345. How to set up combobox in treeview with colors - Part 3?

Problem

Please take a look at How to set up combobox in treeview with colors - Part 1? which shows you how to color-code the options of the pulldown menu as shown bwlow.

Andre Colomb wrote to me with a second method of displaying the options in color.

How to set up combobox in treeview with colors - Part 3?


Solution

  • The GtkCellRendererCombo generates the pulldown menu on the fly when you click the down arrow.
  • In the previous method, Andre gets hold of the pointer to the combobox renderer used by that transient pulldown menu.
  • Andre's new approach was to remove the original combobox renderer and attach a new one to it.

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("Combobox in treeview with color - Part 3");
$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(), 0, 0);

// the 2D table
$data = array(
array('row0', 'item 1', 2, 3.1),
array('row1', 'item 4', 5, 6.21),
array('row2', 'item 7', 8, 9.36),
array('row3', 'item 10', 11, 12.4),
array('row4', 'item 21', 14, 15.5),
array('row5', 'item 36', 17, 18.6),
array('row6', 'item 42', 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, GObject::TYPE_STRING);
    } else {
        $model = new GtkListStore(Gtk::TYPE_STRING, Gtk::TYPE_STRING,
            Gtk::TYPE_LONG, Gtk::TYPE_DOUBLE, Gtk::TYPE_STRING);
    }
    $field_header = array('Row #', 'Description', 'Qty', 'Price');

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

    // creates columns
    for ($col=0; $col<count($field_header); ++$col) {
        $cell_renderer = new GtkCellRendererText();
        $column = new GtkTreeViewColumn($field_header[$col],
            $cell_renderer, 'text', $col);
        $column->set_cell_data_func($cell_renderer, "format_col", $col);
        $view->append_column($column);
    }

    // setup combo box
    $cell_renderer = new GtkCellRendererCombo();
    if (defined("GObject::TYPE_STRING")) {
        $category = new GtkListStore(GObject::TYPE_STRING, 
            GObject::TYPE_STRING); // note 1
    } else {
        $category = new GtkListStore(Gtk::TYPE_STRING, 
        Gtk::TYPE_STRING); // note 1
    }
    $options = array('grp 1'=>'#ff0000', 'grp 2'=>'#00ff00',
        'grp 3'=>'#0000ff', 'grp 4'=>'#ffff00');
    foreach($options as $option=>$color) { // note 1
        $category->append(array($option, $color));
    }
    $cell_renderer->set_property('model', $category);
    $cell_renderer->set_property('text-column', 0);
    $cell_renderer->set_property('editable', true);
    $cell_renderer->set_property('has-entry', false); // note 2
    $cell_renderer->connect('editing-started', 'editing_started'); // note 3
    $cell_renderer->connect('edited', 'on_combo', $model);

    $column = new GtkTreeViewColumn('Category', $cell_renderer, 'text', 4);
    $column->set_cell_data_func($cell_renderer, "format_col", 4);
    $view->append_column($column);

    $selection = $view->get_selection();
    $selection->connect('changed', 'on_selection');

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

        $model->append($values);
    }
}

// self-defined function to display alternate row color
function format_col($column, $cell, $model, $iter, $col_num) {
    $path = $model->get_path($iter);
    $row_num = $path[0];
    $row_color = ($row_num%2==1) ? '#dddddd' : '#ffffff';
    $cell->set_property('cell-background', $row_color);
}

function on_combo($renderer, $path, $selection, $model) {
    $iter = $model->get_iter($path);
    $model->set($iter, 4, $selection);
}

// the function that is called when user selects a row
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);
    $grp = $model->get_value($iter, 4);
    echo "You have selected $desc: $qty ($price) category = $grp\n";
}

function editing_started($renderer, $editable, $path) {
    $editable->clear(); // note 4
    $renderer = new GtkCellRendererText(); // note 5
    $editable->pack_start($renderer); // note 5
    $editable->set_cell_data_func($renderer, // note 6
                  'set_combo_renderer_background'); 
}

function set_combo_renderer_background($column, $renderer, $model, $iter) {
    // Set the options for the combobox
    $text = $model->get_value($iter, 0);
    $renderer->set_property('text', $text); // note 7

    // Get the relevant values
    $color = $model->get_value($iter, 1);
    // Set the background color
    $renderer->set_property('cell-background', $color); // note 8
}

?>

Output

As shown above.

 

Explanation

The above cocde is based on How to use GtkCellRendererCombo - Part 3 - process user selection?

What's new here:

  1. Note that we added one more column in the data model to store the color for each option.
  2. Note that this method only works for 'has-entry' set to false, i.e. the user is required select values from the pulldown menu. He or she are not allowed to enter his/her own values.
  3. Register for the signal 'editing-started' on the cellrenderer.
  4. Remove the original combobox renderer.
  5. Create a new cellrenderer and pack it into the cellview associated with the combobox.
  6. Set the cell display function for the cellrenderer of the combobox.
  7. Set the value of the option.
  8. Set the background color for this option.

Note

Note that using this method, there's no longer any error messages in the command line! (Please refer to How to set up combobox in treeview with colors - Part 1? for details.)

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