QXmlNodeModelIndex class identifies a node in an XML node model subclassed from QAbstractXmlNodeModel . 更多...
| 头： | #include <QXmlNodeModelIndex> |
| qmake: | QT += xmlpatterns |
| Since: | Qt 4.4 |
注意： 此类的所有函数 可重入 .
| enum | DocumentOrder { Precedes, Follows, Is } |
| typedef | List |
| enum | NodeKind { Attribute, Text, Comment, Document, ..., ProcessingInstruction } |
| QXmlNodeModelIndex () | |
| QXmlNodeModelIndex (const QXmlNodeModelIndex & other ) | |
| qint64 | additionalData () const |
| qint64 | data () const |
| void * | internalPointer () const |
| bool | isNull () const |
| const QAbstractXmlNodeModel * | model () const |
| bool | operator!= (const QXmlNodeModelIndex & other ) const |
| QXmlNodeModelIndex & | operator= ( const QXmlNodeModelIndex & ) = default |
| bool | operator== (const QXmlNodeModelIndex & other ) const |
QXmlNodeModelIndex class identifies a node in an XML node model subclassed from QAbstractXmlNodeModel .
QXmlNodeModelIndex is an index into an XML node model . It contains:
因为 QXmlNodeModelIndex is intentionally a simple class, it doesn't have member functions for accessing the properties of nodes. For example, it doesn't have functions for getting a node's name or its list of attributes or child nodes. If you find that you need to retrieve this kind of information from your query results, there are two ways to proceed.
The second case is explained by example. Suppose you want to populate a list widget with the values of certain attributes from a set of result elements. You could write an XQuery to return the set of elements, and then you would write the code to iterate over the result elements, get their attributes, and extract the desired string values. But the simpler way is to just augment your XQuery to finding the desired attribute values. Then all you have to do is evaluate the XQuery using the version of QXmlQuery::evaluateTo () that populates a QStringList , which you can send directly to your widget.
QXmlNodeModelIndex
doesn't impose any restrictions on the
data
value an
QXmlNodeModelIndex
should contain. The meaning of the data left to the associated
node model
. Because
QXmlNodeModelIndex
depends on a particular subclass of
QAbstractXmlNodeModel
for its existence, the only way you can create an instance of
QXmlNodeModelIndex
is by asking the node model to create one for you with
QAbstractXmlNodeModel::createIndex
(). Since that function is protected, it is usually a good idea to write a public function that creates a
QXmlNodeModelIndex
from arguments that are appropriate for your particular node model.
A default constructed node index is said to be null, i.e., isNull () returns true.
QXmlNodeModelIndex and QAbstractXmlNodeModel follow the same design pattern used for QModelIndex and QAbstractItemModel .
Identifies the specific node comparison operator that should be used.
| 常量 | 值 | 描述 |
|---|---|---|
QXmlNodeModelIndex::Precedes
|
-1
|
Signifies the
\<\<
operator. Test whether the first operand precedes the second in the document.
|
QXmlNodeModelIndex::Follows
|
1
|
Signifies the
\>\>
operator. Test whether the first operand follows the second in the document.
|
QXmlNodeModelIndex::Is
|
0
|
Signifies the
is
operator. Test whether two nodes have the same node identity.
|
Typedef 为 QList < QXmlNodeModelIndex >.
Identifies a kind of node.
| 常量 | 值 | 描述 |
|---|---|---|
QXmlNodeModelIndex::Attribute
|
1
|
Identifies an attribute node |
QXmlNodeModelIndex::Text
|
64
|
Identifies a text node |
QXmlNodeModelIndex::Comment
|
2
|
Identifies a comment node |
QXmlNodeModelIndex::Document
|
4
|
Identifies a document node |
QXmlNodeModelIndex::Element
|
8
|
Identifies an element node |
QXmlNodeModelIndex::Namespace
|
16
|
Identifies a namespace node |
QXmlNodeModelIndex::ProcessingInstruction
|
32
|
Identifies a processing instruction. |
Note that the optional XML declaration at very beginning of the XML document is not a processing instruction
另请参阅 QAbstractXmlNodeModel::kind ().
Default constructor. Creates an item that is
null
.
另请参阅 isNull ().
Standard copy constructor. Creates a QXmlNodeModelIndex instance that is a copy of other .
Returns the second data value. The node index holds two data values. data () returns the first one.
另请参阅 data ().
Returns the first data value. The node index holds two data values. additionalData () returns the second one.
另请参阅 additionalData ().
Returns the first data value as a void* pointer.
另请参阅 additionalData ().
返回 true，若此 QXmlNodeModelIndex is a default constructed value, otherwise false.
A null QXmlNodeModelIndex doesn't represent any node and cannot be used in conjunction with QAbstractXmlNodeModel .
返回 QAbstractXmlNodeModel that this node index refers to. QXmlNodeModelIndex does not own QAbstractXmlNodeModel and does not keep track of its lifetime, so this pointer will dangle if the QAbstractXmlNodeModel is deallocated first.
There is no setter for the node model because instances of QXmlNodeModelIndex instances are only created with QAbstractXmlNodeModel::createIndex ().
返回 true 若 other is the same node as this.
[default]
QXmlNodeModelIndex
&QXmlNodeModelIndex::
operator=
(
const QXmlNodeModelIndex &
)
Copy-assignment operator.
Returns true if this node is the same as other . This operator does not compare values, children, or names of nodes. It compares node identities, i.e., whether two nodes are from the same document and are found at the exact same place.