Interface CellLayout

All Superinterfaces:
Proxy
All Known Implementing Classes:
CellArea, CellArea.CellArea$Impl, CellAreaBox, CellLayout.CellLayout$Impl, CellView, ComboBox, ComboBoxText, EntryCompletion, IconView, TreeViewColumn
@Generated("org.javagi.JavaGI") @Deprecated public interface CellLayout extends Proxy
Deprecated.
List views use widgets to display their contents. See LayoutManager for layout manager delegate objects

An interface for packing cells

GtkCellLayout is an interface to be implemented by all objects which want to provide a GtkTreeViewColumn like API for packing cells, setting attributes and data funcs.

One of the notable features provided by implementations of GtkCellLayout are attributes. Attributes let you set the properties in flexible ways. They can just be set to constant values like regular properties. But they can also be mapped to a column of the underlying tree model with gtk_cell_layout_set_attributes(), which means that the value of the attribute can change from cell to cell as they are rendered by the cell renderer. Finally, it is possible to specify a function with gtk_cell_layout_set_cell_data_func() that is called to determine the value of the attribute for each cell that is rendered.

GtkCellLayouts as GtkBuildable

Implementations of GtkCellLayout which also implement the GtkBuildable interface (GtkCellView, GtkIconView, GtkComboBox, GtkEntryCompletion, GtkTreeViewColumn) accept GtkCellRenderer objects as <child> elements in UI definitions. They support a custom <attributes> element for their children, which can contain multiple <attribute> elements. Each <attribute> element has a name attribute which specifies a property of the cell renderer; the content of the element is the attribute value.

This is an example of a UI definition fragment specifying attributes:

<object class="GtkCellView">
  <child>
    <object class="GtkCellRendererText"/>
    <attributes>
      <attribute name="text">0</attribute>
    </attributes>
  </child>
</object>

Furthermore for implementations of GtkCellLayout that use a GtkCellArea to lay out cells (all GtkCellLayouts in GTK use a GtkCellArea) cell properties can also be defined in the format by specifying the custom <cell-packing> attribute which can contain multiple <property> elements.

Here is a UI definition fragment specifying cell properties:

<object class="GtkTreeViewColumn">
  <child>
    <object class="GtkCellRendererText"/>
    <cell-packing>
      <property name="align">True</property>
      <property name="expand">False</property>
    </cell-packing>
  </child>
</object>

Subclassing GtkCellLayout implementations

When subclassing a widget that implements GtkCellLayout like GtkIconView or GtkComboBox, there are some considerations related to the fact that these widgets internally use a GtkCellArea. The cell area is exposed as a construct-only property by these widgets. This means that it is possible to e.g. do

GtkWIdget *combo =
  g_object_new (GTK_TYPE_COMBO_BOX, "cell-area", my_cell_area, NULL);

to use a custom cell area with a combo box. But construct properties are only initialized after instance init() functions have run, which means that using functions which rely on the existence of the cell area in your subclass init() function will cause the default cell area to be instantiated. In this case, a provided construct property value will be ignored (with a warning, to alert you to the problem).

static void
my_combo_box_init (MyComboBox *b)
{
  GtkCellRenderer *cell;

  cell = gtk_cell_renderer_pixbuf_new ();

  // The following call causes the default cell area for combo boxes,
  // a GtkCellAreaBox, to be instantiated
  gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (b), cell, FALSE);
  ...
}

GtkWidget *
my_combo_box_new (GtkCellArea *area)
{
  // This call is going to cause a warning about area being ignored
  return g_object_new (MY_TYPE_COMBO_BOX, "cell-area", area, NULL);
}

If supporting alternative cell areas with your derived widget is not important, then this does not have to concern you. If you want to support alternative cell areas, you can do so by moving the problematic calls out of init() and into a constructor() for your class.

  • Method Details

    • getType

      static @Nullable Type getType()
      Deprecated.
      Get the GType of the CellLayout class.
      Returns:
      the GType

    • addAttribute

      @Deprecated default void addAttribute(CellRenderer cell, String attribute, int column)
      Deprecated.

      Adds an attribute mapping to the list in cellLayout.

      The column is the column of the model to get a value from, and the attribute is the property on cell to be set from that value. So for example if column 2 of the model contains strings, you could have the “text” attribute of a GtkCellRendererText get its values from column 2. In this context "attribute" and "property" are used interchangeably.

      Parameters:
      cell - a GtkCellRenderer
      attribute - a property on the renderer
      column - the column position on the model to get the attribute from

    • clear

      @Deprecated default void clear()
      Deprecated.
      Unsets all the mappings on all renderers on this CellLayout and removes all renderers from cellLayout.

    • clearAttributes

      @Deprecated default void clearAttributes(CellRenderer cell)
      Deprecated.
      Clears all existing attributes previously set with gtk_cell_layout_set_attributes().
      Parameters:
      cell - a GtkCellRenderer to clear the attribute mapping on

    • getArea

      @Deprecated default @Nullable CellArea getArea()
      Deprecated.
      Returns the underlying GtkCellArea which might be this CellLayout if called on a GtkCellArea or might be null if no GtkCellArea is used by cellLayout.
      Returns:
      the cell area used by this CellLayout

    • getCells

      @Deprecated default List<CellRenderer> getCells()
      Deprecated.
      Returns the cell renderers which have been added to cellLayout.
      Returns:
      a list of cell renderers. The list, but not the renderers has been newly allocated and should be freed with g_list_free() when no longer needed.

    • packEnd

      @Deprecated default void packEnd(CellRenderer cell, boolean expand)
      Deprecated.

      Adds the cell to the end of cellLayout. If expand is false, then the cell is allocated no more space than it needs. Any unused space is divided evenly between cells for which expand is true.

      Note that reusing the same cell renderer is not supported.

      Parameters:
      cell - a GtkCellRenderer
      expand - true if cell is to be given extra space allocated to this CellLayout

    • packStart

      @Deprecated default void packStart(CellRenderer cell, boolean expand)
      Deprecated.

      Packs the cell into the beginning of cellLayout. If expand is false, then the cell is allocated no more space than it needs. Any unused space is divided evenly between cells for which expand is true.

      Note that reusing the same cell renderer is not supported.

      Parameters:
      cell - a GtkCellRenderer
      expand - true if cell is to be given extra space allocated to this CellLayout

    • reorder

      @Deprecated default void reorder(CellRenderer cell, int position)
      Deprecated.

      Re-inserts cell at position.

      Note that cell has already to be packed into this CellLayout for this to function properly.

      Parameters:
      cell - a GtkCellRenderer to reorder
      position - new position to insert cell at

    • setAttributes

      @Deprecated default void setAttributes(CellRenderer cell, Object... varargs)
      Deprecated.

      Sets the attributes in the parameter list as the attributes of cellLayout.

      See addAttribute(CellRenderer, String, int) for more details.

      The attributes should be in attribute/column order, as in gtk_cell_layout_add_attribute(). All existing attributes are removed, and replaced with the new attributes.

      Parameters:
      cell - a GtkCellRenderer
      varargs - a null-terminated list of attributes

    • setCellDataFunc

      @Deprecated default void setCellDataFunc(CellRenderer cell, @Nullable CellLayoutDataFunc func)
      Deprecated.

      Sets the GtkCellLayoutDataFunc to use for cellLayout.

      This function is used instead of the standard attributes mapping for setting the column value, and should set the value of cellLayout’s cell renderer(s) as appropriate.

      func may be null to remove a previously set function.

      Parameters:
      cell - a GtkCellRenderer
      func - the GtkCellLayoutDataFunc to use