341. How to delete multiple rows in GtkTreeView using GtkListStore - Part 2 - by pressing delete key?

Problem

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

In Part 1 the user has to press the "Delete Selected Rows" button to delete the rows.

In this Part 2, the user can also press the Delete key to delete the selected rows as shown below:

How to delete multiple rows in GtkTreeView using GtkListStore - Part 2 - by pressing delete key?


Solution

  • Register key-press-event on the treeview.
  • When the Delete key is pressed, delete the selected rows using the technique as outlined in Part 1.

Sample Code

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<?php
$window = new GtkWindow();
$window->set_size_request(400, 230);
$window->connect_simple('destroy', array('Gtk','main_quit'));
$window->add($vbox = new GtkVBox());

// display title
$title = new GtkLabel("Delete multiple rows in linear list\n".
"  Part 2 - by pressing Delete key");
$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(new GtkLabel(
    'You can also delete the rows by pressing the Delete key'), 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);
$view->connect('key-press-event', 'on_keypress'); // note 1

$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 delete_rows() { // note 3
    global $view;
    $model = $view->get_model();
    $selection = $view->get_selection();
    list($model, $selected_rows) =
        $selection->get_selected_rows();
    if (count($selected_rows)==0) return;

    $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];
    }

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

function on_process_button($button) {
    delete_rows();
}

function on_keypress($widget, $event) {
    if ($event->keyval==Gdk::KEY_Delete) { // note 2
        delete_rows(); // note 3
        return true;
    } else {
        return false;
    }
}

?>

Output

As shown above.

 

Explanation

We make use of the code from How to delete multiple rows in GtkTreeView using GtkListStore - Part 1?

What's new here:

  1. Register the signal key-press-event on the treeview.
  2. Check if this is Delete key.
  3. Yes, it's Delete key. Remove the selected rows!

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