Difference between hooks Plugin_loaded and admin_int?

Question

As per my understanding, functions attached to plugin_loaded and admin_init hooks are called whenever any admin page is loaded. What's the difference between them?

Answer 1

plugins_loaded fires once activated plugins have loaded. This fires on both admin and public screens.

admin_init fires as an admin screen or script is being initialized. This fires only on admin screens.

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The typical order for firing of hooks on the admin screen is:

1. muplugins_loaded - this is the first hook available to must-use plugins
2. registered_taxonomy
3. registered_post_type
4. plugins_loaded - this is the first hook available to regular plugins
5. auth_cookie_valid
6. set_current_user
7. load_textdomain
8. sanitize_comment_cookies
9. setup_theme
10. unload_textdomain
11. after_setup_theme - this is the first hook available to themes
12. init
13. widgets_init
14. register_sidebar
15. wp_register_sidebar_widget
16. wp_default_styles
17. wp_default_scripts
18. debug_bar_enqueue_scripts
19. wp_loaded - This hook is fired once WP, all plugins, and the theme are fully loaded and instantiated.
20. auth_redirect
21. admin_menu
22. pre_get_users
23. pre_user_query
24. admin_init
25. ... lots of other stuff

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As you can see, a lot happens between plugins_loaded and admin_init.

Hooks on the public side are similar to those above, with the notable absence of admin_init.