340. How to delete multiple rows in GtkTreeView using GtkListStore - Part 1?

Problem

Suppose you would like to allow users to delete multiple rows in a linear list (i.e. using GtkTreeView with GtkListStore) as shown below:

How to delete multiple rows in GtkTreeView using GtkListStore - Part 1?


Solution


Sample Code

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<?php
$window = new GtkWindow();
$window->set_size_request(400, 210);
$window->connect_simple('destroy', array('Gtk','main_quit'));
$window->add($vbox = new GtkVBox());

// display title
$title = new GtkLabel("Delete multiple rows in linear list - 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);

$vbox->pack_start($hbox = new GtkHBox(), 0);
$hbox->pack_start($button = new GtkButton('Delete Selected Rows'), 0);
$button->connect('clicked', 'on_process_button');

// the 2D table
$data = array(
array('row0', 'item 42', 2, 3.1),
array('row1', 'item 36', 20, 6.21),
array('row2', 'item 21', 8, 9.36),
array('row3', 'item 10', 11, 12.4),
array('row4', 'item 7', 5, 15.5),
array('row5', 'item 4', 17, 18.6),
array('row6', 'item 3', 20, 21.73));

$view = display_table($vbox, $data);

$window->show_all();
Gtk::main();

function display_table($vbox, $data) {

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

    // Creates the list store
    if (defined("GObject::TYPE_STRING")) {
        $model = new GtkListStore(GObject::TYPE_STRING, GObject::TYPE_STRING,
                    GObject::TYPE_LONG, GObject::TYPE_DOUBLE);
    } else {
        $model = new GtkListStore(Gtk::TYPE_STRING, Gtk::TYPE_STRING,
                    Gtk::TYPE_LONG, Gtk::TYPE_DOUBLE);
    }
    $field_header = array('Row #', 'Description', 'Qty', 'Price');
    $field_justification = array(0.0, 0.0, 0.5, 1.0);

    // Creates the view to display the list store
    $view = new GtkTreeView($model);
    $scrolled_win->add($view);

    // Creates the columns
    for ($col=0; $col<count($field_header); ++$col) {
        $cell_renderer = new GtkCellRendererText();
        $cell_renderer->set_property("xalign", $field_justification[$col]);
        $column = new GtkTreeViewColumn($field_header[$col],
            $cell_renderer, 'text', $col);
        $column->set_alignment($field_justification[$col]);
        $column->set_sort_column_id($col);

        // set the header font and color
        $label = new GtkLabel($field_header[$col]);
        $label->modify_font(new PangoFontDescription("Arial Bold"));
        $label->modify_fg(Gtk::STATE_NORMAL, GdkColor::parse("#0000FF"));
        $column->set_widget($label);
        $label->show();

        // setup self-defined function to display alternate row color
        $column->set_cell_data_func($cell_renderer, "format_col", $col);
        $view->append_column($column);
    }

    // pupulates the data
    for ($row=0; $row<count($data); ++$row) {
        $values = array();
        for ($col=0; $col<count($data[$row]); ++$col) {
            $values[] = $data[$row][$col];
        }
        $model->append($values);
    }

    $selection = $view->get_selection();
    $selection->set_mode(Gtk::SELECTION_MULTIPLE);
    return $view;
}

// self-defined function to format the price column
function format_col($column, $cell, $model, $iter, $col_num) {
    $path = $model->get_path($iter); // get the current path
    $row_num = $path[0]; // get the row number
    if ($col_num==3) {
        $amt = $model->get_value($iter, 3);
        $cell->set_property('text', '$'.number_format($amt,2));
    }
    $row_color = ($row_num%2==1) ? '#dddddd' : '#ffffff';
    $cell->set_property('cell-background', $row_color);
}

function on_process_button($button) {
    global $view;
    $model = $view->get_model();
    $selection = $view->get_selection();
    list($model, $selected_rows) =
        $selection->get_selected_rows();

    $i = 0;
    $rows_to_remove = array();
    foreach($selected_rows as $path) {
        $iter = $model->get_iter($path);
        $desc = $model->get_value($iter, 1);
        $qty = $model->get_value($iter, 2);
        $price = $model->get_value($iter, 3);
        print "Selection $i: $desc: $qty ($price)\n";
        ++$i;
        $rows_to_remove[] = $path[0]; // note 1
    }

    for ($i=count($rows_to_remove)-1; $i>=0; --$i) { // note 2
        print "remove row: $rows_to_remove[$i]\n";
        unset($model[$rows_to_remove[$i]]); // note 3
     }
}

?>

Output

As shown above.

 

Explanation

We make use of the code from How to process multiple selections in GtkTreeView?

What's new here:

  1. Store the corresponding path in the array $rows_to_remove.
  2. Note that we need to remove the paths in reverse order. Try removing the paths from $i=1 to count($rows_to_remove) and you will know what I mean.
  3. Remove this row!

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