Package org.gnome.gtk

Interface SelectionModel<T extends GObject>

All Superinterfaces:

Collection<T>, Iterable<T>, List<T>, ListModel<T>, ListModelJavaList<T>, Proxy, SequencedCollection<T>

All Known Implementing Classes:

MultiSelection, NoSelection, SelectionModel.SelectionModel$Impl, SingleSelection, ViewStackPages

@Generated("io.github.jwharm.JavaGI")
public interface SelectionModel<T extends GObject>
extends Proxy, ListModel<T>

An interface that adds support for selection to list models.

This support is then used by widgets using list models to add the ability to select and unselect various items.

GTK provides default implementations of the most common selection modes such as SingleSelection, so you will only need to implement this interface if you want detailed control about how selections should be handled.

A GtkSelectionModel supports a single boolean per item indicating if an item is selected or not. This can be queried via isSelected(int). When the selected state of one or more items changes, the model will emit the Gtk.SelectionModel::selection-changed signal by calling the selectionChanged(int, int) function. The positions given in that signal may have their selection state changed, though that is not a requirement. If new items added to the model via the Gio.ListModel::items-changed signal are selected or not is up to the implementation.

Note that items added via Gio.ListModel::items-changed may already be selected and no Gtk.SelectionModel::selection-changed will be emitted for them. So to track which items are selected, it is necessary to listen to both signals.

Additionally, the interface can expose functionality to select and unselect items. If these functions are implemented, GTK's list widgets will allow users to select and unselect items. However, GtkSelectionModels are free to only implement them partially or not at all. In that case the widgets will not support the unimplemented operations.

When selecting or unselecting is supported by a model, the return values of the selection functions do not indicate if selection or unselection happened. They are only meant to indicate complete failure, like when this mode of selecting is not supported by the model.

Selections may happen asynchronously, so the only reliable way to find out when an item was selected is to listen to the signals that indicate selection.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	SelectionModel.SelectionChangedCallback	Functional interface declaration of the SelectionChangedCallback callback.
static class	SelectionModel.SelectionModel$Impl	The SelectionModel$Impl type represents a native instance of the SelectionModel interface.
static class	SelectionModel.SelectionModelInterface	The list of virtual functions for the GtkSelectionModel interface.

Nested classes/interfaces inherited from interface org.gnome.gio.ListModel

ListModel.ItemsChangedCallback, ListModel.ListModel$Impl, ListModel.ListModelInterface

Nested classes/interfaces inherited from interface org.javagi.gio.ListModelJavaList

ListModelJavaList.SubList<E extends @Nullable GObject,List extends ListModelJavaList<E>>

Method Summary

Modifier and Type	Method	Description
default void	emitSelectionChanged(int position, int nItems)	Emits the "selection-changed" signal.
default Bitset	getSelection()	Gets the set containing all currently selected items in the model.
default Bitset	getSelectionInRange(int position, int nItems)	Gets the set of selected items in a range.
static @Nullable Type	getType()	Get the GType of the SelectionModel class
default boolean	isSelected(int position)	Checks if the given item is selected.
default SignalConnection<SelectionModel.SelectionChangedCallback>	onSelectionChanged(SelectionModel.SelectionChangedCallback handler)	Emitted when the selection state of some of the items in model changes.
default boolean	selectAll()	Requests to select all items in the model.
default void	selectionChanged(int position, int nItems)	Helper function for implementations of GtkSelectionModel.
default boolean	selectItem(int position, boolean unselectRest)	Requests to select an item in the model.
default boolean	selectRange(int position, int nItems, boolean unselectRest)	Requests to select a range of items in the model.
default boolean	setSelection(Bitset selected, Bitset mask)	Make selection changes.
default boolean	unselectAll()	Requests to unselect all items in the model.
default boolean	unselectItem(int position)	Requests to unselect an item in the model.
default boolean	unselectRange(int position, int nItems)	Requests to unselect a range of items in the model.

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.List

addFirst, addLast, equals, getFirst, getLast, hashCode, removeFirst, removeLast, replaceAll, reversed, sort, spliterator

Methods inherited from interface org.gnome.gio.ListModel

emitItemsChanged, getItem, getItemType, getNItems, itemsChanged, onItemsChanged

Methods inherited from interface org.javagi.gio.ListModelJavaList

add, add, addAll, addAll, clear, contains, containsAll, get, indexOf, isEmpty, iterator, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, retainAll, set, size, subList, toArray, toArray

Methods inherited from interface org.javagi.base.Proxy

handle

Method Details

getType

static @Nullable Type getType()

Get the GType of the SelectionModel class

Returns:

the GType

getSelection

default Bitset getSelection()

Gets the set containing all currently selected items in the model.

This function may be slow, so if you are only interested in single item, consider using isSelected(int) or if you are only interested in a few, consider getSelectionInRange(int, int).

Returns:

a GtkBitset containing all the values currently selected in model. If no items are selected, the bitset is empty. The bitset must not be modified.

getSelectionInRange

default Bitset getSelectionInRange(int position,
 int nItems)

Gets the set of selected items in a range.

This function is an optimization for getSelection() when you are only interested in part of the model's selected state. A common use case is in response to the Gtk.SelectionModel::selection-changed signal.

Parameters:

position - start of the queried range

nItems - number of items in the queried range

Returns:

A GtkBitset that matches the selection state for the given range with all other values being undefined. The bitset must not be modified.

isSelected

default boolean isSelected(int position)

Checks if the given item is selected.

Parameters:

position - the position of the item to query

Returns:

true if the item is selected

selectAll

default boolean selectAll()

Requests to select all items in the model.

Returns:

true if this action was supported and no fallback should be tried. This does not mean that all items are now selected.

selectItem

default boolean selectItem(int position,
 boolean unselectRest)

Requests to select an item in the model.

Parameters:

position - the position of the item to select

unselectRest - whether previously selected items should be unselected

Returns:

true if this action was supported and no fallback should be tried. This does not mean the item was selected.

selectRange

default boolean selectRange(int position,
 int nItems,
 boolean unselectRest)

Requests to select a range of items in the model.

Parameters:

position - the first item to select

nItems - the number of items to select

unselectRest - whether previously selected items should be unselected

Returns:

true if this action was supported and no fallback should be tried. This does not mean the range was selected.

selectionChanged

default void selectionChanged(int position,
 int nItems)

Helper function for implementations of GtkSelectionModel.

Call this when the selection changes to emit the Gtk.SelectionModel::selection-changed signal.

Parameters:

position - the first changed item

nItems - the number of changed items

setSelection

default boolean setSelection(Bitset selected,
 Bitset mask)

Make selection changes.

This is the most advanced selection updating method that allows the most fine-grained control over selection changes. If you can, you should try the simpler versions, as implementations are more likely to implement support for those.

Requests that the selection state of all positions set in mask be updated to the respective value in the selected bitmask.

In pseudocode, it would look something like this:

for (i = 0; i < n_items; i++)
   {
     // don't change values not in the mask
     if (!gtk_bitset_contains (mask, i))
       continue;

     if (gtk_bitset_contains (selected, i))
       select_item (i);
     else
       unselect_item (i);
   }

 gtk_selection_model_selection_changed (model,
                                        first_changed_item,
                                        n_changed_items);
 

mask and selected must not be modified. They may refer to the same bitset, which would mean that every item in the set should be selected.

Parameters:

selected - bitmask specifying if items should be selected or unselected

mask - bitmask specifying which items should be updated

Returns:

true if this action was supported and no fallback should be tried. This does not mean that all items were updated according to the inputs.

unselectAll

default boolean unselectAll()

Requests to unselect all items in the model.

Returns:

true if this action was supported and no fallback should be tried. This does not mean that all items are now unselected.

unselectItem

default boolean unselectItem(int position)

Requests to unselect an item in the model.

Parameters:

position - the position of the item to unselect

Returns:

true if this action was supported and no fallback should be tried. This does not mean the item was unselected.

unselectRange

default boolean unselectRange(int position,
 int nItems)

Requests to unselect a range of items in the model.

Parameters:

position - the first item to unselect

nItems - the number of items to unselect

Returns:

true if this action was supported and no fallback should be tried. This does not mean the range was unselected.

onSelectionChanged

default SignalConnection<SelectionModel.SelectionChangedCallback> onSelectionChanged(SelectionModel.SelectionChangedCallback handler)

Emitted when the selection state of some of the items in model changes.

Note that this signal does not specify the new selection state of the items, they need to be queried manually. It is also not necessary for a model to change the selection state of any of the items in the selection model, though it would be rather useless to emit such a signal.

Parameters:

handler - the signal handler

Returns:

a signal handler ID to keep track of the signal connection

See Also:

• SelectionModel.SelectionChangedCallback.run(int, int)

emitSelectionChanged

default void emitSelectionChanged(int position,
 int nItems)

Emits the "selection-changed" signal. See onSelectionChanged(org.gnome.gtk.SelectionModel.SelectionChangedCallback).