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公共类型
特性
公共函数
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>
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 *
historyType : HistoryType

1 特性继承自 QObject

公共函数

	QHistoryState (QState * parent = 0)
	QHistoryState (HistoryType type , QState * parent = 0)
	~QHistoryState ()
QAbstractState *	defaultState () const
HistoryType	historyType () const
void	setDefaultState (QAbstractState * state )
void	setHistoryType (HistoryType type )

2 公共函数继承自 QAbstractState
29 公共函数继承自 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
8 保护函数继承自 QObject

额外继承成员

1 公共槽继承自 QObject
2 信号继承自 QAbstractState
1 信号继承自 QObject
7 静态公共成员继承自 QObject
3 保护函数继承自 QAbstractState
8 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 of the 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);

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 )

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 )

成员函数文档编制

QHistoryState:: QHistoryState ( QState * parent = 0)

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

QHistoryState:: QHistoryState ( HistoryType type , QState * parent = 0)

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

QHistoryState:: ~QHistoryState ()

Destroys this history state.

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

重实现自 QObject::event ().

`[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 ().

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