Adminhtml Form Button Value not Working

Question

I created a form in the adminhtml, all other fields are working well (ie., text, select, etc). However, I tried adding a button in the list of fields but it seems it's not picking up the value:

$fieldset->addField('test_button', 'button', array(
 'name' => 'test_button',
 'value' => 'Test Me',
 'label' => 'Click the button to test',
));

Output is just:

<input id="test_button" name="test_button" value="" type="button">

Note that the value is empty, thus button is just a blank button.

Answer 1

I got it now, instead of using $form->setValues(), I used $form->addValues() as the former overrides the value of the fields.

Answer 2

If we want to show the provided value for the button than we have to change the function _prepareForm() used to load the admin form to use function addValues() instead of setValues().

protected function _prepareForm()
{
 //create form structure
 $this->_form = new Varien_Data_Form();
 $this->setForm($this->_form);
 $this->model = Mage::registry('Namespace_Module');
 $this->_prepareRegularForm();
 //set form values
 $data = Mage::getSingleton('adminhtml/session')->getFormData();
 if ($data) {
 $this->_form->addValues($data);
 Mage::getSingleton('adminhtml/session')->setFormData(null);
 }
 elseif ($this->model) {
 //Using addValues() instead of setValues()
 $this->_form->addValues($this->model->getData());
 }
 return parent::_prepareForm();
}