The QScxmlNullDataModel class is the null data model for a Qt SCXML stateMachine . 更多...
| 头： | #include <QScxmlNullDataModel> |
| qmake: | QT += scxml |
| Since: | Qt 5.7 |
| 继承： | QScxmlDataModel |
该类在 Qt 5.7 引入。
| QScxmlNullDataModel (QObject * parent = nullptr) | |
| virtual | ~QScxmlNullDataModel () |
| virtual void | evaluateAssignment (QScxmlExecutableContent::EvaluatorId id , bool * ok ) override |
| virtual void | evaluateForeach (QScxmlExecutableContent::EvaluatorId id , bool * ok , QScxmlDataModel::ForeachLoopBody * body ) override |
| virtual void | evaluateInitialization (QScxmlExecutableContent::EvaluatorId id , bool * ok ) override |
| virtual bool | evaluateToBool (QScxmlExecutableContent::EvaluatorId id , bool * ok ) override |
| virtual QString | evaluateToString (QScxmlExecutableContent::EvaluatorId id , bool * ok ) override |
| virtual QVariant | evaluateToVariant (QScxmlExecutableContent::EvaluatorId id , bool * ok ) override |
| virtual void | evaluateToVoid (QScxmlExecutableContent::EvaluatorId id , bool * ok ) override |
| virtual bool | hasScxmlProperty (const QString & name ) const override |
| virtual QVariant | scxmlProperty (const QString & name ) const override |
| virtual void | setScxmlEvent (const QScxmlEvent & event ) override |
| virtual bool | setScxmlProperty (const QString & name , const QVariant & value , const QString & context ) override |
| virtual bool | setup (const QVariantMap & initialDataValues ) override |
This class implements the null data model as described in the
SCXML Specification - B.1 The Null Data Model
. Using the value
"null"
为
datamodel
属性在
<scxml>
element means that there is no underlying data model, but some executable content, like
In(...)
or
<log>
can still be used.
另请参阅 QScxmlStateMachine and QScxmlDataModel .
Creates a new Qt SCXML null data model, with the parent object parent .
[虚拟]
QScxmlNullDataModel::
~QScxmlNullDataModel
()
Destroys the data model.
[override virtual]
void
QScxmlNullDataModel::
evaluateAssignment
(
QScxmlExecutableContent::EvaluatorId
id
,
bool
*
ok
)
重实现： QScxmlDataModel::evaluateAssignment (QScxmlExecutableContent::EvaluatorId id, bool *ok).
Throws an error and sets
ok
to
false
, because the null data model cannot evaluate assignments.
[override virtual]
void
QScxmlNullDataModel::
evaluateForeach
(
QScxmlExecutableContent::EvaluatorId
id
,
bool
*
ok
,
QScxmlDataModel::ForeachLoopBody
*
body
)
重实现： QScxmlDataModel::evaluateForeach (QScxmlExecutableContent::EvaluatorId id, bool *ok, QScxmlDataModel::ForeachLoopBody *body).
Throws an error and sets
ok
to
false
, because the null data model cannot evaluate
<foreach>
blocks.
[override virtual]
void
QScxmlNullDataModel::
evaluateInitialization
(
QScxmlExecutableContent::EvaluatorId
id
,
bool
*
ok
)
重实现： QScxmlDataModel::evaluateInitialization (QScxmlExecutableContent::EvaluatorId id, bool *ok).
Throws an error and sets
ok
to
false
, because the null data model cannot initialize data.
[override virtual]
bool
QScxmlNullDataModel::
evaluateToBool
(
QScxmlExecutableContent::EvaluatorId
id
,
bool
*
ok
)
重实现： QScxmlDataModel::evaluateToBool (QScxmlExecutableContent::EvaluatorId id, bool *ok).
Evaluates the executable content pointed to by
id
and records in
ok
whether there was an error. Returns the result of the evaluation as a boolean value. The null data model can evaluate the instruction
In(...)
, so this might result in an actual value, rather than an error.
[override virtual]
QString
QScxmlNullDataModel::
evaluateToString
(
QScxmlExecutableContent::EvaluatorId
id
,
bool
*
ok
)
重实现： QScxmlDataModel::evaluateToString (QScxmlExecutableContent::EvaluatorId id, bool *ok).
Evaluates the executable content pointed to by
id
and records in
ok
whether there was an error. Returns the result of the evaluation as a string. The null data model can evaluate the
<log>
element, so this might result in an actual value, rather than an error
[override virtual]
QVariant
QScxmlNullDataModel::
evaluateToVariant
(
QScxmlExecutableContent::EvaluatorId
id
,
bool
*
ok
)
重实现： QScxmlDataModel::evaluateToVariant (QScxmlExecutableContent::EvaluatorId id, bool *ok).
Evaluates the executable content pointed to by
id
and records in
ok
whether there was an error. As this is the null data model, any evaluation will in fact result in an error, with
ok
设为
false
. Returns an empty
QVariant
.
[override virtual]
void
QScxmlNullDataModel::
evaluateToVoid
(
QScxmlExecutableContent::EvaluatorId
id
,
bool
*
ok
)
重实现： QScxmlDataModel::evaluateToVoid (QScxmlExecutableContent::EvaluatorId id, bool *ok).
Evaluates the executable content pointed to by
id
and records in
ok
whether there was an error. As this is the null data model, any evaluation will in fact result in an error, with
ok
设为
false
.
[override virtual]
bool
QScxmlNullDataModel::
hasScxmlProperty
(const
QString
&
name
) const
重实现： QScxmlDataModel::hasScxmlProperty (const QString &name) const.
返回
false
, because the null data model does not support properties.
[override virtual]
QVariant
QScxmlNullDataModel::
scxmlProperty
(const
QString
&
name
) const
重实现： QScxmlDataModel::scxmlProperty (const QString &name) const.
Returns an invalid variant, because the null data model does not support properties.
另请参阅 setScxmlProperty ().
[override virtual]
void
QScxmlNullDataModel::
setScxmlEvent
(const
QScxmlEvent
&
event
)
重实现： QScxmlDataModel::setScxmlEvent (const QScxmlEvent &event).
Does not actually set the event , because the null data model does not handle events.
[override virtual]
bool
QScxmlNullDataModel::
setScxmlProperty
(const
QString
&
name
, const
QVariant
&
value
, const
QString
&
context
)
重实现： QScxmlDataModel::setScxmlProperty (const QString &name, const QVariant &value, const QString &context).
返回
false
, because the null data model does not support properties.
另请参阅 scxmlProperty ().
[override virtual]
bool
QScxmlNullDataModel::
setup
(const
QVariantMap
&
initialDataValues
)
重实现： QScxmlDataModel::setup (const QVariantMap &initialDataValues).