How to add depended form field in magento admin

Question

I am not so familiar with magento so i am facing some trouble
I am creating a form in magento admin & trying to add depended form field eg- parent field is dropdown type & name is amount_type options are flat_option & percentage_option

child field are text type having name flat_value & percentage_value

So my requirment flat_value & percentage_value are hidden at first after that if i select flat_option in amount_type then show flat_value & in select percentage_option then show percentage_option.

my tried code is

$fieldset->addField('amount_type', 'select', array(
            'name' => 'amount_type',
            'label' => Mage::helper('adminhtml')->__('Amount Type'),
            'title' => Mage::helper('adminhtml')->__('Amount Type'),
            'class' => '',
            'required' => true,
            'value'     => '1',
    'values'    => array('-1'=>'Please Select','1' => 'flat_option', '2' => 'percentage_option'),
                )
        );

$fieldset->addField('flat_value', 'text', array(
            'name' => 'flat_value',
            'label' => Mage::helper('adminhtml')->__('flat amount'),
            'title' => Mage::helper('adminhtml')->__('flat amount'),
            'class' => 'validate-number',
            'required' => true,
                )
        );

$fieldset->addField('percentage_value', 'text', array(
            'name' => 'percentage_value',
            'label' => Mage::helper('adminhtml')->__('Percentage amount'),
            'title' => Mage::helper('adminhtml')->__('Percentage amount'),
            'class' => 'validate-number validate-digits-range digits-range-0-100',
            'required' => true,
                )
        );

$this->setChild('form_after', $this->getLayout()
    ->createBlock('adminhtml/widget_form_element_dependence')
        ->addFieldMap('amount_type', 'amount_type')
        ->addFieldMap('flat_value', 'flat_value)
        ->addFieldDependence('flat_value', 'amount_type', 1)
);

$this->setChild('form_after', $this->getLayout()
    ->createBlock('adminhtml/widget_form_element_dependence')
        ->addFieldMap('amount_type', 'amount_type')
        ->addFieldMap('percentage_value', 'percentage_value')
        ->addFieldDependence('percentage_value', 'amount_type', 2)
);

Tanks in advance for help

Answer 1

Try the below code

$accountField = $fieldset->addField('amount_type', 'select', array(
            'name' => 'amount_type',
            'label' => Mage::helper('adminhtml')->__('Amount Type'),
            'title' => Mage::helper('adminhtml')->__('Amount Type'),
            'class' => '',
            'required' => true,
            'value'     => '1',
    'values'    => array('-1'=>'Please Select','1' => 'flat_option', '2' => 'percentage_option'),
                )
        );

$flatField = $fieldset->addField('flat_value', 'text', array(
            'name' => 'flat_value',
            'label' => Mage::helper('adminhtml')->__('flat amount'),
            'title' => Mage::helper('adminhtml')->__('flat amount'),
            'class' => 'validate-number',
            'required' => true,
                )
        );

$presentageField = $fieldset->addField('percentage_value', 'text', array(
            'name' => 'percentage_value',
            'label' => Mage::helper('adminhtml')->__('Percentage amount'),
            'title' => Mage::helper('adminhtml')->__('Percentage amount'),
            'class' => 'validate-number validate-digits-range digits-range-0-100',
            'required' => true,
                )
        );

$this->setChild('form_after', $this->getLayout()
    ->createBlock('adminhtml/widget_form_element_dependence')
        ->addFieldMap($accountField->getHtmlId(), $accountField->getName())
        ->addFieldMap($flatField->getHtmlId(), $flatField->getName())
        ->addFieldMap($presentageField->getHtmlId(), $presentageField->getName())
         ->addFieldDependence(
                $presentageField->getName(),
                $accountField->getName(),
                2
            )
            ->addFieldDependence(
                $flatField->getName(),
                $accountField->getName(),
                1
            )
);

Refer this Link you will get better understanding of field dependency