Using Filter on NULL Values in Views 3

Question

I'm using Drupal 7 with views 3.

I am listing the student fees in a view and one of the field in view results is pid (payment id) which has some numeric value or NULL value. The NULL value means the payment is unpaid. I have used a custom field handler to show in view result as paid and unpaid for pid = some value as Paid and pid = Null value as Unpaid.

I want a filter on this field also which will have a drop down of two options as paid and unpaid. Which views filter I should use and how can I rename the drop down options?

hook_views_data()

// Status of payment paid or unpaid if pid is null in joined result set : unpaid
    $data['fee_schedule_payments']['payment_status'] = array(
        'real field' => 'pid',
        'title' => t('Fee schedule payment status'), 
        'label' => t('Status'),
        'help' => t('Fee schedule payment status'), 
        'field' => array(
      'handler' => 'fee_management_handler_field_payment_status', 
      'click sortable' => TRUE, // This is use by the table display plugin.
    ), 
    'filter' => array(
      'handler' => 'views_handler_filter_WHICH_ONE_I_SHOULD_USE',
    ),
    ); 




class fee_management_handler_field_payment_status extends views_handler_field {
    function construct() {
    parent::construct();
    $this->additional_fields['pid'] = 'pid';
  }
  function render($values) {
    $pid = $this->get_value($values, 'pid');
    if (!empty($pid)) {
            return 'Paid';
        }
        return 'Unpaid';    
  }
};

Thanks in advance for your help.

Answer 1

I have implemented this custom filter. All Thanks and credit goes to Amar :). I am just sharing the code.

// Status of payment paid or unpaid if pid is null in joined result set : unpaid
    $data['fee_schedule_payments']['payment_status'] = array(
        'real field' => 'pid',
        'title' => t('Fee schedule payment status'), 
        'label' => t('Status'),
        'help' => t('Fee schedule payment status'), 
        'field' => array(
      'handler' => 'fee_management_handler_field_payment_status', 
      'click sortable' => TRUE, // This is use by the table display plugin.
    ), 
    'filter' => array(
      'handler' => 'fee_management_handler_filter_payment_status',
      'numeric' => TRUE,
    ),
    ); 

Handler

class fee_management_handler_filter_payment_status extends views_handler_filter_many_to_one {
  function get_value_options() {
    $this->value_options = array('1' => 'Paid', '0' => 'Unpaid');
  }

    function query() {
    // as per your database st
        ;


  }


}