The following tutorial column will introduce how to add Meta Box to WordPress , I hope it will be helpful to friends in need! The way to add Meta Box in WordPress requires the use of add meta boxes Action. This Action allows us to register Meta Box for any article type. In this Action, we need to use the add_meta_box() method to add Meta Box. Related Information. The code is as follows

function add_rating_meta_box($post_type, $post) {   
    // 需要哪些post type添加推薦指數(shù) Meta Box   
    $types = array( 'post', 'page' );   

    foreach ( $types as $type ) {   
        add_meta_box(   
            'rating_meta_box_id', // Meta Box在前臺頁面中的id，可通過JS獲取到該Meta Box   
            '推薦指數(shù)', // 顯示的標題   
            'render_rating_meta_box', // 回調(diào)方法，用于輸出Meta Box的HTML代碼   
            $type, // 在哪個post type頁面添加   
            'side', // 在哪顯示該Meta Box   
            'default' // 優(yōu)先級   
        );   
    }   
}   
add_action( 'add_meta_boxes', 'add_rating_meta_box' );

Here we define the custom field that both Post and Page need to recommend the index in the $types array, and then tell WordPress to use the "render_rating_meta_box" method to render the Meta Box, position In the sidebar. Because there is not much content, the sidebar is sufficient. If there is more content, you can change "side" to "advanced" so that the Meta Box will be rendered in the main content area.

Next let’s see how it is rendered

function render_rating_meta_box( $post ) {   
    // 添加 nonce 項用于后續(xù)的安全檢查   
    wp_nonce_field( 'rating_nonce_action', 'rating_nonce_name' );   

    // 獲取推薦指數(shù)的值   
    $rating_key = 'rating';   
    $rating_value = get_post_meta( $post->ID, $rating_key, true );   
    $rating_value = (int)$rating_value;   

    $html = &#39;<select name="rating_field">&#39;;   
    for ($i = 0; $i <= 10; $i++) {   
        $selected = &#39;&#39;;   
        if ($i == $rating_value) {   
            $selected = &#39;selected="selected"&#39;;   
        }   
        $html .= sprintf(&#39;<option value="%s" %s>%s星</option>&#39;, $i, $selected, $i/2);   
    }   
    $html .= &#39;</select>&#39;;   
    echo $html;   
}

Here we first use wp_nonce_field() to add a nonce field for security checking, then read the value of the recommended index and loop 1 ~10 to output optional values. If it is the same as the recommended index, it will be selected by default. Through the drop-down box, the problem of inconvenient input and inability to verify can be solved. Remember the value of the name attribute of the drop-down box here (rating_field), which will be used to obtain the selected value in the following code.

Finally, when the article is saved, the recommendation index needs to be saved as well

function save_rating_post_data( $post_id ) {   
    // 檢查nonce是否設置   
    if (!isset($_POST['rating_nonce_name'])) {   
        return $post_id;   
    }   
    $nonce = $_POST['rating_nonce_name'];   

    // 驗證nonce是否正確   
    if (!wp_verify_nonce( $nonce, 'rating_nonce_action')) {   
        return $post_id;   
    }   

    // 如果是系統(tǒng)自動保存，則不操作   
    if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {   
        return $post_id;   
    }   

    // 檢查用戶權(quán)限   
    if ($_POST['post_type'] == 'post') {   
        if (!current_user_can('edit_post', $post_id )) {   
            return $post_id;   
        }   
    }   

    $rating_key = 'rating';   
    // 獲取數(shù)據(jù)   
    $rating_value = $_POST['rating_field'];   

    // 更新數(shù)據(jù)   
    update_post_meta( $post_id, $rating_key, $rating_value );   
}   
add_action( 'save_post', 'save_rating_post_data' );

A series of checks are done here, including the nonce check just set, user permissions check, and automatic exclusion Saved condition. Then use the update_post_meta() method to store the data in the database.

At this point, we have completed the modification of the custom field for the recommendation index, and we can easily select the recommendation index of the article.

etc. . .

Careful friends may have discovered that after applying the above three pieces of code, the function can indeed be realized. However, under the default custom column area, you can see that there is a column called "rating", which is the recommendation index we just selected. If you don’t want it to be displayed under the custom column, you can change $rating_key in the above code to start with an underscore, so that WordPress will not display it. Note that there are two places to change.

// 原來的代碼   $rating_key = 'rating';   
// 改后的代碼   $rating_key = '_rating';

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