The QDeclarativeItem class provides the most basic of all visual items in QML. 更多...
| 头： | #include <QDeclarativeItem> |
| Since: | Qt 4.7 |
| 实例化： | Item |
| 继承： | QGraphicsObject and QDeclarativeParserStatus |
| enum | TransformOrigin { TopLeft, Top, TopRight, Left, ..., BottomRight } |
|
|
| QDeclarativeItem (QDeclarativeItem * parent = 0) | |
| virtual | ~QDeclarativeItem () |
| qreal | baselineOffset () const |
| QDeclarativeItem * | childAt (qreal x , qreal y ) const |
| QRectF | childrenRect () |
| bool | clip () const |
| void | forceActiveFocus () |
| qreal | implicitHeight () const |
| qreal | implicitWidth () const |
| bool | keepMouseGrab () const |
| QScriptValue | mapFromItem (const QScriptValue & item , qreal x , qreal y ) const |
| QScriptValue | mapToItem (const QScriptValue & item , qreal x , qreal y ) const |
| QDeclarativeItem * | parentItem () const |
| void | setBaselineOffset (qreal) |
| void | setClip (bool) |
| void | setKeepMouseGrab (bool keep ) |
| void | setParentItem (QDeclarativeItem * parent ) |
| void | setSmooth (bool smooth ) |
| void | setTransformOrigin (TransformOrigin origin ) |
| bool | smooth () const |
| TransformOrigin | transformOrigin () const |
| void | implicitHeightChanged () |
| void | implicitWidthChanged () |
| virtual void | geometryChanged (const QRectF & newGeometry , const QRectF & oldGeometry ) |
| bool | heightValid () const |
| bool | isComponentComplete () const |
| void | setImplicitHeight (qreal h ) |
| void | setImplicitWidth (qreal w ) |
| bool | widthValid () const |
The QDeclarativeItem class provides the most basic of all visual items in QML.
All visual items in Qt Declarative inherit from QDeclarativeItem . Although QDeclarativeItem has no visual appearance, it defines all the properties that are common across visual items - such as the x and y position, the width and height, anchoring and key handling.
可以子类化 QDeclarativeItem to provide your own custom visual item that inherits these features. Note that, because it does not draw anything, QDeclarativeItem 设置 QGraphicsItem::ItemHasNoContents flag. If you subclass QDeclarativeItem to create a visual item, you will need to unset this flag.
Controls the point about which simple transforms like scale apply.
| 常量 | 值 | 描述 |
|---|---|---|
QDeclarativeItem::TopLeft
|
0
|
The top-left corner of the item. |
QDeclarativeItem::Top
|
1
|
The center point of the top of the item. |
QDeclarativeItem::TopRight
|
2
|
The top-right corner of the item. |
QDeclarativeItem::Left
|
3
|
The left most point of the vertical middle. |
QDeclarativeItem::Center
|
4
|
The center of the item. |
QDeclarativeItem::Right
|
5
|
The right most point of the vertical middle. |
QDeclarativeItem::BottomLeft
|
6
|
The bottom-left corner of the item. |
QDeclarativeItem::Bottom
|
7
|
The center point of the bottom of the item. |
QDeclarativeItem::BottomRight
|
8
|
The bottom-right corner of the item. |
This property holds the position of the item's baseline in local coordinates.
The baseline of a Text item is the imaginary line on which the text sits. Controls containing text usually set their baseline to the baseline of their text.
For non-text items, a default baseline offset of 0 is used.
访问函数：
| qreal | baselineOffset () const |
| void | setBaselineOffset (qreal) |
This property holds the geometry of an item's children.
This property holds the (collective) position and size of the item's children.
访问函数：
| QRectF | childrenRect () |
This property holds whether clipping is enabled. The default clip value is
false
.
If clipping is enabled, an item will clip its own painting, as well as the painting of its children, to its bounding rectangle. If you set clipping during an item's paint operation, remember to re-set it to prevent clipping the rest of your scene.
Non-rectangular clipping regions are not supported for performance reasons.
访问函数：
| bool | clip () const |
| void | setClip (bool) |
访问函数：
| qreal | implicitHeight () const |
通知程序信号：
| void | implicitHeightChanged () |
访问函数：
| qreal | implicitWidth () const |
通知程序信号：
| void | implicitWidthChanged () |
This property holds the parent of the item.
访问函数：
| QDeclarativeItem * | parentItem () const |
| void | setParentItem (QDeclarativeItem * parent ) |
通知程序信号：
| void | parentChanged () |
This property holds whether the item is smoothly transformed.
This property is provided purely for the purpose of optimization. Turning smooth transforms off is faster, but looks worse; turning smooth transformations on is slower, but looks better.
By default smooth transformations are off.
访问函数：
| bool | smooth () const |
| void | setSmooth (bool smooth ) |
构造 QDeclarativeItem 采用给定 parent .
[虚拟]
QDeclarativeItem::
~QDeclarativeItem
()
销毁 QDeclarativeItem .
Returns the visible child item at point ( x , y ), which is in this item's coordinate system, or 0 if there is no such item.
Forces active focus on the item.
This method sets focus on the item and makes sure that all the focus scopes higher in the object hierarchy are also given the focus.
[virtual protected]
void
QDeclarativeItem::
geometryChanged
(const
QRectF
&
newGeometry
, const
QRectF
&
oldGeometry
)
This function is called to handle this item's changes in geometry from oldGeometry to newGeometry . If the two geometries are the same, it doesn't do anything.
[protected]
bool
QDeclarativeItem::
heightValid
() const
Returns whether the height property has been set explicitly.
[protected]
bool
QDeclarativeItem::
isComponentComplete
() const
Returns true if construction of the QML component is complete; otherwise returns false.
It is often desirable to delay some processing until the component is completed.
另请参阅 componentComplete ().
Returns a value indicating whether mouse input should remain with this item exclusively.
另请参阅 setKeepMouseGrab ().
Maps the point (
x
,
y
), which is in
item
's coordinate system, to this item's coordinate system, and returns a script value with
x
and
y
properties matching the mapped cooordinate.
若
item
是
null
value, this maps the point from the coordinate system of the root QML view.
另请参阅 Item::mapFromItem ().
Maps the point (
x
,
y
), which is in this item's coordinate system, to
item
's coordinate system, and returns a script value with
x
and
y
properties matching the mapped cooordinate.
若
item
是
null
value, this maps
x
and
y
to the coordinate system of the root QML view.
另请参阅 Item::mapToItem ().
[protected]
void
QDeclarativeItem::
setImplicitHeight
(
qreal
h
)
Sets the implied height of the item to h . This is the height implied by other properties that determine the content.
另请参阅 implicitHeight ().
[protected]
void
QDeclarativeItem::
setImplicitWidth
(
qreal
w
)
Sets the implied width of the item to w . This is the width implied by other properties that determine the content.
另请参阅 implicitWidth ().
The flag indicating whether the mouse should remain with this item is set to keep .
This is useful for items that wish to grab and keep mouse interaction following a predefined gesture. For example, an item that is interested in horizontal mouse movement may set keepMouseGrab to true once a threshold has been exceeded. Once keepMouseGrab has been set to true, filtering items will not react to mouse events.
If the item does not indicate that it wishes to retain mouse grab, a filtering item may steal the grab. For example, Flickable may attempt to steal a mouse grab if it detects that the user has begun to move the viewport.
另请参阅 keepMouseGrab ().
Set the transform origin .
另请参阅 transformOrigin ().
Returns the current transform origin.
另请参阅 setTransformOrigin ().
[protected]
bool
QDeclarativeItem::
widthValid
() const
Returns whether the width property has been set explicitly.