Tìm Hiểu về Wordpress - part 10 pptx

77 • Show the blogroll In the Admin area, there is an entire area just for “links” (located in the same area with Posts and Pages). This area was once commonly referred to as the “Blogroll” but that term has gone a bit out of fashion. Regardless of what it’s called, the list of links managed in this area may be easily displayed with this: <?php wp_list_bookmarks(array( 'orderby' => 'name', // alphabetical 'order' => 'ASC', // starting at A 'limit' => -1, // unlimited, show ALL bookmarks 'title_li' => __('Bookmarks'), // include list item title 'title_before' => '<h2>', // tag before title 'title_after' => '</h2>', // tag after title )); ?> These are just a few example parameters, see the Codex at http://digwp.com/u/32. • Editable text area One of the things you may wish to include in a sidebar is an area of text that you can edit from the back end. There are a couple of different ways to do this. One way would be to use a “global custom field” (see page 66). Another way would be to use widgets. Widgets are WordPress’ way of allowing management of regions through the Admin, rather than having to edit theme files. One of the many different types of widgets is a generic “text” widget. If you have a “widgetized” sidebar, you can just drag this over into that area, enter your info, and save it. 78 3.6.4 Widgets, Widgets, Widgets “Widgetizing” a sidebar, or any other region for which you wish to have manageable areas, is pretty easy. And because widgets are standardized, plugins can make use of them and deliver special widgets that you can control directly from within the Admin area. We’ll look more into widgetization in section 4.8.1, but for now, this is the code that you would place into your theme file: <div id="sidebar"> <ul> <?php if (!function_exists('dynamic_sidebar') || !dynamic_sidebar()) : ?> <li><! stuff shown here in case no widgets active ></li> <?php endif; ?> </ul> </div> Now in your functions.php file, you “register” the sidebar with a custom function: if (function_exists('register_sidebar')) { register_sidebar(array( 'before_widget' => '<li id="%1$s" class="widget %2$s">', 'after_widget' => '</li>', 'before_title' => '<h2 class="widgettitle">', 'after_title' => '</h2>', )); } Now every widget you add will appear inside list tags with corresponding <h2> headings, which should fit well into the surrounding markup. Each widget will also have a unique ID and common class name (for potential CSS styling). More Sidebar Ideas For more great techniques and ideas for crafting the perfect sidebar, check out Section 4.4.1, “Side Content and Useful Menu Items.” 79 3.7.1 The Search Form WordPress provides built-in search functionality, and you should definitely share it with your visitors. It is an expected feature of most websites, providing a useful way for visitors to locate their favorite content. 3.7.2 Why is This a Separate File? It is very common for a WordPress theme to have a file called searchform.php. This is because the search form may be used in multiple theme files and in different locations, so placing it in its own file helps to keep things modular. Just like the sidebar, which you can include at your leisure with the get_sidebar() function, you can include your searchform.php in any other template file by calling this function: <?php get_search_form(); ?> This function accepts no other parameters, but of course if you had a good reason to rename searchform.php or keep it anywhere other than the root directory of your theme, you could just use the standard include code instead: <?php include(TEMPLATEPATH . '/inc/special-search-form.php'); ?> Where might you use this? • On the 404 page (404.php) • In the “else” part of The Loop • In the sidebar 3.7.3 Alternatives to WordPress Search The fact of the matter is that the WordPress built-in search kind of sucks. It lists things in chronological order based on whether or not it found any of your search 80 terms. When searching for your query, WordPress looks in the titles and content of your posts and pages. If the search terms aren’t located there, WordPress will tell you that nothing can be found. To make things worse, there is no advanced search functionality, meaning you have very little control as a user or as a theme developer as to how results are refined, returned, and displayed. There are ways of hacking together a decent WordPress search system, but it takes quite a bit of meddling. A much easier way to improve the WordPress’ default search functionality is either to replace it entirely with Google or install a plugin that will beef things up for you. Google Search http://digwp.com/u/53 As it happens, an alternative to WordPress search is to just use Google search instead. Not just generic Google full-web search, but rather a free service called the Google Custom Search Engine, with which you can integrate customized, site- specific search engines into any site. It’s easy and super-awesome. Search API Plugin http://digwp.com/u/54 This plugin provides a far more powerful searching system than the default WordPress search. With the Search API plugin, you can search different types of content, search within particular categories, use search operators like AND, OR, and NOT, and even search using a more comprehensive “fulltext” MySQL search. As if that weren’t cool enough, this plugin also integrates with Google Custom Search. Search Everything Instead of just looking at post titles and content to locate matching search terms, wouldn’t it be neat if WordPress searched through everything in your database? The Search Everything plugin does exactly that, telling WordPress to search through comments, drafts, attachments, and just about everything else. http://digwp.com/u/400 Each of the different search choices on CSS-Tricks activates a different Google Custom Search Engine. 81 3.8.1 The Footer Just like headers and sidebars, footers are one of those ubiquitous design elements. They are so commonly used that WordPress again has a special template tag for including them into your theme: <?php get_footer(); ?> This function will accept only one parameter, a string, which works like the sidebar function. Used without a parameter it will fetch the footer.php file and insert it. When used with a parameter like so… <?php get_footer("mini"); ?> <?php get_footer("mega"); ?> …the get_footer() template tag will retrieve the theme files “footer-mini.php” and “footer-mega.php,” respectively. 3.8.2 The wp_footer() Hook Remember the wp_head() hook? Well, the wp_footer() hook is exactly like that, only used down in the footer instead. It tells WordPress, “the footer is right here.” All by itself, it doesn’t do anything, it’s just a generic hook that can be used to which scripts and other functionality may be attached. For example, it is fairly common practice to load HTML-dependent JavaScript files from within the footer instead of the header. The location of the wp_footer() hook within your footer.php file will determine where the JavaScript is displayed in the source code. Thus, a good place for this hook is just before the closing <body> tag. <?php wp_footer(); ?></body> 82 Mini footer Mega footer JeCampana.com Just a thin black bar with a copyright and a small illustration. Even that small bit of text could be kept dynamic: &copy; <?php echo date("Y"); bloginfo('name'); ?> YoDiv.com Enormous section of content displayed with a clever “underground” design. This could have been accomplished any number of ways, but probably most practically by using the Links area in the Admin and using the wp_ list_bookmarks to generate the different categories of links. 83 3.8.3 Mini Footers / Mega Footers Like your sidebar, the design of your footer should serve the needs of your site and it’s audience. If you don’t need the room in your footer, no need to junk it up with unnecessary stuff. At the same time you shouldn’t be afraid to do something interesting or innovative if you have appropriate content and the desire to do so. 3.9.1 Theme Functions WordPress themes can include a special file, functions.php, which gives you a lot of control and power over things that happen in your theme. Think of it like a file that can do anything a plugin can do, without needing a plugin. Neat eh? This allows for a lot of cool theme functionality that was not possible in the days before this file existed. The functions.php file is also beneficial for themes that need to be “bundled” with certain plugins. 3.9.2 Functions are for Specific Themes Because you can accomplish similar things with plugins as you can with custom functions (i.e., the functions.php file), some rational decisions should be made about where to do what. Because the functions contained within the functions.php file reside within the theme folder itself, the code inside it depends on that particular theme being active in order to run. Plugins on the other hand, remain operational (or inoperational, as the case may be) regardless of which theme is active. Thus, don’t put anything in functions.php that is required by multiple themes. Likewise, don’t do anything with a plugin that is only relevant to the current theme. 84 Examples: Hide WordPress upgrade notification bar Use a plugin Add button to Post Editor Use a plugin Load jQuery from Google Use functions.php Replace default Gravatar image Use functions.php In the top two examples, the desired result is related to the Admin area and so has nothing to do with the theme itself. You should use a plugin here, because they are theme-independent and won’t stop working when you change themes. In the bottom two examples, those two things are specific to a theme, and thus should happen in the functions.php for that theme. 3.9.3 Advantage Over Core Hacks In the dark days before functions.php, modifying and customizing WordPress functionality was often a matter of altering “core” files. There are a number of problems with this. First and foremost, you could break something in a pretty substantial way and have no clear path to restored functionality. Equally as important, upgrading WordPress means upgrading core files. As in, overwriting them. You would lose your alteration entirely unless you documented exactly what you did; and even then you would have to trudge through and manually re-implement your changes with every new version of WordPress (and there are plenty, trust us). As you do this, you will also need to account for any changes in the core files and adapt your hack accordingly. A real pain in the keyboard, if you know what we mean. The worst part of this nasty practice is that, after going through a few upgrades, you will probably throw in the towel and stop upgrading 85 to new versions. This of course is bad because it leaves you open to potential vulnerabilities and missing out on the latest and greatest cool features. Fortunately hacking the WordPress core is rarely needed these days because there are so many hooks available to latch onto and literally rewrite content or append new functionality. Up next… Now that we are familiar with the anatomy and basic functionality of a WordPress theme, let’s dig deeper into WordPress and learn as much as we can about theme design and development. Strap yourself in, it’s going to be a wild ride! It may not look like a typical WordPress site, but it is! All the quotes seen in this book are from Quotes on Design. http://quotesondesign.com If You Must… As bad a practice as it is to hack the WordPress core, there may be situations in which doing so is the only way to accomplish your goals (WordPress isn’t all-powerful, after all). If you nd yourself contemplating a little core hacking, be sure to check out Chapter 5.4.3 – Hacking the WordPress Core – for some helpful tips. 86 My rates are as follows: $50/hour $75/hour if you watch $100/hour if you help – CLASSIC AUTOBODY SIGN . '/inc/special-search-form.php'); ?> Where might you use this? • On the 404 page (404.php) • In the “else” part of The Loop • In the sidebar 3.7.3 Alternatives to WordPress Search The. that the WordPress built-in search kind of sucks. It lists things in chronological order based on whether or not it found any of your search 80 terms. When searching for your query, WordPress. site- specific search engines into any site. It’s easy and super-awesome. Search API Plugin http://digwp.com/u/54 This plugin provides a far more powerful searching system than the default WordPress