how to get list of all buttons in civicrm hook_buildform?

Question

I need to add one more button to an event form but right now when I use

addButtons

it overrides existing buttons How can I make sure the buttons which I add are updated instead of replacing the existing ones?

function custom_changes_civicrm_buildForm($formName, &$form){
  if($formName == 'CRM_Event_Form_ManageEvent_EventInfo' && $user->uid){
        $buttons = array(
        array(
          'type' => 'upload',
          'name' => ts('Request for Approval'),
          'isDefault' => TRUE,
        ),
      );
      $form->addButtons($buttons);

  }
}

In the CRM\Event\Form\ManageEvent.php
I see there are protected variables, which I am unable to add it in the conditions inside hook_buildForm
e.g. _cancelURL, _single , so how can I override it using hook_buildForm , an
example would be helpful.

 /**
   * Build the form object.
   */
  public function buildQuickForm() {
    $session = CRM_Core_Session::singleton();

    $this->_cancelURL = CRM_Utils_Array::value('cancelURL', $_POST);

    if (!$this->_cancelURL) {
      if ($this->_isTemplate) {
        $this->_cancelURL = CRM_Utils_System::url('civicrm/admin/eventTemplate',
          'reset=1'
        );
      }
      else {
        $this->_cancelURL = CRM_Utils_System::url('civicrm/event/manage',
          'reset=1'
        );
      }
    }

    if ($this->_cancelURL) {
      $this->addElement('hidden', 'cancelURL', $this->_cancelURL);
    }

    if ($this->_single) {
      $buttons = array(
        array(
          'type' => 'upload',
          'name' => ts('Save'),
          'isDefault' => TRUE,
        ),
        array(
          'type' => 'upload',
          'name' => ts('Save and Done'),
          'spacing' => '                 ',
          'subName' => 'done',
        ),
        array(
          'type' => 'cancel',
          'name' => ts('Cancel'),
        ),
      );
      $this->addButtons($buttons);
    }
    else {
      $buttons = array();
      if (!$this->_first) {
        $buttons[] = array(
          'type' => 'back',
          'name' => ts('Previous'),
          'spacing' => '     ',
        );
      }
      $buttons[] = array(
        'type' => 'upload',
        'name' => ts('Continue'),
        'spacing' => '         ',
        'isDefault' => TRUE,
      );
      $buttons[] = array(
        'type' => 'cancel',
        'name' => ts('Cancel'),
      );

      $this->addButtons($buttons);
    }
    $session->replaceUserContext($this->_cancelURL);
    $this->add('hidden', 'is_template', $this->_isTemplate);
  }

Answer 1

You will need to over-ride the button to include existing + new button through buildform. The other option is to add button using smarty in tpl file using below snippet

{crmButton p='civicrm/request' q="action=browse&reset=1&gid=$gid" icon="th-list"}{ts}Request for Approval{/ts}{/crmButton}

HTH

Pradeep