305. How to remove nodes from GtkTreeView - Part 1?

Problem

This is in response to Fernando's post titled 'Remove the nodes of a tree'.

He has set up a directory of files using GtkTreeView and he would like to remove all children of a node when he presses the Delete key on a node as shown below:

How to remove nodes from GtkTreeView - Part 1?


Solution

Note: The above make use of the GtkTreeModel functionality implemented by Andrei Zmievski. Please refer to his article New GtkTreeModel functionality.


Sample Code

Note 1: If you select "C:\", the program will run, but it will take a long time. You will see the processing, though, in the command window.

Note 2: On windows, you may see a warning "Gtk-WARNING: Could not find the icon 'stock_unknown'. The 'hicolor' theme was not found either, perhaps you need to install it." This is from the GtkFileChooserButton. It's just a warning. You may ignore it, or go ahead and install it.

Note 3: The following image files are required by the sample code below. Please save a copy of the image files and put them in the same directory where you store the sample code.

 folder_open.gif
 folder_closed.gif

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<?php
$window = new GtkWindow();
$window->connect_simple('destroy', array('Gtk','main_quit'));
$window->add($vbox = new GtkVBox());

// display title
$title = new GtkLabel("Remove nodes from GtkTreeView - Part 1");
$title->modify_font(new PangoFontDescription("Times New Roman Italic 10"));
$title->modify_fg(Gtk::STATE_NORMAL, GdkColor::parse("#0000ff"));
$title->set_size_request(-1, 40);
$vbox->pack_start($title, 0, 0);

$vbox->pack_start($vbox2 = new GtkVBox(), 0, 0);
$vbox2->set_size_request(-1, 40);
$vbox2->pack_start(new GtkLabel("Highlight a row, and press ".
"'Delete' key to delete a file/folder"), 0);
$vbox2->pack_start(new GtkLabel("This is a demo. It won't ".
"actually delete the file/folder"), 0);

$vbox->pack_start($hbox = new GtkHBox());
$hbox->pack_start(new GtkLabel('Click to select a folder: '), 0, 0);

// set up model
if (defined("GObject::TYPE_STRING")) {
    $model = new GtkTreeStore(GObject::TYPE_STRING);
} else {
    $model = new GtkTreeStore(Gtk::TYPE_STRING);
}

// set up file chooser button
$file_chooser_button = new GtkFileChooserButton('Select the Folder',
    Gtk::FILE_CHOOSER_ACTION_SELECT_FOLDER);
$file_chooser_button->set_size_request(320, -1);
$file_chooser_button->connect('selection-changed', 'on_selection_changed');
on_selection_changed($file_chooser_button);
$hbox->pack_start($file_chooser_button, 0, 0);

// set up scroll window
$scrolled_win = new GtkScrolledWindow();
$scrolled_win->set_policy( Gtk::POLICY_AUTOMATIC,
    Gtk::POLICY_AUTOMATIC);
$vbox->pack_start($scrolled_win);

// set up treeview
$view = new GtkTreeView($model);
$scrolled_win->add($view);
$view->set_size_request(400, 320);

//set up treeview columns
$column = new GtkTreeViewColumn();

// for image
$cell_renderer = new GtkCellRendererPixbuf();
$column->pack_start($cell_renderer, false);
$cell_renderer->set_property('pixbuf-expander-open',
    GdkPixbuf::new_from_file('folder_open.gif'));
$cell_renderer->set_property('pixbuf-expander-closed',
    GdkPixbuf::new_from_file('folder_closed.gif'));

// for filename
$cell_renderer = new GtkCellRendererText();
$column->pack_start($cell_renderer, true);
$column->set_attributes($cell_renderer, 'text', 0);

$view->append_column($column);
$column->set_title('Folders / Files');

$view->connect('key-press-event', 'on_keypress'); // note 1

//display it
$window->show_all();
Gtk::main();

function on_selection_changed($button) {
    $folder = $button->get_current_folder();
    echo "folder: $folder\n";
    populate_tree($folder);
}

function populate_tree($folder) {
    global $model;
    $model->clear();
    $root = $folder;
    $dir_list = array($root);
    $nodes = array();
    $nodes[$root] = null;
    while(count($dir_list)>0) {
        $dir = array_shift($dir_list);
        echo "folder = $dir\n";

        // add the directories first
        if ($handle = opendir($dir)) {
            while (false !== ($file = readdir($handle))) {
                if ($file != "." && $file != "..") {
                    $fullpath = $dir.'/'.$file;
                    if (is_dir($fullpath)) {
                        $nodes[$fullpath] = $model->append($nodes[$dir],
                            array($file));
                        array_push($dir_list, $fullpath);
                    }
                }
            }
            closedir($handle);
        }

        $num_files = 0;
        // then add the files
        if ($handle = opendir($dir)) {
            while (false !== ($file = readdir($handle))) {
                if ($file != "." && $file != "..") {
                    $fullpath = $dir.'/'.$file;
                    if (!is_dir($fullpath)) {
                        $nodes[$fullpath] = $model->append($nodes[$dir],
                            array($file));
                        ++$num_files;
                    }
                }
            }
            closedir($handle);
        }

        if ($num_files==0) $nodes[$fullpath] = $model->append($nodes[$dir],
            array(''));
    }
}

function on_keypress($widget, $event) {
    if ($event->keyval==Gdk::KEY_Delete) { // note 2
        global $view;
        $selection = $view->get_selection(); // note 3
        list($model, $iter) = $selection->get_selected(); // note 4
        if ($iter==NULL) return true; // note 5
        unset($model[$iter]); // note 6
        return true;
    }
    return false;
}

?>

Output

As shown above.

Explanation

We make use of the code from How to display directory tree using GtkTreeView - Part 2 - add folder icon? to display the directory tree.

What's new here:

  1. Register the signal 'key-press-event' on the treeview so that we can detect the 'Delete' key.
  2. Check for the 'Delete' key.
  3. Get the pointer to the GtkTreeSelection associated with the treeview.
  4. Get the model and iter of the selected row.
  5. Make sure user has selected something before we proceed.
  6. Delete the node from the tree model. Note that this only removes the node from the model. If you want the files/folders to be deleted, you have to "manually" delete the file from the system.

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