Graphics.UI.Gtk.ModelView.CustomStore

Allows a custom data structure to be used with the TreeView and other widgets that follow the model-view-controller paradigm. The two models ListStore and TreeStore are based on the CustomStore. Even if no application-specific tree model should be implemented, this module is relevant in that it provides the functions customStoreSetColumn and customStoreGetRow functions.

The definition of a row-based store.

data CustomStore private row

A CustomStore is an instance of a Gtk+ TreeModel and can thus be used for any widget that stores data in a TreeModel. The user may either create an instance of a CustomStore or use one of the pre-defined models ListStore of TreeStore.

Instances

GObjectClass (CustomStore private row)

TreeModelClass (CustomStore private row)

data TreeModelFlags

These flags indicate various properties of a TreeModel.

• If a model has TreeModelItersPersist set, iterators remain valid after a TreeModel signal was emitted.
• The TreeModelListOnly flag is set if the rows are arranged in a simple flat list. This is set in the ListStore implementation.

Constructors

TreeModelItersPersist

TreeModelListOnly

Instances

Bounded TreeModelFlags

Enum TreeModelFlags

Flags TreeModelFlags

data TreeModelIface row

The TreeModelIface structure contains all functions that are required to implement an application-specific TreeModel.

Constructors

TreeModelIface

Fields

treeModelIfaceGetFlags :: IO [TreeModelFlags]

Return the flags that are valid for this model.

treeModelIfaceGetIter :: TreePath -> IO (Maybe TreeIter)

Convert an path into the tree into a more concise TreeIter. Return Nothing if the path does not exit.

treeModelIfaceGetPath :: TreeIter -> IO TreePath

Convert an iterator to a path. The iterator will always be valid.

treeModelIfaceGetRow :: TreeIter -> IO row

Retrieve a row at the given iterator.

treeModelIfaceIterNext :: TreeIter -> IO (Maybe TreeIter)

Advance the given iterator to the next node at the same level. Return Nothing if there is no next node at this level.

treeModelIfaceIterChildren :: Maybe TreeIter -> IO (Maybe TreeIter)

Advance the given iterator to the first child of this iterator. Return Notihing if the node at this iterator has no children.

treeModelIfaceIterHasChild :: TreeIter -> IO Bool

Check if the node at the given iterator has children.

treeModelIfaceIterNChildren :: Maybe TreeIter -> IO Int

Query the number of children the the node at the given iteratore has.

treeModelIfaceIterNthChild :: Maybe TreeIter -> Int -> IO (Maybe TreeIter)

Ask for an iterator to the nth child. Return Nothing if no such child exists.

treeModelIfaceIterParent :: TreeIter -> IO (Maybe TreeIter)

Ask for an iterator to the parent of the node.

treeModelIfaceRefNode :: TreeIter -> IO ()

Increase a reference count for this node. A positive reference count indicates that the node is used (that is, most likely it is visible) in at least one widget. Tracking reference counts for nodes is optional but may be useful to infer when a given row can be discarded if it was retrieved from an external source.

treeModelIfaceUnrefNode :: TreeIter -> IO ()

Decrement the reference count of the given node.

data DragSourceIface model row

A structure containing functions that enable this widget to be used as a source in drag-and-drop.

Constructors

DragSourceIface

Fields

treeDragSourceRowDraggable :: model row -> TreePath -> IO Bool

Determine if the row at the given path is draggable. Return False if for some reason this row should not be dragged by the user.

treeDragSourceDragDataGet :: model row -> TreePath -> SelectionDataM Bool

Fill in the SelectionDataM structure with information on the given node using selectionDataSet.

treeDragSourceDragDataDelete :: model row -> TreePath -> IO Bool

The widget is informed that the row at the given path should be deleted as the result of this drag.

data DragDestIface model row

A structure containing functions that enable this widget to be used as a target in drag-and-drop.

Constructors

DragDestIface

Fields

treeDragDestRowDropPossible :: model row -> TreePath -> SelectionDataM Bool

Tell the drag-and-drop mechanism if the row can be dropped at the given path.

treeDragDestDragDataReceived :: model row -> TreePath -> SelectionDataM Bool

The data in the SelectionDataM structure should be read using selectionDataGet and its information be used to insert a new row at the given path.

customStoreNew

Arguments

:: (TreeModelClass (model row), TypedTreeModelClass model)

=> private

Any private data the store needs to store. Usually an IORef.

-> (CustomStore private row -> model row)

-> TreeModelIface row

Functions necessary to implement the TreeModel interface.

-> Maybe (DragSourceIface model row)

Functions to enable this store to generate drag events.

-> Maybe (DragDestIface model row)

Functions to enable this store to receive drag events.

-> IO (model row)

Create a new store that implements the TreeModelIface interface and optionally the DragSourceIface and the DragDestIface. If the latter two are set to Nothing a dummy interface is substituted that rejects every drag and drop.

customStoreGetRow :: TypedTreeModelClass model => model row -> TreeIter -> IO row

Extract a row of the given model at the given TreeIter.

customStoreSetColumn

Arguments

:: TypedTreeModelClass model

=> model row

the store in which to allocate a new column

-> ColumnId row ty

the column that should be set

-> (row -> ty)

the function that sets the property

-> IO ()

Set or update a column mapping. This function should be used before the model is installed into a widget since the number of defined columns are only checked once by widgets.

customStoreGetPrivate :: CustomStore private row -> private

Return the private data stored in this CustomStore. The private data is meant as a container for the data stored in this model.

customStoreGetStamp :: CustomStore private row -> IO CInt

Query the current value of the stamp that is used to create TreeIter iterators. The stamp is compared each time a view accesses this store. If the stamp doesn't match, a warning is emitted. The stamp should be updated each time a the data in the model changes. The rationale is that a view should never use a stale TreeIter, i.e., one that refers to an old model.

customStoreInvalidateIters :: CustomStore private row -> IO ()

Create a new stamp. See customStoreGetStamp.

treeModelGetRow :: TypedTreeModelClass model => model row -> TreeIter -> IO row

treeModelSetColumn

Arguments

:: TypedTreeModelClass model

=> model row

the store in which to allocate a new column

-> ColumnId row ty

the column that should be set

-> (row -> ty)

the function that sets the property

-> IO ()