内容

• 公共函数
• 详细描述

QSignalSpy 类

The QSignalSpy class enables introspection of signal emission. 更多...

头：	#include <QSignalSpy>
qmake:	QT += testlib
继承：	QObject and QList

• 所有成员列表，包括继承成员

公共函数

	QSignalSpy (const QObject * object , const char * signal )
	QSignalSpy (const QObject * object , PointerToMemberFunction signal )
bool	isValid () const
QByteArray	signal () const
bool	wait (int timeout = 5000)

• 32 公共函数继承自 QObject
• 78 公共函数继承自 QList

额外继承成员

• 1 特性继承自 QObject
• 1 公共槽继承自 QObject
• 2 信号继承自 QObject
• 11 静态公共成员继承自 QObject
• 3 static public members inherited from QList
• 9 保护函数继承自 QObject

详细描述

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::String);
QVERIFY(arguments.at(2).type() == QVariant::double);
					

注意： Non-standard data types need to be registered, using the qRegisterMetaType () function, before you can create a QSignalSpy 。例如：

qRegisterMetaType<SomeStruct>();
QSignalSpy spy(&model, SIGNAL(whatever(SomeStruct)));
					

To retrieve the instance, you can use qvariant_cast :

// get the first argument from the first received signal:
SomeStruct result = qvariant_cast<SomeStruct>(spy.at(0).at(0));
					

成员函数文档编制

QSignalSpy:: QSignalSpy (const QObject * object , const char * signal )

构造新的 QSignalSpy that listens for emissions of the signal 从 QObject object 。若 QSignalSpy is not able to listen for a valid signal (for example, because object is null or signal does not denote a valid signal of object ), an explanatory warning message will be output using qWarning () and subsequent calls to isValid() will return false.

范例：

QSignalSpy spy(myPushButton, SIGNAL(clicked(bool)));
					

QSignalSpy:: QSignalSpy (const QObject * object , PointerToMemberFunction signal )

构造新的 QSignalSpy that listens for emissions of the signal 从 QObject object 。若 QSignalSpy is not able to listen for a valid signal (for example, because object is null or signal does not denote a valid signal of object ), an explanatory warning message will be output using qWarning () and subsequent calls to isValid() will return false.

范例：

QSignalSpy spy(myPushButton, &QPushButton::clicked);
					

该函数在 Qt 5.4 引入。

bool QSignalSpy:: isValid () const

返回 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.

bool QSignalSpy:: wait ( int timeout = 5000)

Starts an event loop that runs until the given signal is received. Optionally the event loop can return earlier on a timeout (in milliseconds).

返回 true if the signal was emitted at least once in timeout milliseconds, otherwise returns false .

范例：

QVERIFY(spy.wait(1000));
					

该函数在 Qt 5.0 引入。