BuddyPress.org

Ok, well I had to figure this one out. It’s a bit of a lengthy solution. I’m not going to explain everything, as I can’t for either lack of knowledge or fear of being incorrect. I’ll just give you the code, tell you what it does, and where it goes.

First, lets add the favorite button to the comments template. Find comment.php (in /activity) and add the code:

		<?php global $activities_template; ?>
		<?php if ( bp_activity_can_favorite() ) : ?>
			<?php
				$my_fav_count = bp_activity_get_meta( bp_get_activity_comment_id(), 'favorite_count' );
				
				$my_fav_count = "<span>".$my_fav_count."</span>";
				
				$is_favorite = apply_filters( 'bp_get_activity_is_favorite', in_array( bp_get_activity_comment_id(), $activities_template->my_favs ) );
			?>

			<?php if ( !$is_favorite ) : ?>

				<a href="<?php echo apply_filters( 'bp_get_activity_favorite_link', wp_nonce_url( home_url( bp_get_activity_root_slug() . '/favorite/' . bp_get_activity_comment_id() . '/' ), 'mark_favorite' ) ); ?>" class="tooltip-trigger fav bp-secondary-action bp-primary-action" title="<?php echo god_get_favorited_usernames(bp_get_activity_comment_id()); ?>" style="position:relative;"><?php _e( 'Like', 'buddypress' ); ?><?php echo $my_fav_count; ?></a>

			<?php else : ?>

				<a href="<?php echo apply_filters( 'bp_get_activity_favorite_link', wp_nonce_url( home_url( bp_get_activity_root_slug() . '/favorite/' . bp_get_activity_comment_id() . '/' ), 'mark_favorite' ) ); ?>" class="tooltip-trigger unfav bp-secondary-action bp-primary-action" title="<?php echo god_get_favorited_usernames(bp_get_activity_comment_id()); ?>" style="position:relative;"><?php _e( 'Unlike', 'buddypress' ); ?><?php echo $my_fav_count; ?></a>

			<?php endif; ?>

		<?php endif; ?>	

This code simply adds the buttons, and gets all the necessary info and variables.

Then, you’re going to need to modify the buddypress javascript. I personally modified both global.js and buddypress.js (through overriding in my template, which is a topic for a whole other thread), though I might be wrong in this. At any rate, look for the line (around 264 in buddypress.js):

var parent = target.closest('.activity-item');

and change it to

var parent = target.closest('li');

The reason we changed this line is so that our custom favorite button doesn’t default to grabbing the top level activity id. Now you can actually favorite comments!

But wouldn’t it be nice if the user received a notification when someone favorited their activity? Add this bad boy to functions.php

add_action("bp_activity_add_user_favorite","favorite_notification", 10, 2);

function favorite_notification( $activity_id, $user_id = 0){
	// By type and item_id
	if($user_id != $activities["activities"][0]->user_id){
		$activities = bp_activity_get_specific( array( 'activity_ids' => $activity_id, 'display_comments' => true) );
		
		bp_core_add_notification( $activity_id, $activities["activities"][0]->user_id, "notifier", bp_core_get_username(bp_loggedin_user_id())." liked: '".substr($activities["activities"][0]->content,0,20)."...'", $activity_id ) ;		
	}
}

Hope this helped someone. It mostly works for me.