asp.net ean 128 THE TREE VIEW WIDGET in Font

Encoder Data Matrix 2d barcode in Font THE TREE VIEW WIDGET

GtkCellRendererSpin is compatible with both integers and floating point numbers, because its parameters are stored in a GtkAdjustment. Listing 8-14 is an implementation of the Grocery List application in which the Quantity column is rendered with GtkCellRendererSpin. Listing 8-14. Spin Button Cell Renderers static void setup_tree_view (GtkWidget *treeview) { GtkCellRenderer *renderer; GtkTreeViewColumn *column; GtkAdjustment *adj; adj = GTK_ADJUSTMENT (gtk_adjustment_new (0.0, 0.0, 100.0, 1.0, 2.0, 2.0)); renderer = gtk_cell_renderer_spin_new (); g_object_set (renderer, "editable", TRUE, "adjustment", adj, "digits", 0, NULL); g_signal_connect (G_OBJECT (renderer), "edited", G_CALLBACK (cell_edited), (gpointer) treeview); column = gtk_tree_view_column_new_with_attributes ("Count", renderer, "text", QUANTITY, NULL); gtk_tree_view_append_column (GTK_TREE_VIEW (treeview), column); /* ... Add a cell renderer for the PRODUCT column ... */ } /* Apply the changed text to the cell. */ static void cell_edited (GtkCellRendererText *renderer, gchar *path, gchar *new_text, GtkTreeView *treeview) { GtkTreeIter iter; GtkTreeModel *model; GtkAdjustment *adjustment; gdouble value; /* Retrieve the current value stored by the spin button renderer's adjustment. */ g_object_get (renderer, "adjustment", &adjustment, NULL); value = gtk_adjustmnet_get_value (adjustment);

model = gtk_tree_view_get_model (treeview); if (gtk_tree_model_get_iter_from_string (model, &iter, path)) gtk_list_store_set (GTK_LIST_STORE (model), &iter, QUANTITY, value, -1); } New GtkCellRendererSpin objects are created with gtk_cell_renderer_spin(). After you create the renderer, you should set the editable, adjustment, and digits properties of the object with g_object_set(). g_object_set (renderer, "editable", TRUE, "adjustment", adj, "digits", 0, NULL); GtkCellRendererSpin provides three properties: adjustment, climb-rate, and digits. These are stored in a GtkAdjustment defining the spin button s properties, the acceleration rate when an arrow button is held down, and the number of decimal places to display in the spin button respectively. The climb rate and number of decimals to display are both set to zero by default. GtkCellRendererSpin is derived from GtkCellRendererText, so you also have all of GtkCellRendererText s properties available, including editable, which must be set to TRUE to allow the content of the cell to be edited. After setting up the cell renderer, you should then connect to the edited signal to the cell renderer, which will be used to apply the new value chosen by the user to the cell. There is usually no need to filter this value, because the adjustment will already limit the values allowed by the cell. The callback function will be run after the user presses the Enter key or moves focus from the spin button of a cell that is being edited. Within the cell_edited() callback function in Listing 8-14, you need to first retrieve the adjustment of the spin button renderer, because it will store the new value that is to be displayed. This new value can then be applied to the given cell.

Note Although the edited signal of a GtkCellRendererText still receives the new_text parameter, this should not be used. The parameter will not store a textual version of the spin button s value. Furthermore, the value used in gtk_list_store_set() that will replace the current value must be supplied as a floating point number, so a string will not be acceptable regardless of its contents.

You can retrieve the adjustment s value with gtk_adjustment_get_value(), applying it to the appropriate column. Since the QUANTITY column is used to display a floating point number (G_TYPE_FLOAT), you can use the returned type in its current state. When creating the tree model, the column must be of the type G_TYPE_FLOAT, even if you want to store an integer. You should use cell data functions to limit the number of decimal places displayed by each cell.

GtkCellRendererCombo provides a cell renderer for a widget that you have just learned about, GtkComboBox. Combo box cell renderers are useful, because they allow you to present multiple predefined options to the user. GtkCellRendererCombo renders text in a similar way to