gtkmm: Gtk::TreeIter< T > Class Template Reference

gtkmm 4.23.0

Public Types | Public Member Functions | Related Symbols | List of all members
Gtk::TreeIter< T > Class Template Reference
TreeView Classes

Typedefed as TreeModel::iterator and TreeModel::const_iterator. More...

`#include <gtkmm/treeiter.h>`

Inheritance diagram for Gtk::TreeIter< T >:
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## Public Types
using | iterator_category = std::bidirectional_iterator_tag
| TreeIter instances can be incremented and decremented.
using | value_type = T
| The TreeRow or TreeConstRow type to which the iterator refers.
using | difference_type = int
| This is not used.
using | reference = T&
| A reference to the TreeRow or TreeConstRow type, as yielded by operator*().
using | pointer = T*
| A pointer to the TreeRow or TreeConstRow type, as yielded by operator->().

## Public Member Functions
| TreeIter ()
| Default constructor creates an invalid iterator, not referring to a model.
template<typename T2, typename = typename std::enable_if< std::is_same<T, TreeConstRow>::value && std::is_same<T2, TreeRow>::value, T2>::type>
| TreeIter (const TreeIter< T2 > & src)
| iterator to const_iterator conversion.
template<typename T2, typename = typename std::enable_if< std::is_same<T, TreeConstRow>::value && std::is_same<T2, TreeRow>::value, T2>::type>
TreeIter & | operator= (const TreeIter< T2 > & src)
| iterator to const_iterator assignment.
TreeIter & | operator++ ()
| Increment the iterator to refer to the next position in the model, and return a reference to the iterator as it is after the increment.
TreeIter | operator++ (int)
| Increment the iterator to refer to the next position in the model, but return a copy of the iterator as it was before the increment.
TreeIter & | operator-- ()
| Note that this is very slow compared to operator++().
TreeIter | operator-- (int)
| Note that this is very slow compared to operator++(int).
reference | operator* () const
| Dereference the iterator to get a TreeRow or TreeConstRow, as appropriate.
pointer | operator-> () const
| Dereference the iterator to get a TreeRow or TreeConstRow, as appropriate.
| operator bool () const
| Discover whether the iterator is valid, and not equal to end().
Public Member Functions inherited from Gtk::TreeIterBase3
bool | equal (const TreeIterBase3 & other) const
int | get_stamp () const
| This is only useful when implementing a custom Gtk::TreeModel class.
void | set_stamp (int stamp)
| This is only useful when implementing a custom Gtk::TreeModel class.
Public Member Functions inherited from Gtk::TreeIterBase
| TreeIterBase (const TreeIterBase & other) noexcept
TreeIterBase & | operator= (const TreeIterBase & other) noexcept
| TreeIterBase (TreeIterBase && other) noexcept
TreeIterBase & | operator= (TreeIterBase && other) noexcept
| TreeIterBase ()
| TreeIterBase (const GtkTreeIter * gobject)
GtkTreeIter * | gobj ()
| Provides access to the underlying C instance.
const GtkTreeIter * | gobj () const
| Provides access to the underlying C instance.

## Related Symbols
(Note that these are not member symbols.)
bool | operator== (const TreeIterBase3 & lhs, const TreeIterBase3 & rhs)
bool | operator!= (const TreeIterBase3 & lhs, const TreeIterBase3 & rhs)

## Additional Inherited Members
Static Public Member Functions inherited from Gtk::TreeIterBase
static GType | get_type ()
| Get the GType for this class, for use with the underlying GObject type system.
Protected Attributes inherited from Gtk::TreeIterBase
GtkTreeIter | gobject_

## Detailed Description

template<typename T>
class Gtk::TreeIter< T >

Typedefed as TreeModel::iterator and TreeModel::const_iterator.

A Gtk::TreeModel::iterator is a reference to a specific node on a specific model. It is a generic structure with an integer and three generic pointers. These are filled in by the model in a model-specific way.

One can convert a path to an iterator by calling Gtk::TreeModel::get_iter().

These iterators are the primary way of accessing a model and are similar to the iterators used by Gtk::TextBuffer. The model interface defines a set of operations using them for navigating the model.

The lifecycle of an iterator can be a little confusing at first. Iterators are expected to always be valid for as long as the model is unchanged (and doesn't emit a signal). Additionally, some models guarantee that an iterator is valid for as long as the node it refers to is valid (most notably the Gtk::TreeStore and Gtk::ListStore).

One can convert an iterator to a TreeRow or TreeConstRow, as appropriate, by dereferencing it via TreeIter::operator*() or TreeIter::operator->(). The row classes can give nicer syntax by avoiding repeatedly dereferencing iterators. But see the warning re: reference safety in the doc of TreeIter::operator*().

Although generally uninteresting, as one always has to allow for the case where iterators do not persist beyond a signal, some very important performance enhancements were made in the sort model. As a result, the Gtk::TreeModel::Flags::ITERS_PERSIST flag was added to indicate this behaviour - see Gtk::TreeModel::get_flags().

Template Parameters

  T | TreeRow for an iterator, TreeConstRow for a const_iterator.

Deprecated
  4.10: Use Gio::ListModel instead.

## Member Typedef Documentation

## ◆ difference_type

template <typename T>

using Gtk::TreeIter< T >::difference_type = int

This is not used.

## ◆ iterator_category

template <typename T>

using Gtk::TreeIter< T >::iterator_category = std::bidirectional_iterator_tag

TreeIter instances can be incremented and decremented.

## ◆ pointer

template <typename T>

using Gtk::TreeIter< T >::pointer = T*

A pointer to the TreeRow or TreeConstRow type, as yielded by operator->().

## ◆ reference

template <typename T>

using Gtk::TreeIter< T >::reference = T&

A reference to the TreeRow or TreeConstRow type, as yielded by operator*().

## ◆ value_type

template <typename T>

using Gtk::TreeIter< T >::value_type = T

The TreeRow or TreeConstRow type to which the iterator refers.

## Constructor & Destructor Documentation

## ◆ TreeIter() [1/2]

template <typename T>

Gtk::TreeIter< T >::TreeIter | ( |  | ) |

Default constructor creates an invalid iterator, not referring to a model.

## ◆ TreeIter() [2/2]

template <typename T>
template <typename T2, typename = typename std::enable_if< std::is_same<T, TreeConstRow>::value && std::is_same<T2, TreeRow>::value, T2>::type>

Gtk::TreeIter< T >::TreeIter | ( | const TreeIter< T2 > & | src | ) |

iterator to const_iterator conversion.

## Member Function Documentation

## ◆ operator bool()

template <typename T>

Gtk::TreeIter< T >::operator bool | ( |  | ) | const
| inlineexplicit

Discover whether the iterator is valid, and not equal to end().

For instance,

if (treeiter)
do_something();

Since gtkmm 3.22

## ◆ operator*()

template <typename T>

reference Gtk::TreeIter< T >::operator* | ( |  | ) | const
| inline

Dereference the iterator to get a TreeRow or TreeConstRow, as appropriate.

Warning: The returned reference is implemented by casting from *this, and so the returned reference is only valid while this iter is. Thus, if you do something like auto& row = *model->append(), you get a dangling reference to the returned temporary and undefined behaviour. Thus for such cases, you must copy the returned row via auto row = *model->append() or equivalent. This risk cannot be mitigated in gtkmm v4, and the class will not be in v5.

## ◆ operator++() [1/2]

template <typename T>

TreeIter & Gtk::TreeIter< T >::operator++ | ( |  | ) |

Increment the iterator to refer to the next position in the model, and return a reference to the iterator as it is after the increment.

## ◆ operator++() [2/2]

template <typename T>

TreeIter Gtk::TreeIter< T >::operator++ | ( | int |  | ) |

Increment the iterator to refer to the next position in the model, but return a copy of the iterator as it was before the increment.

## ◆ operator--() [1/2]

template <typename T>

TreeIter & Gtk::TreeIter< T >::operator-- | ( |  | ) |

Note that this is very slow compared to operator++().

Decrement the iterator to refer to the previous position in the model, and return a reference to the iterator as it is after the decrement.

## ◆ operator--() [2/2]

template <typename T>

TreeIter Gtk::TreeIter< T >::operator-- | ( | int |  | ) |

Note that this is very slow compared to operator++(int).

Decrement the iterator to refer to the previous position in the model, but return a copy of the iterator as it was before the decrement.

## ◆ operator->()

template <typename T>

pointer Gtk::TreeIter< T >::operator-> | ( |  | ) | const
| inline

Dereference the iterator to get a TreeRow or TreeConstRow, as appropriate.

## ◆ operator=()

template <typename T>
template <typename T2, typename = typename std::enable_if< std::is_same<T, TreeConstRow>::value && std::is_same<T2, TreeRow>::value, T2>::type>

TreeIter & Gtk::TreeIter< T >::operator= | ( | const TreeIter< T2 > & | src | ) |

iterator to const_iterator assignment.

## Friends And Related Symbol Documentation

## ◆ operator!=()

template <typename T>

bool operator!= | ( | const TreeIterBase3 & | lhs,
|  | const TreeIterBase3 & | rhs )
| related

## ◆ operator==()

template <typename T>

bool operator== | ( | const TreeIterBase3 & | lhs,
|  | const TreeIterBase3 & | rhs )
| related