Save data from multiple checkbox metaboxes in Wordpress - php

Question

I'm learning how to add metaboxes to posts. I would like to create a group of metaboxes with text inputs and multiple checboxes. For now the checkboxes are just put there like that, but eventually they will be generated by a foreach loop with content from another place, so it's important for me to give them names like entry[0], entry[1] and so on. They have to be saved by a loop as I will not know how many will be generated.
This is what I have so far:
// adding the metaboxes
function add_post_reference() {
add_meta_box('post-reference', 'Reference', 'referenceCallBack', 'languagecourses', 'side', 'high');
}
add_action('add_meta_boxes', 'add_post_reference');
// callback function
function referenceCallBack($post) {
wp_nonce_field( 'reference_meta_box', 'reference_nonce' );
$name_value = get_post_meta( $post->ID, '_post_reference_name', true );
$link_value = get_post_meta( $post->ID, '_post_reference_link', true );
trying to do the same as above with my checkboxes but I don't know what to put there:
$teachers_value = get_post_meta( $post->ID, 'what do I put here?', true ); // what do I put here?
Echoing the html structure now (the text inputs work (values get saved), I'm trying to figure out how to make the checkboxes save as well:
echo '<label for="reference-name">'. 'Reference Name' .'</label>';
echo '<input type="text" id="reference-name" name="post_reference_name" placeholder="Example" value="'.$name_value.'" size="25"/>';
echo '<p class="howto">'. 'Add the name of the reference' .'</p>';
echo '<label for="reference-link">'. 'Reference Link' .'</label>';
echo '<input type="text" id="reference-link" name="post_reference_link" placeholder="http://www.example.com/" value="'.$link_value.'" size="25"/>';
echo '<p class="howto">'. 'Add the link of the reference' .'</p>';
// my checkboxes
echo '<input type="checkbox" name="entry[0]" value="moredata">';
echo '<input type="checkbox" name="entry[1]" value="moredata">';
echo '<input type="checkbox" name="entry[2]" value="moredata">';
echo '<input type="checkbox" name="entry[3]" value="moredata">';
echo '<input type="checkbox" name="entry[4]" value="moredata">';
}
function save_post_reference( $post_id ) {
if ( ! current_user_can( 'edit_post', $post_id ) ) {
return;
}
if ( ! isset( $_POST['reference_nonce'] ) ) {
return;
}
if ( ! wp_verify_nonce( $_POST['reference_nonce'], 'reference_meta_box' ) ) {
return;
}
if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
return;
}
if ( ! isset( $_POST['post_reference_name'] ) || ! isset( $_POST['post_reference_link'] ) ) {
return;
}
$reference_name = sanitize_text_field( $_POST['post_reference_name'] );
$reference_link = sanitize_text_field( $_POST['post_reference_link'] );
// looping through the checkboxes
for ($i = 0; $i < 5; $i++) {
$teachers_names = sanitize_text_field($_POST['entry'][$i]);
}
update_post_meta( $post_id, '_post_reference_name', $reference_name );
update_post_meta( $post_id, '_post_reference_link', $reference_link );
Again, what do I put here?
update_post_meta( $post_id, 'whatdoIputhere?', $teachers_names); // what do I put here?
}
add_action( 'save_post', 'save_post_reference' );
Could anybody please help me on that?

Answer 1

Your HTML code should be like :
echo '<input type="checkbox" name="entry[]" value="moredata">';
echo '<input type="checkbox" name="entry[]" value="moredata">';
echo '<input type="checkbox" name="entry[]" value="moredata">';
echo '<input type="checkbox" name="entry[]" value="moredata">';
echo '<input type="checkbox" name="entry[]" value="moredata">';
now you will save the data :
key = 'entry';
$values_to_save = array();
$new_values = $_POST['entry'];
$existing_values = get_post_meta( $post_id, $key, true ) ;
if(!empty($existing_values)){
foreach((array) $existing_values as $existing_value){
$values_to_save[] = $existing_value;
}
}
if(!empty($new_values)){
foreach((array) $new_values as $new_value ){
$values_to_save[] = $new_value ;
}
}
update_post_meta( $post_id, $key, $values_to_save );
Now to fetch the data use the below code :
$key = 'entry';
$values = get_post_meta( $post_id, $key, true );
foreach((array) $values as $value){
echo $value . '<br>';
}

Answer 2

Ok, I updated my functions with your code and this is how it looks now:
function add_post_reference() {
add_meta_box('post-reference', 'Reference', 'referenceCallBack', 'languagecourses', 'side', 'high');
}
add_action('add_meta_boxes', 'add_post_reference');
// callback
function referenceCallBack($post) {
wp_nonce_field( 'reference_meta_box', 'reference_nonce' );
$name_value = get_post_meta( $post->ID, '_post_reference_name', true );
$link_value = get_post_meta( $post->ID, '_post_reference_link', true );
$key = 'entry';
$values = get_post_meta( $post_id, $key, true );
foreach((array) $values as $value){
echo $value . '<br>';
}
echo '<label for="reference-name">'. 'Reference Name' .'</label>';
echo '<input type="text" id="reference-name" name="post_reference_name" placeholder="Example" value="'.$name_value.'" size="25"/>';
echo '<p class="howto">'. 'Add the name of the reference' .'</p>';
echo '<label for="reference-link">'. 'Reference Link' .'</label>';
echo '<input type="text" id="reference-link" name="post_reference_link" placeholder="http://www.example.com/" value="'.$link_value.'" size="25"/>';
echo '<p class="howto">'. 'Add the link of the reference' .'</p>';
echo '<input type="checkbox" name="entry[]" value="moredata">';
echo '<input type="checkbox" name="entry[]" value="moredata">';
echo '<input type="checkbox" name="entry[]" value="moredata">';
echo '<input type="checkbox" name="entry[]" value="moredata">';
echo '<input type="checkbox" name="entry[]" value="moredata">';
}
function save_post_reference( $post_id ) {
if ( ! current_user_can( 'edit_post', $post_id ) ) {
return;
}
if ( ! isset( $_POST['reference_nonce'] ) ) {
return;
}
if ( ! wp_verify_nonce( $_POST['reference_nonce'], 'reference_meta_box' ) ) {
return;
}
if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
return;
}
if ( ! isset( $_POST['post_reference_name'] ) || ! isset( $_POST['post_reference_link'] ) ) {
return;
}
$reference_name = sanitize_text_field( $_POST['post_reference_name'] );
$reference_link = sanitize_text_field( $_POST['post_reference_link'] );
$key = 'entry';
$values_to_save = array();
$new_values = $_POST['entry'];
$existing_values = get_post_meta( $post_id, $key, true ) ;
if(!empty($existing_values)){
foreach((array) $existing_values as $existing_value){
$values_to_save[] = $existing_value;
}
}
if(!empty($new_values)){
foreach((array) $new_values as $new_value ){
$values_to_save[] = $new_value ;
}
}
update_post_meta( $post_id, $key, $values_to_save );
update_post_meta( $post_id, '_post_reference_name', $reference_name );
update_post_meta( $post_id, '_post_reference_link', $reference_link );
}
add_action( 'save_post', 'save_post_reference' );
One thing I change was that key = to $key = as otherwise it was throwing an error.
And still - no change... one thing I thought about is that maybe it does save the data, but the checkboxes remain unchecked?