How to list all pages including child pages on a wordpress api settings??

Hi,

I’m using the code at, https://alisothegeek.com/2011/01/wordpress-settings-api-tutorial-1/ for a settings page and its pretty easy to learn the basic there.

However, I have a dropdown setting using this code,

$this->settings['example_select'] = array(
		'section' => 'general',
		'title'   => __( 'Example Select' ),
		'desc'    => __( 'This is a description for the drop-down.' ),
		'type'    => 'select',
		'std'     => '',
		'choices' => array(
			'choice1' => 'Other Choice 1',
			'choice2' => 'Other Choice 2',
			'choice3' => 'Other Choice 3'
		)
	);

where I want to list all the pages including their child pages(if there is) on the choices like,

'choices' => array(
	'choice1' => 'Home',
	'choice2' => '-Sub-Home',
	'choice3' => '-Sub-Home2',
        'choice4' => 'Contact-us',
        'choice4' => 'Sample Page'
)

Please help.
Thank you.