KDE API Reference

Contents

KModelIndexProxyMapper Class

This class facilitates easy mapping of indexes and selections through proxy models. More...

Header: #include <KModelIndexProxyMapper>
CMake: find_package(KF6 REQUIRED COMPONENTS ItemModels)
target_link_libraries(mytarget PRIVATE KF6::ItemModels)

Properties

Public Functions

KModelIndexProxyMapper(const QAbstractItemModel *leftModel, const QAbstractItemModel *rightModel, QObject *parent = nullptr)
bool isConnected() const
QModelIndex mapLeftToRight(const QModelIndex &index) const
QModelIndex mapRightToLeft(const QModelIndex &index) const
QItemSelection mapSelectionLeftToRight(const QItemSelection &selection) const
QItemSelection mapSelectionRightToLeft(const QItemSelection &selection) const

Signals

void isConnectedChanged()

Detailed Description

In a complex system of proxy models there can be a need to map indexes and selections between them, and sometimes to do so without knowledge of the path from one model to another.

For example,

  Root model
      |
    /    \
Proxy 1   Proxy 3
   |       |
Proxy 2   Proxy 4

If there is a need to map indexes between proxy 2 and proxy 4, a KModelIndexProxyMapper can be created to facilitate mapping of indexes between them.

 m_indexMapper = new KModelIndexProxyMapper(proxy2, proxy4, this);

...

 const QModelIndex proxy4Index = m_mapLeftToRight(proxy2->index(0, 0));
 Q_ASSERT(proxy4Index.model() == proxy4);

Note that the aim is to achieve black box connections so that there is no need for application code to know the structure of proxy models in the path between left and right and attempt to manually map them.

  Root model
      |
---------------
|  Black Box  |
---------------
   |       |
Proxy 2   Proxy 4

The isConnected property indicates whether there is a path from the left side to the right side.

@author Stephen Kelly <steveire@gmail.com>

Property Documentation

[read-only] isConnected : const bool

Indicates whether there is a chain that can be followed from leftModel to rightModel.

This value can change if the sourceModel of an intermediate proxy is changed.

Access functions:

bool isConnected() const

Notifier signal:

void isConnectedChanged()

Member Function Documentation

KModelIndexProxyMapper::KModelIndexProxyMapper(const QAbstractItemModel *leftModel, const QAbstractItemModel *rightModel, QObject *parent = nullptr)

Constructor

QModelIndex KModelIndexProxyMapper::mapLeftToRight(const QModelIndex &index) const

Maps the index from the left model to the right model.

QModelIndex KModelIndexProxyMapper::mapRightToLeft(const QModelIndex &index) const

Maps the index from the right model to the left model.

QItemSelection KModelIndexProxyMapper::mapSelectionLeftToRight(const QItemSelection &selection) const

Maps the selection from the left model to the right model.

QItemSelection KModelIndexProxyMapper::mapSelectionRightToLeft(const QItemSelection &selection) const

Maps the selection from the right model to the left model.