7: Form API: managed_file: AJAX upload error "Undefined index ... in file_ajax_upload()"

Question

I have a problem with "AJAX: add more file fields". The Problem: i create new managed_file field and add AJAX function "add more file fields". When i try to upload a file with first static file field, it works fine. But when use function "add more fields" and try to upload a file with AJAX created field, get error "Notice: Undefined index: ... in file_ajax_upload() (Line 262 in .../modules/file/file.module)."

All Answers for Similar Questions here don't solve this Problem.

The code:

<?php
/**
* implimentation of hook_form_alter()
*/
function mymodule_form_alter(&$form, &$form_state, $form_id) {

}

/**
* implimentation of hook_form_FORM_ID_alter()
*/

function mymodule_form_block_admin_configure_alter(&$form, &$form_state, $form_id) {
 // Since the form builder is called after every AJAX request, we rebuild
  // the form based on $form_state.
  $num_checkboxes = !empty($form_state['values']['howmany_select']) ? $form_state['values']['howmany_select'] : 1;
  $form['howmany_select'] = array(
    '#title' => t('How many checkboxes do you want?'),
    '#type' => 'select',
    '#options' => array(
      1 => 1,
      2 => 2,
      3 => 3,
      4 => 4,
    ),
    '#default_value' => $num_checkboxes,
    '#ajax' => array(
      'callback' => 'ajax_example_autocheckboxes_callback',
      'wrapper' => 'checkboxes-div',
      // See ajax_example_autotextfields for an example of 'fade'.
      'effect' => 'fade',
      // Don't show any throbber...
      'progress' => array('type' => 'none'),
    ),
  );

  $form['checkboxes_fieldset'] = array(
    '#title' => t("Generated Checkboxes"),
    // The prefix/suffix provide the div that we're replacing, named by
    // #ajax['wrapper'] above.
    '#prefix' => '<div id="checkboxes-div">',
    '#suffix' => '</div>',
    '#type' => 'fieldset',
    '#description' => t('This is where we get automatically generated checkboxes'),
  );

  for ($i = 1; $i <= $num_checkboxes; $i++) {
   $form['checkboxes_fieldset']["slideshow_item_$i"] = array(
    '#title'    => t('Image')." $i:",
    '#type'     => 'managed_file',
    '#required' => FALSE,
    '#upload_location' => file_default_scheme() . '://mymodule_images/',
    '#upload_validators' => array(
      'file_validate_extensions' => array('gif png jpg jpeg'),
    ),
    '#tree' => TRUE,
    '#description' => t("Upload slideshow image. Allowed extensions: gif, png, jpg, jpeg."),
   );
  }
  return $form;
}



function ajax_example_autocheckboxes_callback($form, $form_state) {
  $form_state['rebuild'] = TRUE;
  return $form['checkboxes_fieldset'];
}

?>

I think the Problem is in $form_state. How i can refresh / rebuild $form_state? In ajax_example_autocheckboxes_callback i set $form_state['rebuild'] = TRUE; but without effect :(

Code Test Video:

http://www.youtube.com/watch?v=PtRiQorCTA4

I looking 3 days for a solution :-/

Helpful articles:

How to add more Fields using Form Api

https://drupal.org/node/752056

https://drupal.org/node/331941

How to wrap managed_file Form API element with custom HTML using #theme_wrappers?

Answer 1

You need to pass the parameters by reference if you want changes to persist outside the function scope:

function ajax_example_autocheckboxes_callback(&$form, &$form_state) {

Answer 2

OK, i have it!

The right way: "Submit button":

  $form['add_file_field'] = array(
                     '#type' => 'submit',
                     '#value' => t('Add one more'),
                     '#submit' => array('add_more_file_fields'),
                     '#ajax' => array(
                         'callback' => 'ajax_example_autocheckboxes_callback',
                         'wrapper' => 'ajax-generated-fields',
                     ),
                 );

Function, called after submit:

 function add_more_file_fields($form, &$form_state) {
   $form_state['values']['howmany_select']++;
   $form_state['rebuild'] = TRUE;
 }