The QModelIndex class is used to locate data in a data model. 更多...
| 头： | #include <QModelIndex> |
| qmake: | QT += core |
| QModelIndex () | |
| int | column () const |
| QVariant | data (int role = Qt::DisplayRole) const |
| Qt::ItemFlags | flags () const |
| quintptr | internalId () const |
| void * | internalPointer () const |
| bool | isValid () const |
| const QAbstractItemModel * | model () const |
| QModelIndex | parent () const |
| int | row () const |
| QModelIndex | sibling (int row , int column ) const |
| bool | operator!= (const QModelIndex & other ) const |
| bool | operator< (const QModelIndex & other ) const |
| bool | operator== (const QModelIndex & other ) const |
| typedef | QModelIndexList |
The QModelIndex class is used to locate data in a data model.
此类被用作项模型的索引，派生自 QAbstractItemModel . The index is used by item views, delegates, and selection models to locate an item in the model.
New QModelIndex objects are created by the model using the QAbstractItemModel::createIndex () function. An invalid model index can be constructed with the QModelIndex constructor. Invalid indexes are often used as parent indexes when referring to top-level items in a model.
Model indexes refer to items in models, and contain all the information required to specify their locations in those models. Each index is located in a given row and column, and may have a parent index; use row (), column ()，和 parent () to obtain this information. Each top-level item in a model is represented by a model index that does not have a parent index - in this case, parent () will return an invalid model index, equivalent to an index constructed with the zero argument form of the QModelIndex () constructor.
To obtain a model index that refers to an existing item in a model, call QAbstractItemModel::index () with the required row and column values, and the model index of the parent. When referring to top-level items in a model, supply QModelIndex () as the parent index.
The model () function returns the model that the index references as a QAbstractItemModel . The child() function is used to examine items held under the index in the model. The sibling () function allows you to traverse items in the model on the same level as the index.
注意： Model indexes should be used immediately and then discarded. You should not rely on indexes to remain valid after calling model functions that change the structure of the model or delete items. If you need to keep a model index over time use a QPersistentModelIndex .
另请参阅 模型/视图编程 , QPersistentModelIndex ，和 QAbstractItemModel .
Creates a new empty model index. This type of model index is used to indicate that the position in the model is invalid.
另请参阅 isValid () 和 QAbstractItemModel .
Returns the column this model index refers to.
返回数据为给定 role for the item referred to by the index.
Returns the flags for the item referred to by the index.
该函数在 Qt 4.2 引入。
返回
quintptr
used by the model to associate the index with the internal data structure.
另请参阅 QAbstractItemModel::createIndex ().
返回
void
*
pointer used by the model to associate the index with the internal data structure.
另请参阅 QAbstractItemModel::createIndex ().
返回
true
若此模型索引有效；否则返回
false
.
A valid index belongs to a model, and has non-negative row and column numbers.
另请参阅 model (), row ()，和 column ().
Returns a pointer to the model containing the item that this index refers to.
A const pointer to the model is returned because calls to non-const functions of the model might invalidate the model index and possibly crash your application.
Returns the parent of the model index, or QModelIndex () if it has no parent.
Returns the row this model index refers to.
返回同级在 row and column . If there is no sibling at this position, an invalid QModelIndex 被返回。
另请参阅 parent ().
返回
true
if this model index does not refer to the same location as the
other
model index; otherwise returns
false
.
返回
true
if this model index is smaller than the
other
model index; otherwise returns
false
.
The less than calculation is not directly useful to developers - the way that indexes with different parents compare is not defined. This operator only exists so that the class can be used with QMap .
该函数在 Qt 4.1 引入。
返回
true
if this model index refers to the same location as the
other
model index; otherwise returns
false
.
All values in the model index are used when comparing with another model index.
同义词 QList < QModelIndex >.
