Additional Inherited Members
- 1 property inherited from QObject
- 1 public slot inherited from QObject
- 1 signal inherited from QObject
- 7 static public members inherited from QObject
- 3 static public members inherited from QList
- 8 protected functions inherited from QObject
The QSignalSpy class enables introspection of signal emission.
QSignalSpy can connect to any signal of any object and records its emission. QSignalSpy itself is a list of QVariant lists. Each emission of the signal will append one item to the list, containing the arguments of the signal.
The following example records all signal emissions for the
clicked() signal of a QCheckBox:
QCheckBox *box = ...; QSignalSpy spy(box, SIGNAL(clicked(bool))); // do something that triggers the signal box->animateClick(); QCOMPARE(spy.count(), 1); // make sure the signal was emitted exactly one time QList<QVariant> arguments = spy.takeFirst(); // take the first signal QVERIFY(arguments.at(0).toBool() == true); // verify the first argument
spy.takeFirst() returns the arguments for the first emitted signal, as a list of QVariant objects. The
clicked() signal has a single bool argument, which is stored as the first entry in the list of arguments.
The example below catches a signal from a custom object:
QSignalSpy spy(myCustomObject, SIGNAL(mySignal(int, QString, double))); myCustomObject->doSomething(); // trigger emission of the signal QList<QVariant> arguments = spy.takeFirst(); QVERIFY(arguments.at(0).type() == QVariant::Int); QVERIFY(arguments.at(1).type() == QVariant::QString); QVERIFY(arguments.at(2).type() == QVariant::double);
qRegisterMetaType<QModelIndex>("QModelIndex"); QSignalSpy spy(&model, SIGNAL(whatever(QModelIndex)));
To retrieve the
QModelIndex, you can use qvariant_cast:
Member Function Documentation
QSignalSpy::QSignalSpy(QObject * object, const char * signal)
QSignalSpy spy(myPushButton, SIGNAL(clicked(bool)));
Returns true if the signal spy listens to a valid signal, otherwise false.
QByteArray QSignalSpy::signal() const
Returns the normalized signal the spy is currently listening to.
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