So you have a wordpress blog and you (or your client) want the wp-admin to use an SSL certificate, sounds great! However, any AJAX you use in your site has broken. I spent a while googling this issue when it happened to me and found a really easy fix; you need to change the variables in the get_admin_url() function to force the AJAX requestion to use http instead of https. Change it to look like:

get_admin_url(null,'','http');

I hope this helps a lot of people!

I have decided to explain how to use the WordPress Settings API after having pulled out most my hair whilst googling for a easy to understand explanation.

The reason I wanted to use the WordPress Settings API was because whilst making plugins, I found that my code for my options page was getting a little messy. I had also read, that if you use the Settings API, you don’t ever have to use the update_option() function.

Finally, being a WordPress API, I would like to think that this make my plugins a little more future-proof against wordpress upgrades.

Please note that in this walkthrough I am storing the options into an array.

So this is how it is done:

add_action('admin_menu', 'create_plugin_options_page');
add_action('admin_init', 'register_and_build_plugin_options');

function create_plugin_options_page() {
  //register the menu item
  add_menu_page('Plugins Option', 'Plugin Options', 'administrator', 'option-page-name', 'plugin_options_page');
}

function register_and_build_plugin_options(){
  //register the option value you will be using.
  //N.B. the second parameter must be the same as what you have named the option in your plugin activation
  register_setting('settings_option','plugin_settings', 'validate_option');
  add_settings_section('first_setting_section', 'Settings Section 1','section1_callback','option-page1');
  add_settings_field('setting_text','Text Field: ','text_field','option-page1','first_setting_section');
}

You can have lots of fields in lots of sections. Important things to note when using add_settings_section, add_settings_field, register_setting:

• The 3rd parameter of register_setting is a callback for validation. In the example above, I have a function (shown later) called validate_option which contains any required validation. This field is optional.
• The 4th parameter of add_settings_field must correlate to a 1st parameter of add_settings_section
• The 4th parameter of add_settings_section which should be the same as the 4th parameter of add_settings_field (‘option-page1′) is what you will later use to load this section by using the function do_settings_section();
• The 3rd parameter of add_settings_section is a callback function. It can be a blank function if you want it to be.
• The 3rd parameter of add_settings_field is a callback function that contains the input field that you want.

function text_field(){
	  $optionValue = get_option('plugin_settings');
    $option = "";
    $option .= "";
    echo $option;
}

You must name the field by the option name so it will save correctly, like I have done above with name=\”plugin_settings[text_field]\”.

Now finally, the function that brings it all together:

function plugin_options_page() {
?>
<div id="theme-options-wrap">
<h2>Plugin Title</h2>
<div><form action="options.php" method="post"> 
<p class="submit"><input class="button-primary" type="submit" name="Submit" value="<?php esc_attr_e('Save Changes'); ?>" /></p>

</form></div>
</div>
<div id="theme-options-wrap">
<h2>Plugin Title</h2>
<div><form action="options.php" method="post"> 
<p class="submit"><input class="button-primary" type="submit" name="Submit" value="<?php esc_attr_e('Save Changes'); ?>" /></p>

</form></div>
</div>
<?php
}

function validate_option($option){
    //put any validation on the options here.
    return $option;
}

function section1_callback(){}

function section2_callback(){
	$html = "An example of some text in the callback function";
	echo $html;
}

function text_field(){
	  $optionValue = get_option('plugin_settings');
    $option = "";
    $option .= "
<input id=\"text_field\" type=\"text\" name=\"plugin_settings[text_field]\" value=\"{$optionValue['text_field']}\"?-->";
    echo $option;
}

function select_field(){
    $options = get_option('plugin_settings');
    $items = array("Red", "Green", "Blue", "Orange", "White", "Violet", "Yellow");
    $html = "
    <select id="select_field" name="plugin_settings[select_field]">";
    foreach($items as $item) {
        $selected = ($options['select_field']==$item) ? 'selected="selected"' : ''; $html .= " <option selected="selected" value="$item">$item</option> ";
    }
    $html .= "</select>";
    echo $html;
}
function checkbox_field(){
    $optionValue = get_option('plugin_settings');
    $option = "";
    $option .= " <input type="\"checkbox\"" name="\"plugin_settings[checkbox_field]\"" value="\&quot;1\&quot;" checked="checked" />";
    echo $option;
}
function radio_field(){
    $optionValue = get_option('plugin_settings');
    $option = "";
    $option .= " <input type="\"radio\"" name="\"plugin_settings[radio_field]\"" value="\"value1\"" checked="checked" />Value1 ";
    $option .= " <input type="\"radio\"" name="\"plugin_settings[radio_field]\"" value="\"value2\"" checked="checked" />Value2 ";
    echo $option;
}

This will allow you to have a settings page that looks like:

Quite a Mouthful! However I hope this really helps for people trying to get to grips with API. Admittedly, I have written this partly as a response to lack of documentation on the API!

If you would like more help, I found this documentation helpful: http://www.presscoders.com/wordpress-settings-api-explained/

With WordPress now able to use custom post types, I have asked on forums if anyone new how to filter by more than one taxonomy. I originally tried using

 query_posts('cat=6,5') 

and other similar commands but have no luck.

To resolve this I came up with the following solution:

First I create two custom fields on the page which I named taxonomy1 and taxonomy2.
I then added the following code:

 <?php 
$taxonomy1 = get_post_meta($post->ID, "taxonomy1"); 
$taxonomy2 = get_post_meta($post->ID, "taxonomy2");

//this is an sql query to find all posts containing two taxonomies
$sql_query = "SELECT * FROM (
			SELECT wp_posts.ID FROM `wp_posts` 
				JOIN wp_term_relationships ON wp_posts.ID=wp_term_relationships.object_id
				JOIN wp_terms ON wp_term_relationships.term_taxonomy_id=wp_terms.term_id
					WHERE slug = '".$taxonomy1[0]."' 
			UNION ALL
			SELECT wp_posts.ID FROM `wp_posts` 
				JOIN wp_term_relationships ON wp_posts.ID=wp_term_relationships.object_id
				JOIN wp_terms ON wp_term_relationships.term_taxonomy_id=wp_terms.term_id
					WHERE post_type = 'tiles' AND slug = '".$taxonomy2[0]."'
		) AS results

		GROUP BY results.id HAVING COUNT(*) = 2";
		
	$newresults = $wpdb->get_results($sql_query);			
		
	$ArrayOfIDs = array();
		
	foreach($newresults as $newresult){
		array_push($ArrayOfIDs, $newresult->ID);
	}

	query_posts(array('posts_per_page'=>'900','post_type' => 'tiles','post__in' => $ArrayOfIDs));
?>

The idea behind this code is that the mysql query returns the post IDs of the posts that correspond to the two taxonomy filters and then the foreach loop pushes those into an array of IDs ($ArrayOfIDs) which is then used in the query_post function.

Feedback would be much appreciated on other ways that I could have resolved this issue or also how I could improve this code.