# QSignalTransition Class Reference ## [[QtCore](index.htm) module] The QSignalTransition class provides a transition based on a Qt signal. [More...](#details) Inherits [QAbstractTransition](qabstracttransition.html). ### Methods * `__init__ (self, QState?sourceState?=?None)` * `__init__ (self, QObject?sender, SIGNAL()?signal, QState?sourceState?=?None)` * `__init__ (self, signal?signal, QState?sourceState?=?None)` * `bool event (self, QEvent?e)` * `bool eventTest (self, QEvent?event)` * `onTransition (self, QEvent?event)` * `QObject senderObject (self)` * `setSenderObject (self, QObject?sender)` * `setSignal (self, QByteArray?signal)` * `QByteArray signal (self)` * * * ## Detailed Description The QSignalTransition class provides a transition based on a Qt signal. 通常，您將使用的過載[QState.addTransition](qstate.html#addTransition)（）采用一個發送器和信號作為參數，而不是創建QSignalTransition直接對象。 QSignalTransition是一部分[The State Machine Framework](index.htm)。 你可以繼承QSignalTransition和重新實現[eventTest](qsignaltransition.html#eventTest)（ ）方法使一個信號轉換條件;傳遞給事件對象[eventTest](qsignaltransition.html#eventTest)（）將一個[QStateMachine.SignalEvent](index.htm)對象。例如： ``` class CheckedTransition : public QSignalTransition { public: CheckedTransition([QCheckBox](qcheckbox.html) *check) : QSignalTransition(check, SIGNAL(stateChanged(int))) {} protected: bool eventTest([QEvent](qevent.html) *e) { if (!QSignalTransition.eventTest(e)) return false; [QStateMachine](qstatemachine.html).SignalEvent *se = static_cast<[QStateMachine](qstatemachine.html).SignalEvent*>(e); return (se->arguments().at(0).toInt() == [Qt](qt.html).Checked); } }; ... [QCheckBox](qcheckbox.html) *check = new [QCheckBox](qcheckbox.html)(); check->setTristate(true); [QState](qstate.html) *s1 = new [QState](qstate.html)(); [QState](qstate.html) *s2 = new [QState](qstate.html)(); CheckedTransition *t1 = new CheckedTransition(check); t1->setTargetState(s2); s1->addTransition(t1); ``` * * * ## Method Documentation ``` QSignalTransition.__init__ (self, QState?sourceState?=?None) ``` 該_sourceState_的說法，如果不是沒有，原因_self_通過Qt的，而不是PyQt的擁有。 構造具有給定一個新的信號轉換_sourceState_。 ``` QSignalTransition.__init__ (self, QObject?sender, SIGNAL()?signal, QState?sourceState?=?None) ``` 該_sourceState_的說法，如果不是沒有，原因_self_通過Qt的，而不是PyQt的擁有。 構造具有給定關聯的一個新的信號轉換_signal_的給定_sender_，并用給定的_sourceState_。 ``` QSignalTransition.__init__ (self, signal?signal, QState?sourceState?=?None) ``` 該_sourceState_的說法，如果不是沒有，原因_self_通過Qt的，而不是PyQt的擁有。 ``` bool QSignalTransition.event (self, QEvent?e) ``` 從重新實現[QObject.event](qobject.html#event)（ ） 。 ``` bool QSignalTransition.eventTest (self, QEvent?event) ``` 從重新實現[QAbstractTransition.eventTest](qabstracttransition.html#eventTest)（ ） 。 默認實現返回True，如果_event_是[QStateMachine.SignalEvent](index.htm)對象和事件的發送者和信號索引匹配這個過渡，否則返回False 。 ``` QSignalTransition.onTransition (self, QEvent?event) ``` 從重新實現[QAbstractTransition.onTransition](qabstracttransition.html#onTransition)（ ） 。 ``` QObject QSignalTransition.senderObject (self) ``` [ ``` QSignalTransition.setSenderObject (self, QObject?sender) ``` ``` QSignalTransition.setSignal (self, QByteArray?signal) ``` ](qobject.html) ``` QByteArray QSignalTransition.signal (self) ``` [](qbytearray.html)