Change the contribution value programatically

Question

I'm trying to use the hook civicrm_buildForm to modify the contribution value based on specific logic.

I know I can use setDefaults() but I don't know how to get the field ID.

For this contribution form, I'm using a Price set.

Update

I tried this, but it didn't work:

if (isset($form->_priceSet['fields'])) {
    foreach ($form->_priceSet['fields'] as &$field) {
        if ($field['name'] == 'amount') {
            foreach ($field['options'] as &$option) {
                if ($option['label'] == 'Amount') {
                    $option['amount'] = 50;
                }
            }
        }
    }
}

Answer 1

Would suggest using the hook_civicrm_buildAmount hook as you won't need to handle the amount change at multiple places.