Problem
You have displayed a popup alert box in Part 1.
However, note that the OK button is right aligned. You would like the OK button to be centered as shown below:
Solution
The OK button can be centered by changing the layout style of the dialog action area with GtkButtonBox::set_layout(Gtk::BUTTONBOX_SPREAD)
Sample Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 24 25 43 44 45 46 47 48 49 50 51 52 53 54 55 59 60 61 62 64 66 67 68 69 70 71 72 73 74 75 76 77 | <?php $window = new GtkWindow(); $window->set_size_request(400, 150); $window->connect_simple('destroy', array('Gtk','main_quit')); $window->add($vbox = new GtkVBox()); // display title $title = new GtkLabel("Display Alert - Part 2"); $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); // add a small gap // setup the entry field $hbox = new GtkHBox(); $vbox->pack_start($hbox, 0, 0); $hbox->pack_start(new GtkLabel("Please enter your name:"), 0, 0); $name = new GtkEntry(); $hbox->pack_start($name, 0, 0); $name->connect('activate', 'on_activate'); // check user input function on_activate($widget) { $input = $widget->get_text(); echo "name = $input\n"; if ($input=='') alert("Please enter your name!"); $widget->grab_focus(); } // display popup alert box function alert($msg) { $dialog = new GtkDialog('Alert', null, Gtk::DIALOG_MODAL); $dialog->set_position(Gtk::WIN_POS_CENTER_ALWAYS); $top_area = $dialog->vbox; $top_area->pack_start($hbox = new GtkHBox()); $stock = GtkImage::new_from_stock(Gtk::STOCK_DIALOG_WARNING, Gtk::ICON_SIZE_DIALOG); $hbox->pack_start($stock, 0, 0); $hbox->pack_start(new GtkLabel($msg)); $dialog->add_button(Gtk::STOCK_OK, Gtk::RESPONSE_OK); $dialog->action_area->set_layout(Gtk::BUTTONBOX_SPREAD); // note 1 $dialog->set_has_separator(false); $dialog->show_all(); $dialog->run(); $dialog->destroy(); } $window->show_all(); Gtk::main(); ?> |
Output
As shown above.
Explanation
- The action_area of a GtkDialog is a GtkButtonBox.
- The layout of the buttons within the GtkButtonBox can be set with GtkButtonbox::set_layout().
- To center the OK button, we use
Gtk::BUTTONBOX_SPREAD
. - Other possible values of GtkButtonBoxStyle are here.
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