaveWhatsThisMode().

{
    QWidgetList toplevels = QApplication::topLevelWidgets();
    for (int i = 0; i < toplevels.count(); ++i) {
        register QWidget *w = toplevels.at(i);
        QApplication::sendEvent(w, e);
    }
}

say()

void QWhatsThisPrivate::say ( QWidget *  widget, const QString &  text, int  x = 0, int  y = 0  )

static

Definition at line 669 of file qwhatsthis.cpp.

Referenced by QWhatsThis::showText().

{
    if (text.size() == 0)
        return;
    // make a fresh widget, and set it up
    QWhatsThat *whatsThat = new QWhatsThat(
        text,
#if defined(Q_WS_X11) && !defined(QT_NO_CURSOR)
        QApplication::desktop()->screen(widget ? widget->x11Info().screen() : QCursor::x11Screen()),
#else
        0,
#endif
        widget
       );


    // okay, now to find a suitable location

    int scr = (widget ?
                QApplication::desktop()->screenNumber(widget) :
#if defined(Q_WS_X11) && !defined(QT_NO_CURSOR)
                QCursor::x11Screen()
#else
                QApplication::desktop()->screenNumber(QPoint(x,y))
#endif // Q_WS_X11
               );
    QRect screen = QApplication::desktop()->screenGeometry(scr);

    int w = whatsThat->width();
    int h = whatsThat->height();
    int sx = screen.x();
    int sy = screen.y();

    // first try locating the widget immediately above/below,
    // with nice alignment if possible.
    QPoint pos;
    if (widget)
        pos = widget->mapToGlobal(QPoint(0,0));

    if (widget && w > widget->width() + 16)
        x = pos.x() + widget->width()/2 - w/2;
    else
        x = x - w/2;

        // squeeze it in if that would result in part of what's this
        // being only partially visible
    if (x + w  + shadowWidth > sx+screen.width())
        x = (widget? (qMin(screen.width(),
                           pos.x() + widget->width())
                     ) : screen.width())
            - w;

    if (x < sx)
        x = sx;

    if (widget && h > widget->height() + 16) {
        y = pos.y() + widget->height() + 2; // below, two pixels spacing
        // what's this is above or below, wherever there's most space
        if (y + h + 10 > sy+screen.height())
            y = pos.y() + 2 - shadowWidth - h; // above, overlap
    }
    y = y + 2;

        // squeeze it in if that would result in part of what's this
        // being only partially visible
    if (y + h + shadowWidth > sy+screen.height())
        y = (widget ? (qMin(screen.height(),
                             pos.y() + widget->height())
                       ) : screen.height())
            - h;
    if (y < sy)
        y = sy;

    whatsThat->move(x, y);
    whatsThat->show();
    whatsThat->grabKeyboard();
}

Properties

action

QPointer<QAction> QWhatsThisPrivate::action

Definition at line 395 of file qwhatsthis.cpp.

Referenced by QWhatsThisAction::actionTriggered(), and ~QWhatsThisPrivate().

instance

QWhatsThisPrivate * QWhatsThisPrivate::instance = 0

static

Definition at line 393 of file qwhatsthis.cpp.

Referenced by QWhatsThis::leaveWhatsThisMode(), notifyToplevels(), QWhatsThisPrivate(), and ~QWhatsThisPrivate().

leaveOnMouseRelease

bool QWhatsThisPrivate::leaveOnMouseRelease

Definition at line 401 of file qwhatsthis.cpp.

Referenced by eventFilter().

---

The documentation for this class was generated from the following file:

• /src/gui/kernel/qwhatsthis.cpp