342. How to reorder columns in a treeview?

Problem

Suppose you have set up a treeview, and you would like to allow users to reorder or shift columns around (by dragging the treeview column header) as shown below:

How to reorder columns in a treeview?


Solution

  • By default, a column is not reorderable.
  • To set a column to be reorderable, use the method GtkTreeViewColumn::set_reorderable(true).
  • Note that in this example, I've set column 1 to 3 to be reorderable. The first column (i.e. column 0) remains not reorderable.

Sample Code

1   
 2   
 3   
 4   
 5   
 6   
 7   
 8   
 9   
 10   
 11   
 12   
 13   
 14   
 15   
 16   
 17   
 18   
 19   
 20   
 21   
 22   
 23   
 24   
 25   
 26   
 27   
 28   
 29   
 30   
 31   
 32   
 33   
 34   
 35   
 36   
 37   
 38   
 39   
 40   
 41   
 42   
 43   
 44   
 45   
 46   
 47   
 48   
 49   
 50   
 51   
 52   
 53   
 54   
 55   
 56   
 57   
 58   
 59   
 60   
 61   
 62   
 63   
 64   
 65   
 66   
 67   
 68   
 69   
 70   
 71   
 72   
 73   
 74   
 75   
 76   
 77   
 78   
 79   
 80   
 81   
 82   
 83   
 84   
 85   
 86   
 87   
 88   
 89   
 90   
 91   
 92   
 96   
 97   
 98   
 99   
100   
101   
102   
103   
104   
105   
106   
107   
108   
109   
110   
111   
112   
113   
<?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("Display 2D Array in GtkTreeView - Part 5\n".
"                       get user selection");
$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 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);
        if ($col>0) $column->set_reorderable(true); // note 1

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

// 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);
}

// 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);
    print "You have selected $desc: $qty ($price)\n";
}

?>

Output

As shown above.

 

Explanation

We make use of the code from How to display a 2D array in GtkTreeView - Part 5 - get user selection?

What's new here:

  1. Make column 1 to 3 reorderable.

Related Links

Add comment

Security code
Refresh