|
Problem This is in response to Manar's post titled "How to disconnect an event?"
He has set up a button-press-event, and he would like to switch the signal handler processing the button-press-event depending on some conditions as shown below:
In this example, the first time you click the box, it will be handled by on_button_press1() and the box color change to green as shown below:
When you press the box a second time, it will be handled by on_button_press2() and the box color change to yellow as shown below:
Thereafter, when you click on the box further, the signal handlers will alternate between on_button_press1() and on_button_press2().
Solution
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
| <?php
$window = new GtkWindow();
$window->set_size_request(400, 175);
$window->connect_simple('destroy', array('Gtk','main_quit'));
$window->add($vbox = new GtkVBox());
// display title
$title = new GtkLabel("Switching signal handlers on the fly\n".
"Part 1 - using disconnect / connect");
$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);
$vbox->pack_start(new GtkLabel(), 0);
$label = new GtkLabel('Click on the blue sqaure once. '.
'It will change to green.');
$vbox->pack_start($label, 0);
$signal_id = setup_colorbox('#0000ff', 'blue', $vbox); // note 1
$window->show_all();
Gtk::main();
function setup_colorbox($color, $label, $vbox) {
$hbox = new GtkHBox();
$hbox->set_size_request(30, 30);
$eventbox = new GtkEventBox();
$eventbox->add($hbox);
$eventbox->modify_bg(Gtk::STATE_NORMAL, GdkColor::parse($color));
$signal_id = $eventbox->connect('button-press-event',
'on_button_press1'); // note 2
$hbox = new GtkHBox();
$vbox->pack_start($hbox, 0);
$hbox->pack_start(new GtkLabel());
$hbox->pack_start($eventbox, 0);
$hbox->pack_start(new GtkLabel());
return $signal_id;
}
function on_button_press1($eventbox, $event) {
if ($event->type!=Gdk::BUTTON_PRESS) return false; // note 9
echo "on_button_press1!\n";
$eventbox->modify_bg(Gtk::STATE_NORMAL,
GdkColor::parse('#00ff00')); // note 3
global $signal_id;
$eventbox->disconnect($signal_id); // note 4
|
- Note that this is only 70% of the sample code. You have to be a registered member to see the entire sample code. Please login or register.
- Registration is free and immediate.
- Have some doubt about the registration? Please read this forum article.
Explanation
- Set up the blue color box.
- Set up the
button-press-event signal. Don't forget to take note of the signal handler id.
- Change the color box from blue to green.
- Disconnect the
button-press-event signal.
- Connect to eventbox to the other signal handler.
- Change the color box from green to yellow.
- Disconnect the
button-press-event signal.
- Connect to eventbox to the other signal handler.
- Added this here to handle only single-click. Try removing this line and see what happens.
Related Links
User reviews There are no user reviews yet. Note: You have to be a registered member to leave a comment. Free registration here. |
