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GtkSelectionModelGtkSelectionModel — An extension of the list model interface that handles selections |
Functions
| gboolean | gtk_selection_model_is_selected () |
| GtkBitset * | gtk_selection_model_get_selection () |
| GtkBitset * | gtk_selection_model_get_selection_in_range () |
| gboolean | gtk_selection_model_select_item () |
| gboolean | gtk_selection_model_unselect_item () |
| gboolean | gtk_selection_model_select_range () |
| gboolean | gtk_selection_model_unselect_range () |
| gboolean | gtk_selection_model_select_all () |
| gboolean | gtk_selection_model_unselect_all () |
| gboolean | gtk_selection_model_set_selection () |
| void | gtk_selection_model_selection_changed () |
Known Implementations
GtkSelectionModel is implemented by GtkMultiSelection, GtkNoSelection and GtkSingleSelection.
Description
GtkSelectionModel is an interface that extends the GListModel interface by adding support for selections. 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 GtkSingleSelection, 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 gtk_selection_model_is_selected().
When the selected state of one or more items changes, the model will emit the
“selection-changed” signal by calling the
gtk_selection_model_selection_changed() 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 “items-changed” signal are
selected or not is up to the implementation.
Note that items added via “items-changed” may already be selected and no “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.
Functions
gtk_selection_model_is_selected ()
gboolean gtk_selection_model_is_selected (GtkSelectionModel *model,guint position);
Checks if the given item is selected.
gtk_selection_model_get_selection ()
GtkBitset *
gtk_selection_model_get_selection (GtkSelectionModel *model);
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 gtk_selection_model_is_selected() or if you are only
interested in a few consider gtk_selection_model_get_selection_in_range().
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.
[transfer full]
gtk_selection_model_get_selection_in_range ()
GtkBitset * gtk_selection_model_get_selection_in_range (GtkSelectionModel *model,guint position,guint n_items);
Gets a set containing a set where the values in the range [position,
position + n_items) match the selected state of the items in that range.
All values outside that range are undefined.
This function is an optimization for gtk_selection_model_get_selection() when
you are only interested in part of the model's selected state. A common use
case is in response to the “selection-changed” signal.
Returns
A GtkBitset that matches the selection state for the given state with all other values being undefined. The bitset must not be modified.
gtk_selection_model_select_item ()
gboolean gtk_selection_model_select_item (GtkSelectionModel *model,guint position,gboolean unselect_rest);
Requests to select an item in the model.
gtk_selection_model_unselect_item ()
gboolean gtk_selection_model_unselect_item (GtkSelectionModel *model,guint position);
Requests to unselect an item in the model.
gtk_selection_model_select_range ()
gboolean gtk_selection_model_select_range (GtkSelectionModel *model,guint position,guint n_items,gboolean unselect_rest);
Requests to select a range of items in the model.
gtk_selection_model_unselect_range ()
gboolean gtk_selection_model_unselect_range (GtkSelectionModel *model,guint position,guint n_items);
Requests to unselect a range of items in the model.
gtk_selection_model_select_all ()
gboolean
gtk_selection_model_select_all (GtkSelectionModel *model);
Requests to select all items in the model.
gtk_selection_model_unselect_all ()
gboolean
gtk_selection_model_unselect_all (GtkSelectionModel *model);
Requests to unselect all items in the model.
gtk_selection_model_set_selection ()
gboolean gtk_selection_model_set_selection (GtkSelectionModel *model,GtkBitset *selected,GtkBitset *mask);
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:
1 2 3 4 5 6 7 8 9 10 11 12 13 |
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.
gtk_selection_model_selection_changed ()
void gtk_selection_model_selection_changed (GtkSelectionModel *model,guint position,guint n_items);
Helper function for implementations of GtkSelectionModel. Call this when a the selection changes to emit the “selection-changed” signal.
Signal Details
The “selection-changed” signal
void user_function (GtkSelectionModel *model, guint position, guint n_items, gpointer user_data)
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
model |
||
position |
The first item that may have changed |
|
n_items |
number of items with changes |
|
user_data |
user data set when the signal handler was connected. |
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