Problem
Suppose you have set up a form and you want to prevent the user from submitting the form twice as shown below. There are two methods to accomplish this. This article shows the second method.
Solution
- In the second method, when the user clicks on the submit button the first time, we block the signal handler
on_click()
from being called when the signal'clicked'
is emitted. - We block a signal with the method GObject::block(
$handler_id
).
Sample Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 43 45 46 47 48 49 50 51 52 53 54 55 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 | <?php $window = new GtkWindow(); $window->set_size_request(400, 240); $window->connect_simple('destroy', array('Gtk','main_quit')); $window->add($vbox = new GtkVBox()); // display title $title = new GtkLabel("Prevent a form from submitting twice\n". "Part 2 - using GObject::block()"); $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); $fields = array('Item number', 'Item Description', 'Unit price', 'Quantity'); $field_size = array(120, 200, 80, 80); $entry = array(); // to store the text entries $table = new GtkTable(); display_table($table, $fields, $field_size); // display the table $vbox->pack_start($table); function display_table($table, $fields, $field_size) { global $entry; $row = 0; foreach ($fields as $field) { $label = new GtkLabel(" $field: "); $alignment = new GtkAlignment(1, .5, 0, 0); $alignment->add($label); $table->attach($alignment, 0, 1, $row, $row+1, Gtk::FILL, Gtk::SHRINK, 0, 0); $entry[$row] = new GtkEntry(); $alignment = new GtkAlignment(0, .5, 0, 0); $alignment->add($entry[$row]); $entry[$row]->set_size_request($field_size[$row], -1); $table->attach($alignment, 1, 2, $row, $row+1); ++$row; } } // create a submit button $button = new GtkButton('Submit'); $button->set_size_request(60, 28); $handler_id = $button->connect('clicked', 'on_click'); // note 1 $row = count($fields); $alignment = new GtkAlignment(0, 0.5, 0, 0); $alignment->add($button); $table->attach($alignment, 1, 2, $row, $row+1); $window->show_all(); Gtk::main(); function on_click($button) { global $fields, $entry; $i=0; foreach($fields as $field) { echo "$field: ".$entry[$i]->get_text()."\n"; ++$i; } global $handler_id; $button->block($handler_id); // note 2 } ?> |
Output
As shown above.
Explanation
The above example is based on How to align GtkEntry fields - Part 2?
What's new here:
- Make a copy of the handler id.
- Block the signal
'clicked'
!
Note
- To unblock a signal, use GObject::unblock(
$handler_id
). - To disconnect a signal completely, use GObject::disconnect(
$handler_id
).
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