How To Create WordPress Widgets

Written by on Monday 20th April 2009 under WordPress

Wordpress plugins are pieces of addon code that extend the functionality of Wordpress, either behind-the-scenes or extra visual code. Widgets allow these code segments to be quickly and easily added to predefined sidebars on most themes.

This article refers to old versions of WordPress. For an up to date guide for the most recent versions (2.8+) please see this article - How To Create Widgets for WordPress 2.8

Before WordPress version 2.0, these extra visual plugins had to be hand coded into the theme template, so knowledge of PHP was required. In version 2.0 they introduced "Widgets" which wrap around a plugin and allow a non code editing method for incorporating into a theme using sidebars and a drag and drop interface.

This tutorial covers creating a Widget, creating a plugin widget, adding sidebars to a theme, and upgrading a non-widget plugin.

Creating a Simple WordPress Plugin

You can use this as a code snippet for your projects. I am going to create a simple plugin that does nothing but display "Hello World". I'll leave the actual functionality of the plugin to you  ;) 

Create a new php file in your plugin directory called my-hello-world.php, and type the following plugin code:

  1. <?php
  2. /*
  3. Plugin Name: Hello World
  4. Plugin URI: http://timtrott.co.uk/
  5. Description: Sample Hello World Plugin
  6. Author: Tim Trott
  7. Version: 1
  8. Author URI: http://timtrott.co.uk/
  9. */
  10.  
  11. function sampleHelloWorld()
  12. {
  13.   echo"<h2>Hello World</h2>";
  14. }
  15. ?>
  16.  

The lines inside /* and */ are used by WordPress to find out about the plugin. We have one function called sampleHelloWorld which does exactly that.

Now, traditionally we would have had to open up the sidebar of the theme you are using, find the location of where you want the Hello World displayed, and hard code the function in. Upload to the server and test. If for some reason there is a problem with your plugin (or a third party plugin) then your site would almost certainly stop working. Changing the location from the left to the right sidebar means editing both files accordingly. This isn't very good.

Widgets

Widgets take away the need for editing the sidebar files of a theme and allow for a drag and drop interface in the admin panel. Let's have a look at how we can widget enable our plugin.

Open up the Hello World plugin file again and add these lines:

  1.  
  2. function widget_myHelloWorld(){
  3. ?>
  4.   <h2 class="widgettitle">My Widget Title</h2>
  5.   <?php sampleHelloWorld();?>
  6. <?php
  7. }
  8.  
  9. function myHelloWorld_init()
  10. {
  11.   register_sidebar_widget(__('Hello World'),'widget_myHelloWorld');    
  12. }
  13. add_action("plugins_loaded","myHelloWorld_init");
  14.  

The first function here is what will be displayed on the sidebar when its set-up correctly. Notice that we are calling on our old function. This is upgrading the existing plugin to be widget enabled. You can if you like replace the function call with the function statements and combine the two functions.

The second function is called by WordPress when the plugin is activated. It calls a WordPress function that will register a new widget which will be called "Hello World" which will call our new widget function.

Add action just tells WordPress to call myHelloWorld_init when the plugin is loaded.

Enhancements for Theme Compatibility

While this widget will function fine, we can make some improvements to enable greater theme compatibility - not everyone uses the same themes as you test on.

WordPress will pass parameters to your widget, which contain information about the sidebar and the CSS classes. We should process these parameters and output the correct tags, or you risk breaking some themes.

The first thing we need to do is change our sampleHelloWorld function so that it will accept parameters, then to process these parameters into variables. This is done using the extract function.

  1.  
  2. function widget_myHelloWorld($args){
  3.   extract($args);
  4. ?>
  5.   <h2 class="widgettitle">My Widget Title</h2>
  6.   <?php sampleHelloWorld();?>
  7. <?php
  8. }

These two lines will allow us to reference some variables and output correct html structure for the theme being used. The most important variables are before_widget, after_widget, before_title and after_title. Previously we have surrounded the widget title with a hard coded H2 tag with a css class widgettitle, but many themes do not support these tags. They may use a div, or a h1 or a span, so we need our widget to be flexible.

  1.  
  2. function widget_myHelloWorld($args){
  3.   extract($args);
  4.   echo$before_widget;
  5.   echo$before_title;?>My Widget Title<?php echo$after_title;
  6.   sampleHelloWorld();
  7.   echo$after_widget;
  8. }

These changes will allow our plugin to use the same tags as the theme author informs us we need to use, and will allow your widget to look the same as the other widgets in the sidebar.

To configure these options inside a theme, please see the section below on theme support.

Complete Plugin:

  1. <?php
  2. /*
  3. Plugin Name: Hello World
  4. Plugin URI: http://timtrott.co.uk/
  5. Description: Sample Hello World Plugin
  6. Author: Tim Trott
  7. Version: 1
  8. Author URI: http://timtrott.co.uk/
  9. */
  10.  
  11. function sampleHelloWorld()
  12. {
  13.   echo"<h2>Hello World</h2>";
  14. }
  15.  
  16. function widget_myHelloWorld($args){
  17.   extract($args);
  18.   echo$before_widget;
  19.   echo$before_title;?>My Widget Title<?php echo$after_title;
  20.   sampleHelloWorld();
  21.   echo$after_widget;
  22. }
  23.  
  24. function myHelloWorld_init()
  25. {
  26.   register_sidebar_widget(__('Hello World'),'widget_myHelloWorld');    
  27. }
  28. add_action("plugins_loaded","myHelloWorld_init");
  29. ?>
  30.  

Testing your Plugin

If you check your plugins page now, you should now have a new plugin listed called Hello World which you can activate. On the Presentation tab, select widgets, and you should see your new widget available to be dragged onto a sidebar. Save your changes and admire your new work.

Wordpress Widget listed as installed

Stop! My Theme Doesn't Support Widgets!

If your theme does not have widget enabled sidebars, this little tutorial will help make it widget enabled. I am using a very basic sidebar theme, most sidebars are a little more complex than this.

  1.      
  2. <div id="sidebar">
  3.   <ul>
  4.     <?phpif(!function_exists('dynamic_sidebar')||!dynamic_sidebar()):?>
  5.       <?php wp_list_pages('title_li=<h2>Pages</h2>');?><br/>
  6.       <li><h2>Archives</h2>
  7.         <ul>
  8.           <?php wp_get_archives('type=monthly');?>
  9.         </ul>
  10.       </li>
  11.       <?php wp_list_categories('show_count=1&amp;title_li=<h2>Categories</h2>');?>
  12.     <?phpendif;?>
  13.   </ul>
  14. </div>
  15.  

The first of these lines does an if else statement, if we have a sidebar function call it otherwise we do the existing hard coded sidebar.

The second line (endif) tells the if statement where the hard coded sidebar ends. Anything between the first and second lines will be shown if widgets are disabled or no widgets are assigned to the sidebar.

Before you can add a widget to this sidebar, we need to make WordPress aware of it by registering it.

Open, or create, functions.php in your theme folder, and find (or add) a line like this:

  1.  
  2. <?php
  3. if(function_exists('register_sidebars'))
  4.     register_sidebars(1);
  5. ?>
  6.  

Where the parameter to register_sidebars is the number of sidebars defined in your theme. You can have any number of sidebars. Now you will be able to add widgets to your sidebar.

Should you wish to configure the elements that will appear before and after a widget, or the tags that a widget title will appear in, you can setup the options array and pass it to the register_sidebar function.

  1. register_sidebar(array(
  2. 'before_widget'=>'<li>',
  3. 'after_widget'=>'</li>',
  4. 'before_title'=>'<div class="sidebar_title">',
  5. 'after_title'=>'</div>',
  6. ));

This will cause the widget to be contained within <li></li> tags and the widget title will be in a div with the css class sidebar_title.

As with most programming and development, there are a number of different methods of obtaining the same results, the techniques listed here are just what works for me.

You may also be interested in reading how to create control panels for your widgets.

96 Responses to “How To Create WordPress Widgets”

  1. donsays:

    Thx!! A nice and easy to follow explanation!

  2. McLartysays:

    Thanks for the great &quot;hello-world&quot; ...I&squot;m just getting started on a plugin!

    got any good links to the next steps? Eg. Calling a flash movie or creating options inside of WordPress for the plug-in?

  3. thanks for you information, this is what i&squot;m looking for... great!

  4. Fareehasays:

    Thanks a bunch for the help.

  5. chatsays:

    thanks for all..

  6. Anonymoussays:

    Really Nice guide to aadd widgets

  7. [...] perusing the WordPress Codex and reading a nice tutorial on creating WordPress widgets that AzuliaDesigns put together, I finally managed to build a working plugin.  The options are exactly [...]

  8. Awshaalsays:

    Thank you so much, such wonderful article.. A++++

  9. Great article, thanks! I've already written plugins but never before a widget. This and your post about how to create control panels for widgets are very useful.

  10. Ranasays:

    Very nice article. Thanks

  11. excellent man! very very very helpful thanks!

  12. uhhh..... i don't get it! It looks to complicated! I thought it would be easy but i guess not..... i was planning on making a widget but now i guess not....  :( 

  13. Jeff R.says:

    I am a little confused by this line;

    &lt?php echo $after_title;

    Is that supposed to be an actual less than bracket, making an opening php tag?

    And, I thought when I started reading this that the Hello World example was just to show you the initial step. What is the purpose of it being called later in the function? I thought for an instant maybe we were supposed to put HTML in there, but you have the widget tags to use what the user theme has already...

    Confused....

  14. You are correct about the php tag, it got converted to html chars along the way  :( 
    Not sure quite what you mean about calling the function? I guess your referring to the call to sampleHelloWorld() from within widget_myHelloWorld($args)? This is just to keep the different sections code separate. You can replace sampleHelloWorld() with whatever you wish.

    HTH

  15. Björnsays:

    Thanx a lot for this nice tutorial ... !!!

    Merry Christmas from Germany...

  16. Phoenixsays:

    Hello sir, i have a question. How can i create a title field for the widget so the user can rename it with whatever they like. I really blind about php and WordPress coding. So could you tell me the code and where to place it. Don't worry i can figure it out. Thanks:).

  17. Davissays:

    I dont get any of the mubble jummble! please help me in a simple way!!!

  18. gerceksays:

    better than wordpress documentation. thanks.

  19. Abisays:

    What a simple solution to my problem. I do not know php but is right away going to try this simple methid to make extra widgets for my blog.
    Thanks!

  20. Nice article. It tells exactly what I need to do.

  21. Great article! I found it very straightforward and helpful.

  22. Aakashsays:

    Thanks very much. This is the thing i want !

  23. Jamessays:

    I just created a Google Translate widget for my blog and it only took a few minutes thanks to your introduction. Thanks!

  24. Thanks really helpful to create a plugin for wordpress..thanks lot..:)

  25. Great article! Really good introduction to widget basics.

    software_developer: thank for the nice link. Really helpful information about widget's setup!

  26. Njualemsays:

    Excellent and Cristal-Clear, I can now get into making widgets for my website.

    Thanks a Million.

  27. Aodsays:

    I'm trying to create a sidebar widget using the code at http://www.stopie6.com/widgets.html (Simple Text Message), but can't work out which code to change in your example, and where to put the code in from the link? How would the php file handle that if statement?

  28. Great article/tutorial

    How about writing about how to make options/settings for a widget. Thar would really be helpful...

  29. jigarsays:

    really verry nice article for beginners and its working fine.... thanks ...

  30. Greate tuto....

    Tks

  31. There are a couple of places where the tag got mixed in with your php.

  32. chocobeesays:

    thanks for the tutorial. do u know any link that teach how to create advance widget?

  33. manitrasays:

    Hello,

    Thanks for this tutorial, it's an excellent starting point.

    Manitra.

  34. Thank for your widget creation step by step explaination,its really awesome,,.

  35. There are <strong> tags in some of the latter examples; looks weird...

  36. Great tutorial to learn first steps. Thank you.

  37. Pravinsays:

    @Uppfinnarn, @Stubbornella: The tags aren't mixed up. They are intented that way.

    Instead of using echo $before_title . 'My Widget Title' . $after_title;

    the author should have used
    echo $before_title;?>My Widget Title<?php echo $after_title;

  38. Pravinsays:

    Oops, the two code lines should be switched.

  39. Derp, they do the same thing genius. Take a look at the generally used wordpress code conventions sometime and you'll see that the way he did it was far from uncommon.

  40. Man... a lifesaver.

    Thanks a lot. This tutorial and the plugin "TS Custom Widgets" (that allows me to select wich widget should show on each page/post) makes wordpress even better.

    Tks a lot

  41. BrandonSchsays:

    Great post , You've really hit the
    nail on the head, I just don't understand why people quite get it.
    I'm not for sure how many people I've talked to concerning this very
    thing in the past month, and they just can't get it.

    , Excellent post!

  42. KreCisays:

    Thanks man! That is so helpful! You will see my new widget plugin released soon!
    Happy New year 2010!  :) 

  43. Thanks for the hello world style example.
    it was the best example i have found yet.

  44. Kaitorasays:

    Your plugin has been a great help for me to learn how to create some wordpress plugins. All of the other tutorials I have seen have not included anything on widgets. Thanks for the wonderful resource

  45. Pinyosays:

    Really excellent tutorial. I appreciate it! Definitely cut my development time in half.

  46. Thank you. This is what I been looking for. lots of articles about creating plugins but few about creating widgets.

  47. This is a very good example. Since I come from a C++ background, it helped e a lot.

    Thanks again!

  48. Conradsays:

    Really appreciate this tutorial. Nicely done - simple, quick and to the point. Nicely done.

  49. Angelikasays:

    This was EXACTLY what I needed. Thank you.

  50. Glennsays:

    Tim,

    Nice tutorial. After doing this over and over again I created to tool to take the tedium out of creating WordPress Widgets. Take a look over at http://www.widgetifyr.com and let me know what you think.

    Glenn

  51. Glennsays:

    Aod,

    You might want to try my tool over at widgetifyr.com. It wraps code into a WordPress widget.

  52. djolesays:

    Very useful article. I am ready to create my personal plugin.
    Thank you.

  53. Dansays:

    Really impressive - very simple but very helpfull. Thanks!

  54. monasays:

    thank.It help me to make my plugin..

  55. Cloversays:

    GEATE ! ! ! !

    Getting this helpful suggestion, I could alive my PHP code as widgets.

    Thank you!!!!

  56. sweet, I have to create my own widget some a site am working on..

  57. cathy2005says:

    Is it possible to add a widget programmatically so that the user does not have to Drag/Drop?

  58. Is it possible to use JavaScript for the Widget?

  59. [...] Great How to Build a Widget Tutorial from LonewolfDesigns [...]

  60. Y.Y.W.says:

    Great tutorial! Thanks for taking the time and post this article. I have bookmarked this post so I can always come back for reference.

    Thanks!

  61. Dhinakransays:

    Nice and smart for the plugin creators

  62. Jeffsays:

    Thank you very much for taking the time to create and share this. With the release of WP 3.0 I'm stepping more into the programing side of WP as I create a custom post type. This is a perfect tutorial for getting me started with Widgets as I wanted a way to display custom post type output in a widget. Thanks!

  63. purwasays:

    wow great! ,this was exactly the solution I was looking for. Thanks alot!

  64. This is shockingly awesome.
    Can't believe it was so easy, I would've started doing this years ago if I'd known!

    Cheers mate.

  65. Prasathsays:

    Thank You very much!!!

  66. Orionsays:

    I've followed the tutorial here, & while the widget appears in the plugins list (which I've activated), my activated plugin doesn't show in the Appearance->Widgets list.

    Might you know why?

    - O8

  67. simple and awesome. Thank you so much for this post  :D 

  68. Deep Csays:

    Simple and Superb !!
    Thanks.

  69. [...] code is based 100% on lonewolfdesigns DevApe Category Widget (0) This entry was posted in Downloads, Uncategorized, Widgets. Bookmark [...]

  70. Tim, with your help I created my first widget ever!

    Thanks a lot man

  71. Thanks for this tutorial, it was very helpful in developing a new widget for BuddyPress!

  72. Thanks for the tutorial, I was trying to find a way to convert mt plugin into a widget for the sidebar.

  73. DavidMsays:

    Thank you much. I'm working on a plugin right now using this base and hopefully will get it released very soon.

  74. Thanks Tim, this just saved me a bunch of time.

  75. relisyssays:

    Tim Trott you are absolutely awesome! I have been trying to get this solution for 4 days straight and no one on irc or anywhere else could help me.

    Many thanks !!!!! Thank you Thank you Thank you.!!

  76. Wingmansays:

    Thank you very much for the post! Simple and clear! Just great!

  77. Shailesays:

    Hi ,

    Thanks to help us.
    It's great and very easy way to make a wedget thanks a lot....:)

  78. This is an excellent article. As someone who has no programming skills, but loads of ideas for wordpress plugins; which is the best place for me to go to be able to hire someone with suitable skills to be able to do the programming for me?

  79. 2012-01-31 TUE 13:40
    First time ever I am leaving a comment!
    Because, this is a pure gold!
    I was able to create my Plug-in in minutes.
    This not only usable, by educational!
    Especially valuable for me was Summary.

    Fantastic! Thank you for your style of presenting!
    As a courtesy to readers, I ran a spell check on my message.

  80. ibnusays:

    thanks, nice info...

    i just learn create plugin that contain widget....

  81. Todd M.says:

    Love this. Thank you for the info.

  82. Raul Singhsays:

    Thanks Buddy,
    A very well written article. Cheers..keep the good work...

  83. satishsays:

    Awesome article.. thanks a lot.

  84. The tutorial is small and best. I have learnt widget creation very quickly from here. Thanks.

  85. alansays:

    Excellent! Thanks for this .. exactly what I was looking for!!

  86. mahmudsays:

    thanx for informative post. i am a newbie to php and do not follow the array, argument etc functions. Please write a tutorial on how to create a simple widget which i can place anywhere in my theme using div tag. Thanks in advance.

  87. Alok Ranjan Dubeysays:

    Thanks,I get a good knowledge about your right instruction.

  88. otenyanosays:

    The plugin works. But I can only use the widget one time. How to make it usable on more sidebars?

  89. Andrewsays:

    Thanks for tutorial! I never attempted to write a plugin before for a fear it would be too complicated.. Now I shall try!  :) 

  90. This article refers to old versions of WordPress. For an up to date guide for the most recent versions (2.8+) please see this article – http://timtrott.co.uk/creating-widgets-wordpress-28/

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