Once found, it uses the dropdown's id to set a GET variable to the value currently selected, then it redirects to this the same URL and adds these GET variables. For example, if the id of the dropdown was product_filter, and this had a value set to date, then it would set the GET variable product_filter=date. It's great because it doesn't care about your Wordpess details - all it cares about is the select element.

// A bunch of helper methods for reading GET variables etc from the URL
jQuery.extend({
    urlGetVars : function() {
        var GET = {};
        var tempGET = location.search;
        tempGET = tempGET.replace('?', '').split('&');
        for(var i in tempGET) {
            var someVar = tempGET[i].split('=');
            if (someVar.length == 2) {
                GET[someVar[0]] = someVar[1];
            }
        }
        return GET;
    },
    urlGetVar : function(name) {
        return $.urlGetVars()[name];
    },
    serializeUrlVars : function(obj) {
        var str = [];
        for(var p in obj)
         str.push(encodeURIComponent(p) + "=" + encodeURIComponent(obj[p]));
        return str.join("&");
    },
    currentUrl : function() {
        return window.location.href.slice(0,window.location.href.indexOf('?'));
    }
});

// Adds functionality to filter content using a dropdown
var ContentFilter = function ($) {
    $(document).ready(function() {
        // Return to a scroll position if exists
        var scroll = $.urlGetVar('scroll');
        if (typeof scroll != 'undefined') {
            $(window).scrollTop(scroll);
        }
        // Prepare the filter dropdowns
        $('.content-filter').each(function(){
            var me = $(this);
            // e.g. content-filter-product
            var id = me.attr('id');
            // Refresh with selected filter on change
            var refresh = function() {
                var GET = $.urlGetVars();
                GET[id] = me.val();
                // Save scroll position, return to this position on load
                GET['scroll'] = $(window).scrollTop();
                var newVar = $.currentUrl() + '?' + $.serializeUrlVars(GET);
                window.location = newVar;
            };
            me.change(refresh);
        });
    });
}(jQuery);

现在是 Wordpress 代码.我们真正需要的是生成具有某种 id 的 select 并将类设置为 .content-filter.此代码要求提供类似post"或product"的帖子类型，并生成 select 元素.为方便起见，它然后返回 GET 变量，如果没有设置，则默认为最新".请注意，$fields 数组设置了所有不同的orderby 值喜欢支持.根据您的类型，您始终可以使用 $_GET['product_filter'] 或 $_GET['post_filter'] 在模板中的任何位置访问它.这意味着在任何给定页面上只能存在一个，但您需要这样做 - 否则 jQuery 将不知道该使用哪个.您可以扩展此代码以设置自定义 ID 或您以后喜欢的任何内容.

Now the Wordpress code. All we really need is to generate the select with some kind of id and set the class to .content-filter. This code asks for a post type like 'post' or 'product' and makes the select element. It then returns the GET variable for convenience, and if none is set then it defaults to 'newest'. Notice that the $fields array sets all the different orderby values you'd like to support. You can always access it anywhere in the template with $_GET['product_filter'] or $_GET['post_filter'] depending on what your type is. This means that only one can exist on any given page, but you want that - otherwise jQuery won't know which to use. You can extend this code to set a custom id or anything you like later.

function ak_content_filter($post_type_id = 'post', &$filter_get_value, $echo = TRUE) {
    $dropdown = '<div class="content-filter-wrapper">';
    // The dropdown filter id for this post type
    $filter_id = $post_type_id.'_filter';
    // The actual dropdown
    $dropdown .= '<label for="'. $filter_id .'">Filter</label><select id="'. $filter_id .'" class="content-filter" name="'. $filter_id .'">';
    // The available ways of filtering, to sort you'd need to set that in the WP_Query later
    $fields = array('date' => 'Newest', 'comment_count' => 'Most Popular', 'rand' => 'Random');
    $filter_get_value = isset($_GET[$filter_id]) ? $_GET[$filter_id] : 'newest'; // default is 'newest'
    foreach ($fields as $field_value=>$field_name) {
        $dropdown .= '<option value="'. $field_value .'" '. selected($field_value, $filter_get_value, FALSE) .'>'. $field_name .'</option>';
    }
    $dropdown .= '</select></div>';
    // Print or return
    if ($echo) {
        echo $dropdown;
    } else {
        return $dropdown;
    }
}

现在是有趣的部分 - 将其放在内容页面中.我们所有的工作都会通过一些甜蜜而简短的代码得到回报:

Now the fun part - putting it together in the content page. All our work pays off with some sweet and short code:

// This will fill $product_filter with $_GET['product_filter'] or 'newest' if it doesn't exist
ak_content_filter('product', $product_filter);
$args = array('post_type' => 'product', 'orderby' => $product_filter);
// This is just an example, you can use get_pages or whatever supports orderby
$loop = new WP_Query( $args );

// OR, to avoid printing:
$dropdown = ak_content_filter('product', $product_filter, FALSE);
// ... some code ...
echo $dropdown;

我使用了自定义帖子类型产品"，但如果您使用的是帖子"，只需将其替换即可.如果他们还没有的话，有人可能应该把它变成一个插件:P

I used the custom post type 'product', but if you're using 'post' just replace that. Someone should probably make this into a plugin if they haven't already :P

这篇关于使用下拉菜单动态过滤 Wordpress 帖子(使用 php 和 ajax)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！