216. How to perform some actions when user click on treeview column header?

Problem

When a user click on the treeview column header, the default action is that column will be sorted.

Suppose you would like to perform some additional actions when the column header is clicked as shown below:

How to perform some actions when user click on treeview column header?


Solution

  • Register the signal clicked on the treeview column.

Sample Code

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<?php
$window = new GtkWindow();
$window->set_size_request(400, 200);
$window->connect_simple('destroy', array('Gtk','main_quit'));
$window->add($vbox = new GtkVBox());

// display title
$title = new GtkLabel("Perform some actions\n".
"when user click on column header");
$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);
$title->set_justify(Gtk::JUSTIFY_CENTER);
$alignment = new GtkAlignment(0.5, 0, 0, 0);
$alignment->add($title);
$vbox->pack_start($alignment, 0, 0);
$vbox->pack_start(new GtkLabel(), 0, 0);

// 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));

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);

        // set up event handler
        $column->connect('clicked', 'on_click_treeview_title', 
            $col, $field_header[$col]); // note 1
    }

    // 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->connect('changed', 'on_selection');
}

function format_col($column, $cell, $model, $iter, $col_num) {
    $path = $model->get_path($iter);
    $row_num = $path[0];
    if ($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_selection($selection) {
    list($model, $iter) = $selection->get_selected();
    $desc = $model->get_value($iter, 1);
    $qty = $model->get_value($iter, 2);
    $price = $model->get_value($iter, 3);
    print "You have selected $desc: $qty ($price)\n";
}

function on_click_treeview_title($column, $col_no, $col_title) {
    print "clicked on column: $col_title ($col_no)\n"; // note 2
    // perform your action here
    return true;
}

?>

Output

As shown above.

 

Explanation

The example above makes use of the code from How to display a 2D array in GtkTreeView - Part 5 - get user selection?

What's new here:

  1. Register the signal 'clicked' on the treeview column.
  2. Perform any actions here.

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