Add custom fields and background editing functional areas to articles in WordPress, _PHP tutorial

Add custom fields and background editing function areas to articles in WordPress,

add_post_meta
The add_post_meta function is a function in WordPress used to add custom field values ​​to posts or pages,
Its usage is the same as using the custom column panel to add custom field values ​​to the article in the article writing interface when writing an article.

add_post_meta function description
Add custom fields to articles.
Common uses include: article views, like buttons, seo plug-ins and other commonly used plug-ins are the custom field functions used.

Detailed explanation of parameters

add_post_meta($post_id, $meta_key, $meta_value,$unique);

$post_id
The ID value of the post or page to which the custom field is to be added
$meta_key
Key value (name) of custom field
$meta_value
Custom field value
$unique
If there is already a custom field with the same name, whether to add a custom field with the same name repeatedly, true means not allowed, false means allowed
Function usage examples

//为ID为1的文章添加_postviews自定义字段，值为99
add_post_meta(1, "_postviews", "99");
var_dump(get_post_meta(1));echo"<br />";
//为ID为1的文章添加_postviews自定义字段，值为999，并允许重复自定义字段名称
add_post_meta(1, "_postviews", 999,false);
var_dump(get_post_meta(1));echo"<br />";

Demo effect:

array(1) {
 ["_postviews"]=>
 array(1) {
  [0]=>
  string(2) "99"
 }
}

array(1) {
 ["_postviews"]=>
 array(2) {
  [0]=>
  string(2) "99"
  [1]=>
  string(3) "999"
 }
}


//不允许重复自定义字段的代码
add_post_meta(1, "_postviews", "996",true);
var_dump(get_post_meta(1));echo"<br />";
add_post_meta(1, "_postviews", "997",true);
var_dump(get_post_meta(1));echo"<br />";
array(1) {
 ["_postviews"]=>
 array(1) {
  [0]=>
  string(3) "996"
 }
}


array(1) {
 ["_postviews"]=>
 array(1) {
  [0]=>
  string(3) "996"
 }
}

add_meta_box
add_meta_box is a function used in advanced WordPress. Being able to use this function means that you already understand this world-famous blogging program better than an ordinary blogger. At least you have spent a lot of effort on it. . Being able to use it means that you are now working on a theme, plug-in, or even the WordPress backend.
It seems that we have gone into too much detail. Let's explain how to use this function from an advanced perspective.

add_meta_box function description
The add_meta_box function is a function used to add a set area on pages such as article editing.

Parameter description

<&#63;php
 add_meta_box( $id, $title, $callback, $post_type, $context, $priority, $callback_args );
 &#63;>

$id Set the value of the id attribute in the area in the HTML code
Title name in $title area
$callback adds the display function (callback function) of the setting area
$post_type is displayed in the edit page of post or page
$context sets the display position of the area, main editing area, sidebar, others
$priority sets the priority of area display
$callback_args Additional parameters accepted by the callback function
Usage examples

function add_xz_box (){//添加设置区域的函数
add_meta_box('xz_box_1', 'add_meta_box 测试', 'xz_box_1','post','side','high',array('str1','str2'));
};
//在'add_meta_boxes'挂载 add_xz_box 函数
add_action('add_meta_boxes','add_xz_box');
 
 
function xz_box_1($post,$boxargs){//显示设置区域的回调函数
 echo"add_meta_box 测试";
};

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