Prevent Drupal form from being called again on submit? - drupal-7

Question

In Drupal 7, I have this code.
It defines the hard-coded string my_module_custom_route_form as the form ID and use drupal_get_form to initialize a form. And there is one submit button.
Visit this route /custom_route, the output is
initialize form
If you submit the form, the output is
initialize form
submitted
The problem is this: The submission of this form will call my_module_custom_route_form again.
How can I prevent it from being called again on submission? If you know why Drupal does this, I would also like to know.
function my_module_menu() {
$items = array();
$items['custom_route'] = array(
"page arguments" => array("my_module_custom_route_form"),
"page callback" => "drupal_get_form",
"access callback" => TRUE,
);
return $items;
}
function my_module_custom_route_form($form, &$form_state){
print_r("initialize form");
$form = array();
$form["button"] = array(
"#type" => "submit",
"#value" => "submit"
);
return $form;
}
function my_module_custom_route_form_submit($form, &$form_state){
print_r("<br />submitted");
exit;
}

Answer 1

I think what you need is this:
Set $form_state['redirect'] = false in the submit handler.
See https://drupal.stackexchange.com/questions/26347/prevent-redirect-after-form-submit
Hope that helps!

Answer 2

I know that this is an old question, but the question is still relevant - I ran into the same problem. In my case it is definitely a problem, since the form in the block claims a queue item for processing, but when the form builder is called a second time, of course the item is blocked in the queue.
Clicking the button on a non-ajaxified form causes the page to reload. In the case of the block, this calls the block_view function, which rebuilds the form from 0.
I solved this by ajaxifying the submit button. Then the submission is called without re-viewing the block (and rebuilding the form, as is the case here). There is a nice ajax_example in the examples module, for those who are new to ajax forms.