GtkTreeModel              package:RGtk2              R Documentation

_G_t_k_T_r_e_e_M_o_d_e_l

_D_e_s_c_r_i_p_t_i_o_n:

     The tree interface used by GtkTreeView

_M_e_t_h_o_d_s _a_n_d _F_u_n_c_t_i_o_n_s:

     'gtkTreePathNew()'
      'gtkTreePathNewFromString(path)'
      'gtkTreePathNewFromIndices(...)'
      'gtkTreePathToString(object)'
      'gtkTreePathNewFirst()'
      'gtkTreePathAppendIndex(object, index)'
      'gtkTreePathPrependIndex(object, index)'
      'gtkTreePathGetDepth(object)'
      'gtkTreePathGetIndices(object)'
      'gtkTreePathCopy(object)'
      'gtkTreePathCompare(object, b)'
      'gtkTreePathNext(object)'
      'gtkTreePathPrev(object)'
      'gtkTreePathUp(object)'
      'gtkTreePathDown(object)'
      'gtkTreePathIsAncestor(object, descendant)'
      'gtkTreePathIsDescendant(object, ancestor)'
      'gtkTreeRowReferenceNew(model, path)'
      'gtkTreeRowReferenceNewProxy(proxy, model, path)'
      'gtkTreeRowReferenceGetModel(object)'
      'gtkTreeRowReferenceGetPath(object)'
      'gtkTreeRowReferenceValid(object)'
      'gtkTreeRowReferenceCopy(object)'
      'gtkTreeRowReferenceInserted(proxy, path)'
      'gtkTreeRowReferenceDeleted(proxy, path)'
      'gtkTreeRowReferenceReordered(proxy, path, iter, new.order)'
      'gtkTreeIterCopy(object)'
      'gtkTreeModelGetFlags(object)'
      'gtkTreeModelGetNColumns(object)'
      'gtkTreeModelGetColumnType(object, index)'
      'gtkTreeModelGetIter(object, path)'
      'gtkTreeModelGetIterFromString(object, path.string)'
      'gtkTreeModelGetIterFirst(object)'
      'gtkTreeModelGetPath(object, iter)'
      'gtkTreeModelGetValue(object, iter, column)'
      'gtkTreeModelIterNext(object, iter)'
      'gtkTreeModelIterChildren(object, parent = NULL)'
      'gtkTreeModelIterHasChild(object, iter)'
      'gtkTreeModelIterNChildren(object, iter = NULL)'
      'gtkTreeModelIterNthChild(object, parent = NULL, n)'
      'gtkTreeModelIterParent(object, child)'
      'gtkTreeModelGetStringFromIter(object, iter)'
      'gtkTreeModelRefNode(object, iter)'
      'gtkTreeModelUnrefNode(object, iter)'
      'gtkTreeModelGet(object, iter, ...)'
      'gtkTreeModelForeach(object, func, user.data = NULL)'
      'gtkTreeModelRowChanged(object, path, iter)'
      'gtkTreeModelRowInserted(object, path, iter)'
      'gtkTreeModelRowHasChildToggled(object, path, iter)'
      'gtkTreeModelRowDeleted(object, path)'
      'gtkTreeModelRowsReordered(object, path, iter, new.order)'

_H_i_e_r_a_r_c_h_y:

     GInterface
        +----GtkTreeModel 

_I_m_p_l_e_m_e_n_t_a_t_i_o_n_s:

     GtkTreeModel is implemented by 'GtkTreeModelFilter', 
     'GtkTreeModelSort',  'GtkTreeStore' and  'GtkListStore'.

_I_n_t_e_r_f_a_c_e _D_e_r_i_v_a_t_i_o_n_s:

     GtkTreeModel is required by 'GtkTreeSortable'.

_D_e_t_a_i_l_e_d _D_e_s_c_r_i_p_t_i_o_n:

     The 'GtkTreeModel' interface defines a generic tree interface for
     use by the 'GtkTreeView' widget.  It is an abstract interface, and
     is designed to be usable with any appropriate data structure.  The
     programmer just has to implement this interface on their own data
     type for it to be viewable by a 'GtkTreeView' widget.

     The model is represented as a hierarchical tree of strongly-typed,
     columned data.  In other words, the model can be seen as a tree
     where every node has different values depending on which column is
     being queried.  The type of data found in a column is determined
     by using the GType system (ie. 'G_TYPE_INT', 'GTK_TYPE_BUTTON',
     'G_TYPE_POINTER', etc.). The types are homogeneous per column
     across all nodes.  It is important to note that this interface
     only provides a way of examining a model and observing changes. 
     The implementation of each individual model decides how and if
     changes are made.

     In order to make life simpler for programmers who do not need to
     write their own specialized model, two generic models are provided
     - the 'GtkTreeStore' and the 'GtkListStore'.  To use these, the
     developer simply pushes data into these models as necessary. 
     These models provide the data structure as well as all appropriate
     tree interfaces.  As a result, implementing drag and drop,
     sorting, and storing data is trivial.  For the vast majority of
     trees and lists, these two models are sufficient.

     Models are accessed on a node/column level of granularity.  One
     can query for the value of a model at a certain node and a certain
     column on that node.  There are two structures used to reference a
     particular node in a model.  They are the 'GtkTreePath' and the
     'GtkTreeIter' *PLEASE NOTE:* Here, _iter_ is short for "iterator"
     Most of the interface consists of operations on a 'GtkTreeIter'.

     A path is essentially a potential node.  It is a location on a
     model that may or may not actually correspond to a node on a
     specific model. The 'GtkTreePath' struct can be converted into
     either a list of unsigned integers or a string.  The string form
     is a list of numbers separated by a colon.  Each number refers to
     the offset at that level. Thus, the path "0" refers to the root
     node and the path "2:4" refers to the fifth child of the third
     node.

     By contrast, a 'GtkTreeIter' is a reference to a specific node on
     a specific model.  It is a generic struct with an integer and
     three generic pointers.  These are filled in by the model in a
     model-specific way.  One can convert a path to an iterator by
     calling 'gtkTreeModelGetIter'.  These iterators are the primary
     way of accessing a model and are similar to the iterators used by
     'GtkTextBuffer'.  They are generally statically allocated on the
     stack and only used for a short time.  The model interface defines
     a set of operations using them for navigating the model.

     It is expected that models fill in the iterator with private data.
      For example, the 'GtkListStore' model, which is internally a
     simple linked list, stores a list node in one of the pointers. 
     The 'GtkTreeModelSort' stores a list and an offset in two of the
     pointers.  Additionally, there is an integer field.  This field is
     generally filled with a unique stamp per model.  This stamp is for
     catching errors resulting from using invalid iterators with a
     model.

     The lifecycle of an iterator can be a little confusing at first.
     Iterators are expected to always be valid for as long as the model
     is unchanged (and doesn't emit a signal).  The model is considered
     to own all outstanding iterators and nothing needs to be done to
     free them from the user's point of view.  Additionally, some
     models guarantee that an iterator is valid for as long as the node
     it refers to is valid (most notably the 'GtkTreeStore' and
     'GtkListStore').  Although generally uninteresting, as one always
     has to allow for the case where iterators do not persist beyond a
     signal, some very important performance enhancements were made in
     the sort model.  As a result, the 'GTK_TREE_MODEL_ITERS_PERSIST'
     flag was added to indicate this behavior.

     To help show some common operation of a model, some examples are
     provided.  The first example shows three ways of getting the iter
     at the location "3:2:5".  While the first method shown is easier,
     the second is much more common, as you often get paths from
     callbacks.

     _Acquiring a   'GtkTreeIter'_


     ## Acquiring a GtkTreeIter

     ## Three ways of getting the iter pointing to the location

     ## get the iterator from a string 
     model$getIterFromString("3:2:5")$iter

     ## get the iterator from a path
     path <- gtkTreePathNewFromString("3:2:5")
     model$getIter(path)$iter

     ## walk the tree to find the iterator
     parent_iter <- model$iterNthChild(NULL, 3)$iter
     parent_iter <- model$iterNthChild(parent_iter, 2)$iter
     model$iterNthChild(parent_iter, 5)$iter
      This second example shows a quick way of iterating through a list
     and getting a string and an integer from each row.  The
     'populateModel' function used below is not shown, as it is
     specific to the 'GtkListStore'.  For information on how to write
     such a function, see the 'GtkListStore' documentation.

     _Reading data from a   'GtkTreeModel'_


     ## Reading data from a GtkTreeModel

     ## make a new list_store
     list_store <- gtkListStore("character", "integer")

     ## Fill the list store with data
     populate_model(list_store)

     ## Get the first iter in the list 
     result <- list_store$getIterFirst()

     row_count <- 1
     while(result[[1]]) {
       ## Walk through the list, reading each row

       data <- list_store$get(result$iter, 0, 1)

       ## Do something with the data
       print(paste("Row ", row_count, ": (", data[[1]], ",", data[[2]],
     ")", sep=""))

       row_count <- row_count + 1
       result <- list_store$iterNext()
     }


_S_t_r_u_c_t_u_r_e_s:


     '_G_t_k_T_r_e_e_M_o_d_e_l' _undocumented _


     '_G_t_k_T_r_e_e_I_t_e_r' The 'GtkTreeIter' is the primary structure for
          accessing a structure.  Models are expected to put a unique
          integer in the 'stamp' member, and put model-specific data in
          the three 'user_data' members.

          '_s_t_a_m_p' [integer] A unique stamp to catch invalid iterators

          '_u_s_e_r__d_a_t_a' [R object] Model specific data

          '_u_s_e_r__d_a_t_a_2' [R object] Model specific data

          '_u_s_e_r__d_a_t_a_3' [R object] Model specific data


     '_G_t_k_T_r_e_e_P_a_t_h' _undocumented _


     '_G_t_k_T_r_e_e_R_o_w_R_e_f_e_r_e_n_c_e' _undocumented _


_E_n_u_m_s _a_n_d _F_l_a_g_s:


     '_G_t_k_T_r_e_e_M_o_d_e_l_F_l_a_g_s' These flags indicate various properties of a
          'GtkTreeModel'.  They are returned by 'gtkTreeModelGetFlags',
          and must be static for the lifetime of the object.  A more
          complete description of 'GTK_TREE_MODEL_ITERS_PERSIST' can be
          found in the overview of this section.

          '_i_t_e_r_s-_p_e_r_s_i_s_t' Iterators survive all signals emitted by the
               tree.

          '_l_i_s_t-_o_n_l_y' The model is a list only, and never has children


_U_s_e_r _F_u_n_c_t_i_o_n_s:


     '_G_t_k_T_r_e_e_M_o_d_e_l_F_o_r_e_a_c_h_F_u_n_c(_m_o_d_e_l, _p_a_t_h, _i_t_e_r, _d_a_t_a)' _undocumented _

          '_m_o_d_e_l' ['GtkTreeModel'] The 'GtkTreeModel' currently being
               iterated

          '_p_a_t_h' ['GtkTreePath'] The current 'GtkTreePath'

          '_i_t_e_r' ['GtkTreeIter'] The current 'GtkTreeIter'

          '_d_a_t_a' [R object] The user data passed to
               'gtkTreeModelForeach'

          _Returns:_ [logical] 'TRUE' to stop iterating, 'FALSE' to
          continue.


_S_i_g_n_a_l_s:


     '_r_o_w-_c_h_a_n_g_e_d(_t_r_e_e._m_o_d_e_l, _p_a_t_h, _i_t_e_r, _u_s_e_r._d_a_t_a)' This signal is
          emitted when a row in the model has changed.  

          '_t_r_e_e._m_o_d_e_l' ['GtkTreeModel']  the 'GtkTreeModel' on which
               the signal is emitted

          '_p_a_t_h' ['GtkTreePath']  a 'GtkTreePath' identifying the
               changed row

          '_i_t_e_r' ['GtkTreeIter']  a valid 'GtkTreeIter' pointing to the
               changed row

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


     '_r_o_w-_d_e_l_e_t_e_d(_t_r_e_e._m_o_d_e_l, _p_a_t_h, _u_s_e_r._d_a_t_a)' This signal is emitted
          when a row has been deleted.

          Note that no iterator is passed to the signal handler, since
          the row is already deleted.

          Implementations of GtkTreeModel must emit row-deleted 
          _before_ removing the node from its internal data structures.
           This is because models and  views which access and monitor
          this model might have references on the node which need to be
          released in the row-deleted handler.  

          '_t_r_e_e._m_o_d_e_l' ['GtkTreeModel']  the 'GtkTreeModel' on which
               the signal is emitted

          '_p_a_t_h' ['GtkTreePath']  a 'GtkTreePath' identifying the row

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


     '_r_o_w-_h_a_s-_c_h_i_l_d-_t_o_g_g_l_e_d(_t_r_e_e._m_o_d_e_l, _p_a_t_h, _i_t_e_r, _u_s_e_r._d_a_t_a)' This
          signal is emitted when a row has gotten the first child row
          or lost its last child row.  

          '_t_r_e_e._m_o_d_e_l' ['GtkTreeModel']  the 'GtkTreeModel' on which
               the signal is emitted

          '_p_a_t_h' ['GtkTreePath']  a 'GtkTreePath' identifying the row

          '_i_t_e_r' ['GtkTreeIter']  a valid 'GtkTreeIter' pointing to the
               row

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


     '_r_o_w-_i_n_s_e_r_t_e_d(_t_r_e_e._m_o_d_e_l, _p_a_t_h, _i_t_e_r, _u_s_e_r._d_a_t_a)' This signal is
          emitted when a new row has been inserted in the model.

          Note that the row may still be empty at this point, since it
          is a common pattern to first insert an empty row, and  then
          fill it with the desired values.  

          '_t_r_e_e._m_o_d_e_l' ['GtkTreeModel']  the 'GtkTreeModel' on which
               the signal is emitted

          '_p_a_t_h' ['GtkTreePath']  a 'GtkTreePath' identifying the new
               row

          '_i_t_e_r' ['GtkTreeIter']  a valid 'GtkTreeIter' pointing to the
               new row

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


     '_r_o_w_s-_r_e_o_r_d_e_r_e_d(_t_r_e_e._m_o_d_e_l, _p_a_t_h, _i_t_e_r, _u_s_e_r._d_a_t_a)' This signal is
          emitted when the children of a node in the 'GtkTreeModel'
          have been reordered. 

          Note that this signal is _not_ emitted when rows are
          reordered by DND, since this is implemented by removing and
          then reinserting the row.  

          '_t_r_e_e._m_o_d_e_l' ['GtkTreeModel']  the 'GtkTreeModel' on which
               the signal is emitted

          '_p_a_t_h' ['GtkTreePath']  a 'GtkTreePath' identifying the tree
               node whose children have been reordered

          '_i_t_e_r' ['GtkTreeIter']  a valid 'GtkTreeIter' pointing to the
               node whose 

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


_A_u_t_h_o_r(_s):

     Derived by RGtkGen from GTK+ documentation

_R_e_f_e_r_e_n_c_e_s:

     <URL:
     http://developer.gnome.org/doc/API/2.0/gtk/GtkTreeModel.html>

_S_e_e _A_l_s_o:

     'GtkTreeView' 'GtkTreeStore' 'GtkListStore' 'GtkTreeSortable'

