Sorter

class Sorter(**properties: Any)

Superclasses: Object

Subclasses: ColumnViewSorter, CustomSorter, MultiSorter, NumericSorter, StringSorter, TreeListRowSorter

GtkSorter is an object to describe sorting criteria.

Its primary user is SortListModel

The model will use a sorter to determine the order in which its items should appear by calling compare for pairs of items.

Sorters may change their sorting behavior through their lifetime. In that case, they will emit the changed signal to notify that the sort order is no longer valid and should be updated by calling compare() again.

GTK provides various pre-made sorter implementations for common sorting operations. ColumnView has built-in support for sorting lists via the sorter property, where the user can change the sorting by clicking on list headers.

Of course, in particular for large lists, it is also possible to subclass GtkSorter and provide one’s own sorter.

Methods

class Sorter
changed(change: SorterChange) → None

Notifies all users of the sorter that it has changed.

This emits the changed signal. Users of the sorter should then update the sort order via compare.

Depending on the change parameter, it may be possible to update the sort order without a full resorting. Refer to the SorterChange documentation for details.

This function is intended for implementers of GtkSorter subclasses and should not be called from other functions.

Parameters:

change – How the sorter changed

compare(item1: Object, item2: Object) → Ordering

Compares two given items according to the sort order implemented by the sorter.

Sorters implement a partial order:

  • It is reflexive, ie a = a

  • It is antisymmetric, ie if a < b and b < a, then a = b

  • It is transitive, ie given any 3 items with a ≤ b and b ≤ c, then a ≤ c

The sorter may signal it conforms to additional constraints via the return value of get_order.

Parameters:

  • item1 – first item to compare

  • item2 – second item to compare

get_order() → SorterOrder

Gets the order that self conforms to.

See SorterOrder for details of the possible return values.

This function is intended to allow optimizations.

Signals

class Sorter.signals
changed(change: SorterChange) → None

Emitted whenever the sorter changed.

Users of the sorter should then update the sort order again via compare().

SortListModel handles this signal automatically.

Depending on the change parameter, it may be possible to update the sort order without a full resorting. Refer to the SorterChange documentation for details.

Parameters:

change – how the sorter changed

Virtual Methods

class Sorter
do_compare(item1: Object | None = None, item2: Object | None = None) → Ordering

Compares two given items according to the sort order implemented by the sorter.

Sorters implement a partial order:

  • It is reflexive, ie a = a

  • It is antisymmetric, ie if a < b and b < a, then a = b

  • It is transitive, ie given any 3 items with a ≤ b and b ≤ c, then a ≤ c

The sorter may signal it conforms to additional constraints via the return value of get_order.

Parameters:

  • item1 – first item to compare

  • item2 – second item to compare

do_get_order() → SorterOrder

Gets the order that self conforms to.

See SorterOrder for details of the possible return values.

This function is intended to allow optimizations.

Fields

class Sorter
parent_instance