设置文章特色图像对于 WordPress 用户应该都不陌生吧,就是文章的缩略图,目前几乎所有的国内 WordPress 主题,文章缩略图都是按照:特色图像》文章内第一张图片》默认图片,这个顺序进行显示。
但并不是每篇文章内的第一张图片都能作为缩略图进行完美显示,所以很多时候我们都需要单独设置文章特色图像,以达到最好的显示效果。
特别在新搭建 WordPress 网站的时候,往往可能需要频繁的设置文章特色图像,functions.php 添加以下代码:
/**
* WordPress 后台文章列表设置文章特色图片(缩略图)集成版
* Plugin Name: Easy Thumbnail Switcher
*/
class doocii_Easy_Thumbnail_Switcher {
public $add_new_str;
public $change_str;
public $remove_str;
public $upload_title;
public $upload_add;
public $confirm_str;
public function __construct() {
$this->add_new_str = __( '添加');
$this->change_str = __( '更改');
$this->remove_str = __( '移除');
$this->upload_title = __( '上传特色图片');
$this->upload_add = __( '确定');
$this->confirm_str = __( '你确定?');
add_filter( 'manage_posts_columns', array( $this, 'add_column' ) );
add_action( 'manage_posts_custom_column', array( $this, 'thumb_column' ), 10, 2 );
add_action( 'admin_footer', array( $this, 'add_nonce' ) );
add_action( 'admin_enqueue_scripts', array( $this, 'scripts' ) );
add_action( 'wp_ajax_ts_ets_update', array( $this, 'update' ) );
add_action( 'wp_ajax_ts_ets_remove', array( $this, 'remove' ) );
add_image_size( 'ts-ets-thumb', 75, 75, array( 'center', 'center' ) );
}
/**
* 安全检查
*/
public function add_nonce() {
global $pagenow;
if( $pagenow !== 'edit.php' ) {
return;
}
wp_nonce_field( 'ts_ets_nonce', 'ts_ets_nonce' );
}
/**
* 加载脚本
*/
public function scripts( $pagenow ) {
if( $pagenow !== 'edit.php' ) {
return;
}
wp_enqueue_media();
wp_enqueue_script( 'doocii-ets-js', get_template_directory_uri() . '/js/script.js', array( 'jquery', 'media-upload', 'thickbox' ), '1.0', true );
wp_localize_script( 'doocii-ets-js', 'ets_strings', array(
'upload_title' => $this->upload_title,
'upload_add' => $this->upload_add,
'confirm' => $this->confirm_str,
) );
}
/**
* The action which is added to the post row actions
*/
public function add_column( $columns ) {
$columns['ts-ets-option'] = __( '缩略图');
return $columns;
}
/**
* 显示列
*/
public function thumb_column( $column, $id ) {
switch( $column ) {
case 'ts-ets-option':
if( has_post_thumbnail() ) {
the_post_thumbnail( 'ts-ets-thumb' );
echo '<br>';
echo sprintf( '<button type="button" class="button-primary ts-ets-add" data-id="%s">%s</button>', esc_attr( $id ), $this->change_str );
echo sprintf( ' <button type="button" class="button-secondary ts-ets-remove" data-id="%s">%s</button>', esc_attr( $id ), $this->remove_str );
} else {
echo sprintf( '<button type="button" class="button-primary ts-ets-add" data-id="%s">%s</button>', esc_attr( $id ), $this->add_new_str );
}
break;
}
}
/**
* AJAX保存更新缩略图
*/
public function update() {
// 检查是否所有需要的数据都设置与否
if( !isset( $_POST['nonce'] ) || !isset( $_POST['post_id'] ) || !isset( $_POST['thumb_id'] ) ) {
wp_die();
}
//验证
if( !wp_verify_nonce( $_POST['nonce'], 'ts_ets_nonce' ) ) {
wp_die();
}
$id = $_POST['post_id'];
$thumb_id = $_POST['thumb_id'];
set_post_thumbnail( $id, $thumb_id );
echo wp_get_attachment_image( $thumb_id, 'ts-ets-thumb' );
echo '<br>';
echo sprintf( '<button type="button" class="button-primary ts-ets-add" data-id="%s">%s</button>', esc_attr( $id ), $this->change_str );
echo sprintf( ' <button type="button" class="button-secondary ts-ets-remove" data-id="%s">%s</button>', esc_attr( $id ), $this->remove_str );
wp_die();
}
/**
* AJAX回调后删除缩略图
*/
public function remove() {
// Check if all required data are set or not
if( !isset( $_POST['nonce'] ) || !isset( $_POST['post_id'] ) ) {
wp_die();
}
// Verify nonce
if( !wp_verify_nonce( $_POST['nonce'], 'ts_ets_nonce' ) ) {
wp_die();
}
$id = $_POST['post_id'];
delete_post_thumbnail( $id );
echo sprintf( '<button type="button" class="button-primary ts-ets-add" data-id="%s">%s</button>', esc_attr( $id ), $this->add_new_str );
wp_die();
}
}
new doocii_Easy_Thumbnail_Switcher();
以下代码保存为 script.js,保存至 主题名/js 目录下
(function($) {
"use strict";
if( typeof ts_ets === 'undefined' ) {
window.ts_ets = {};
ts_ets.upload_frame = false;
}
$(document).on( 'click', 'button.ts-ets-remove', function() {
ts_ets.tmp_id = $(this).data('id');
ts_ets.tmp_parent = $(this).closest('td.ts-ets-option');
if( !confirm( ets_strings.confirm ) ) {
return;
}
$.ajax({
url: ajaxurl,
method: "POST",
data: {
action: 'ts_ets_remove',
nonce: $('#ts_ets_nonce').val(),
post_id: ts_ets.tmp_id
},
success: function( data ) {
if( data != '' ) {
ts_ets.tmp_parent.html( data );
}
}
});
});
$(document).ready(function() {
ts_ets.upload_frame = wp.media({
title: ets_strings.upload_title,
button: {
text: ets_strings.upload_add,
},
multiple: false
});
ts_ets.upload_frame.on( 'select', function() {
ts_ets.selection = ts_ets.upload_frame.state().get('selection');
ts_ets.selection.map( function( attachment ) {
if( attachment.id ) {
$.ajax({
url: ajaxurl,
method: "POST",
data: {
action: 'ts_ets_update',
nonce: $('#ts_ets_nonce').val(),
post_id: ts_ets.tmp_id,
thumb_id: attachment.id
},
success: function( data ) {
if( data != '' ) {
ts_ets.tmp_parent.html( data );
}
}
});
}
});
});
});
$(document).on( 'click', 'button.ts-ets-add', function(e) {
e.preventDefault();
ts_ets.tmp_id = $(this).data('id');
ts_ets.tmp_parent = $(this).closest('td.ts-ets-option');
if( ts_ets.upload_frame ) {
ts_ets.upload_frame.open();
}
});
})(jQuery);
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