内容

• 公共类型
• 特性
• 公共函数
• 信号
• 重实现保护函数
• 详细描述

QHistoryState 类

The QHistoryState class provides a means of returning to a previously active substate. 更多...

头：	#include <QHistoryState>
qmake:	QT += core
Since:	Qt 4.6
继承：	QAbstractState

• 所有成员列表，包括继承成员

公共类型

enum	HistoryType { ShallowHistory, DeepHistory }

特性

• defaultState : QAbstractState *
• defaultTransition : QAbstractTransition *
• historyType : HistoryType

• 1 特性继承自 QAbstractState
• 1 特性继承自 QObject

公共函数

	QHistoryState (QState * parent = Q_NULLPTR)
	QHistoryState (HistoryType type , QState * parent = Q_NULLPTR)
	~QHistoryState ()
QAbstractState *	defaultState () const
QAbstractTransition *	defaultTransition () const
HistoryType	historyType () const
void	setDefaultState (QAbstractState * state )
void	setDefaultTransition (QAbstractTransition * transition )
void	setHistoryType (HistoryType type )

• 3 公共函数继承自 QAbstractState
• 32 公共函数继承自 QObject

信号

void	defaultStateChanged ()
void	defaultTransitionChanged ()
void	historyTypeChanged ()

• 3 信号继承自 QAbstractState
• 2 信号继承自 QObject

重实现保护函数

virtual bool	event (QEvent * e )
virtual void	onEntry (QEvent * event )
virtual void	onExit (QEvent * event )

• 3 保护函数继承自 QAbstractState
• 9 保护函数继承自 QObject

额外继承成员

• 1 公共槽继承自 QObject
• 11 静态公共成员继承自 QObject
• 3 保护函数继承自 QAbstractState
• 9 保护函数继承自 QObject

详细描述

The QHistoryState class provides a means of returning to a previously active substate.

A history state is a pseudo-state that represents the child state that the parent state was in the last time the parent state was exited. A transition with a history state as its target is in fact a transition to one or more other child states of the parent state. QHistoryState 属于 状态机框架 .

使用 setDefaultState () function to set the state that should be entered if the parent state has never been entered. Example:

QStateMachine machine;
QState *s1 = new QState();
QState *s11 = new QState(s1);
QState *s12 = new QState(s1);
QHistoryState *s1h = new QHistoryState(s1);
s1h->setDefaultState(s11);
machine.addState(s1);
QState *s2 = new QState();
machine.addState(s2);
QPushButton *button = new QPushButton();
// Clicking the button will cause the state machine to enter the child state
// that s1 was in the last time s1 was exited, or the history state's default
// state if s1 has never been entered.
s1->addTransition(button, SIGNAL(clicked()), s1h);
					

If more than one default state has to be entered, or if the transition to the default state(s) has to be acted upon, the defaultTransition should be set instead. Note that the eventTest() method of that transition will never be called: the selection and execution of the transition is done automatically when entering the history state.

By default a history state is shallow, meaning that it won't remember nested states. This can be configured through the historyType 特性。

成员类型文档编制

enum QHistoryState:: HistoryType

This enum specifies the type of history that a QHistoryState records.

常量	值	描述
QHistoryState::ShallowHistory	0	Only the immediate child states of the parent state are recorded. In this case a transition with the history state as its target will end up in the immediate child state that the parent was in the last time it was exited. This is the default.
QHistoryState::DeepHistory	1	Nested states are recorded. In this case a transition with the history state as its target will end up in the most deeply nested descendant state the parent was in the last time it was exited.

特性文档编制

defaultState : QAbstractState *

This property holds the default state of this history state

访问函数：

QAbstractState *	defaultState () const
void	setDefaultState (QAbstractState * state )

通知程序信号：

void

defaultStateChanged ()

[见下文注意事项]

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

defaultTransition : QAbstractTransition *

This property holds the default transition of this history state

访问函数：

QAbstractTransition *	defaultTransition () const
void	setDefaultTransition (QAbstractTransition * transition )

通知程序信号：

void

defaultTransitionChanged ()

[见下文注意事项]

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

historyType : HistoryType

This property holds the type of history that this history state records

此特性的默认值为 QHistoryState::ShallowHistory .

访问函数：

HistoryType	historyType () const
void	setHistoryType (HistoryType type )

通知程序信号：

void

historyTypeChanged ()

[见下文注意事项]

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

成员函数文档编制

QHistoryState:: QHistoryState ( QState * parent = Q_NULLPTR)

Constructs a new shallow history state with the given parent 状态。

QHistoryState:: QHistoryState ( HistoryType type , QState * parent = Q_NULLPTR)

Constructs a new history state of the given type ，采用给定 parent 状态。

QHistoryState:: ~QHistoryState ()

Destroys this history state.

QAbstractState *QHistoryState:: defaultState () const

Returns this history state's default state. The default state indicates the state to transition to if the parent state has never been entered before.

注意： Getter 函数对于特性 defaultState .

另请参阅 setDefaultState ().

[signal] void QHistoryState:: defaultStateChanged ()

此信号被发射当 defaultState 特性改变。

该函数在 Qt 5.4 引入。

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

注意： 通知程序信号对于特性 defaultState .

另请参阅 QHistoryState::defaultState .

QAbstractTransition *QHistoryState:: defaultTransition () const

Returns this history state's default transition. The default transition is taken when the history state has never been entered before. The target states of the default transition therefore make up the default state.

该函数在 Qt 5.6 引入。

注意： Getter 函数对于特性 defaultTransition .

另请参阅 setDefaultTransition ().

[signal] void QHistoryState:: defaultTransitionChanged ()

此信号被发射当 defaultTransition 特性改变。

该函数在 Qt 5.6 引入。

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

注意： 通知程序信号对于特性 defaultTransition .

另请参阅 QHistoryState::defaultTransition .

[virtual protected] bool QHistoryState:: event ( QEvent * e )

重实现自 QObject::event ().

HistoryType QHistoryState:: historyType () const

Returns the type of history that this history state records.

注意： Getter 函数对于特性 historyType .

另请参阅 setHistoryType ().

[signal] void QHistoryState:: historyTypeChanged ()

此信号被发射当 historyType 特性改变。

该函数在 Qt 5.4 引入。

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

注意： 通知程序信号对于特性 historyType .

另请参阅 QHistoryState::historyType .

[virtual protected] void QHistoryState:: onEntry ( QEvent * event )

重实现自 QAbstractState::onEntry ().

[virtual protected] void QHistoryState:: onExit ( QEvent * event )

重实现自 QAbstractState::onExit ().

void QHistoryState:: setDefaultState ( QAbstractState * state )

Sets this history state's default state to be the given state . state must be a sibling of this history state.

Note that this function does not set state as the initial state of its parent.

注意： Setter 函数对于特性 defaultState .

另请参阅 defaultState ().

void QHistoryState:: setDefaultTransition ( QAbstractTransition * transition )

Sets this history state's default transition to be the given transition . This will set the source state of the transition to the history state.

Note that the eventTest method of the transition will never be called.

该函数在 Qt 5.6 引入。

注意： Setter 函数对于特性 defaultTransition .

另请参阅 defaultTransition ().

void QHistoryState:: setHistoryType ( HistoryType type )

设置 type of history that this history state records.

注意： Setter 函数对于特性 historyType .

另请参阅 historyType ().