### Tutorial
« Creating the View Component | Text Widget »

## A Simple Example

Here is a simple example of using a TreeView widget in context of the other widgets. It simply creates a simple model and view, and puts them together. The model is populated with the data from the section: "Creating a Model". More information can be found on this in The TreeModel Interface section.
The header file for TreeView Example is treeview.h:

`#include<inti/main.h> #include <inti/gtk/window.h> #include <inti/gtk/treestore.h> #include <inti/gtk/treeview.h> using namespace Inti; class TreeViewWindow : public Gtk::Window { Pointer<Gtk::TreeStore> model; Gtk::TreeView *tree_view; protected: void on_selection(); void on_toggled(const char *path_str); public: TreeViewWindow(); virtual ~TreeViewWindow(); };`

and the source file is treeview.cc:

`#include"treeview.h" #include <inti/gtk/cellrenderer.h> #include <iostream> enum { TITLE_COLUMN, AUTHOR_COLUMN, CHECKED_COLUMN, N_COLUMNS }; TreeViewWindow::TreeViewWindow() { set_title("TreeView Example"); // We'll create a TreeStore model but this could be any model. The model pointer // is a smart pointer because we own the initial reference and it must be freed. model = new Gtk::TreeStore(N_COLUMNS, G_TYPE_STRING, G_TYPE_STRING, G_TYPE_BOOLEAN); // Populate the model with data. First acquire a top-level iterator. Gtk::TreeIter parent_iter = model->append(); // Then, set the cell values model->set_value(parent_iter, TITLE_COLUMN, "The Art of Computer Programming"); model->set_value(parent_iter, AUTHOR_COLUMN, "Donald E. Knuth"); model->set_value(parent_iter, CHECKED_COLUMN, false); // Then, acquire a child iterator and set the values for the child cells Gtk::TreeIter child_iter = model->append(&parent_iter); model->set_value(child_iter, TITLE_COLUMN, "Volume 1: Fundamental Algorithms"); model->set_value(child_iter, CHECKED_COLUMN, false); child_iter = model->append(&parent_iter); model->set_value(child_iter, TITLE_COLUMN, "Volume 2: Seminumerical Algorithms"); model->set_value(child_iter, CHECKED_COLUMN, false); child_iter = model->append(&parent_iter); model->set_value(child_iter, TITLE_COLUMN, "Volume 3: Sorting and Searching"); model->set_value(child_iter, CHECKED_COLUMN, false); // Create a TreeView tree_view = new Gtk::TreeView(*model); // You can't create a TreeSelection, you have to retrieve it from the TreeView. Gtk::TreeSelection *selection = tree_view->get_selection(); selection->set_mode (Gtk::SELECTION_SINGLE); selection->sig_changed().connect(slot(this, &TreeViewWindow::on_selection)); // Create a text cell render and arbitrarily make it red for demonstration purposes. Gtk::CellRendererText *renderer = new Gtk::CellRendererText; renderer->prop_foreground().set("red"); // Create first column, associating the "text" attribute of the cell_renderer with the first column of the model Gtk::TreeViewColumn *column = new Gtk::TreeViewColumn("Author", renderer, "text", AUTHOR_COLUMN, 0); // Add the column to the view. tree_view->append_column(*column); // Create second column. The title of the book. renderer = new Gtk::CellRendererText; column = new Gtk::TreeViewColumn("Title", renderer, "text", TITLE_COLUMN, 0); tree_view->append_column(*column); // Create last column. Whether a book is checked out. Gtk::CellRendererToggle *toggle_renderer = new Gtk::CellRendererToggle; toggle_renderer->sig_toggled().connect(slot(this, &TreeViewWindow::on_toggled)); column = new Gtk::TreeViewColumn("Check out", toggle_renderer, "active", CHECKED_COLUMN, 0); tree_view->append_column(*column); // Now we can manipulate the view just like any other widget add(*tree_view); tree_view->show_all(); } TreeViewWindow::~TreeViewWindow() { } void TreeViewWindow::on_selection() { Gtk::TreeIter iter; Gtk::TreeSelection *selection = tree_view->get_selection(); if (selection->get_selected(&iter)) { String title; model->get_value(iter, TITLE_COLUMN, title); std::cout << "You selected a book with the title \"" << title << "\"" << std::endl; } } void TreeViewWindow::on_toggled(const char *path_str) { Gtk::TreeIter iter; Pointer<Gtk::TreePath> path = new Gtk::TreePath(path_str); // Get toggled iter model->get_iter(iter, *path); bool checked; model->get_value(iter, CHECKED_COLUMN, checked); // Do something with the value checked ^= 1; // Set new value for the CHECKED_COLUMN model->set_value(iter, CHECKED_COLUMN, checked); } int main (int argc, char *argv[]) { using namespace Main; init(&argc, &argv); TreeViewWindow window; window.sig_destroy().connect(slot(&Inti::Main::quit)); window.show(); run(); return 0; }`

« Creating the View Component | Index Tree and List Widget Top | Text Widget »