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Problem You would like to have a login prompt before your main program starts as shown below:
Solution We can easily use a GtkDialog to display the popup dialog box that prompts for username and password.
However, since a dialog box to prompt for data is frequently used, we will wrap this into a generic function called get_data(). We simply pass in the title of the dialog, and an array containing the field labels, the function will automatically display a dialog prompting user to enter the data.
When the user clicks the OK button, the data entered by the user will be returned to you as an array.
Sample Code 1
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| <?php
$login_success = login(); // calls the login function
if (!$login_success) exit(0); // exit if login not successful
// starts the main program only if login successful
$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("Login prompt - Part 1");
$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("User verified"));
$vbox->pack_start(new GtkLabel("Main program starts..."));
// the login function
function login() {
$count = 0;
while ($count<3) {
$data = get_data("Login", array("Username:", "Password:")); // get username and passwd
list($username, $password) = $data; // result of user input is returned as an array
if ($username=='user1' && $password=='phpgtk2') { // validate username and password
return true; // ok!
} else {
alert("Incorrect username and password!\nHint: username=user1\npassword=phpgtk2");
// not ok. alert user - note 2
}
++$count;
}
return false;
}
// display a popup dialog box to prompt for data
function get_data($title, $field_labels) {
$dialog = new GtkDialog($title, null, Gtk::DIALOG_MODAL); // create a new dialog
$dialog->set_position(Gtk::WIN_POS_CENTER_ALWAYS);
$top_area = $dialog->vbox; // get the top area
$top_area->pack_start($hbox = new GtkHBox());
$stock = GtkImage::new_from_stock(Gtk::STOCK_DIALOG_QUESTION, Gtk::ICON_SIZE_DIALOG);
$hbox->pack_start($stock, 0, 0); // stuff in the icon
// display the data entry form as table
$table = new GtkTable(); // create a new table
$row = 0;
$input = array(); // holds the ID of each GtkEntry
foreach ($field_labels as $field_label) {
$label = new GtkLabel($field_label);
$label->set_alignment(0,0); // left-justify the label
$table->attach($label, 0, 1, $row, $row+1); // insert the label into table
$input[$row] = new GtkEntry(); // create a new input field
$table->attach($input[$row], 1, 2, $row, $row+1); // add this besides the label
if (eregi("password", $field_label))
$input[$row]->set_visibility(false); // show password entry as '*'
++$row;
}
$hbox->pack_start($table);
$dialog->add_button(Gtk::STOCK_OK, Gtk::RESPONSE_OK); // add an OK button
$dialog->set_has_separator(false); // don't display the set_has_separator
$dialog->show_all(); // show the dialog
$dialog->run(); // the dialog in action
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Explanation
- When the user clicks "OK", we need to grab the user input before the dialog is destroyed. Since we have stored the ID of each GtkEntry in
$input[$row], we can easily get the value of the user input with GtkEntry::get_text().
- When user enters an invalid username or password, we alert the user with the
alert() function we have written in How to display a popup alert for required fields - Part 1?
Note
This is a very useful function. For example, you can use a one-liner:
get_data("Item Details", array("Item number", "Item description", "quantity", "unit price"));
to prompt user to enter the details of an item as shown below:
Of course, you can improve on the function to allow specification of the width of each field.
Please also note that there are a number of "annoyances" in this program:
- Pressing Enter does not automatically go to next field, or activates the "OK" button.
- Suppose the user enters an invalid username or password, the login form gets destroyed, the alert box appears, and the login form re-appears agian. Ideally the login form should only disappear after the user has keyed in the correct username and password.
We will fix this in the Part 2.
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