taxonomy_radio is not showing anything in the front-end in cmb2 - php

Question

I am building a website in where I want to show the tag selected from the custom fields (mainly from radio button). I have setup the cmb2 as like below the codes..
add_action('cmb2_admin_init', 'custom_metaboxes');
function custom_metaboxes() {
$metabox = new_cmb2_box( array(
'object_types' => array( 'post'), //for the post
'title' => 'Additional Fields',
'id' => 'additional'
)
);
// showing in the admin panel
$metabox -> add_field( array(
'name' => 'Taxonomy List',
'desc' => 'This get the list of taxonomy',
'id' => 'taxonomy_list',
'type' => 'taxonomy_radio',
'taxonomy' => 'post_tag',
'default' => 'ami'
)
);
}
Ok, that is working in the post section. My tags are shown in the radio buttons, That's working. But when I tried to show the the selected tag in the front-end using
echo get_post_meta( get_the_id(), 'taxonomy_list', true )// returns nothing
nothing is echoing. Then tried var_dump function it returns string(0) "". What are the problems are working behind the scene.
Anyone please find out what the problems are.

Answer 1

The problem can be solved by using cmb2-2.0.2 version. And here is the code:
<?php
add_action( 'cmb2_init', 'yourprefix_register_demo_metabox' );
function yourprefix_register_demo_metabox() {
$prefix = '_yourprefix_demo_';
$cmb_demo = new_cmb2_box( array(
'id' => $prefix . 'additional',
'title' => 'Additional Fields',
'object_types' => array('page')
) );
$cmb_demo->add_field( array(
'name' => 'Taxonomy List',
'desc' => 'This get the list of taxonomy',
'id' => $prefix . 'taxonomy_list',
'type' => 'taxonomy_radio',
'taxonomy' => 'post_tag'
) );
}
?>
And in frontend you need to write:
<?php
$prefix = '_yourprefix_demo_';
echo get_tag(get_post_meta(get_the_ID(), $prefix.'taxonomy_list', true)[0])->name;
?>