WordPress WP_Widget类

WP_Widget类是WordPress小工具的基类,我们要实现自己的侧边栏小工具,就要基础WP_Widget类,然后实现WP_Widget类的方法。
下面是WP_Widget的源码:

' . __('There are no options for this widget.') . '

'; return 'noform'; } // Functions you'll need to call. /** * PHP5 constructor. * * @since 2.8.0 * @access public * * @param string $id_base Optional Base ID for the widget, lowercase and unique. If left empty, * a portion of the widget's class name will be used Has to be unique. * @param string $name Name for the widget displayed on the configuration page. * @param array $widget_options Optional. Widget options. See wp_register_sidebar_widget() for information * on accepted arguments. Default empty array. * @param array $control_options Optional. Widget control options. See wp_register_widget_control() for * information on accepted arguments. Default empty array. */ public function __construct( $id_base, $name, $widget_options = array(), $control_options = array() ) { $this->id_base = empty($id_base) ? preg_replace( '/(wp_)?widget_/', '', strtolower(get_class($this)) ) : strtolower($id_base); $this->name = $name; $this->option_name = 'widget_' . $this->id_base; $this->widget_options = wp_parse_args( $widget_options, array( 'classname' => $this->option_name, 'customize_selective_refresh' => false ) ); $this->control_options = wp_parse_args( $control_options, array( 'id_base' => $this->id_base ) ); } /** * PHP4 constructor. * * @since 2.8.0 * @access public * * @see __construct() * * @param string $id_base Optional Base ID for the widget, lowercase and unique. If left empty, * a portion of the widget's class name will be used Has to be unique. * @param string $name Name for the widget displayed on the configuration page. * @param array $widget_options Optional. Widget options. See wp_register_sidebar_widget() for information * on accepted arguments. Default empty array. * @param array $control_options Optional. Widget control options. See wp_register_widget_control() for * information on accepted arguments. Default empty array. */ public function WP_Widget( $id_base, $name, $widget_options = array(), $control_options = array() ) { _deprecated_constructor( 'WP_Widget', '4.3.0', get_class( $this ) ); WP_Widget::__construct( $id_base, $name, $widget_options, $control_options ); } /** * Constructs name attributes for use in form() fields * * This function should be used in form() methods to create name attributes for fields * to be saved by update() * * @since 2.8.0 * @since 4.4.0 Array format field names are now accepted. * @access public * * @param string $field_name Field name * @return string Name attribute for $field_name */ public function get_field_name($field_name) { if ( false === $pos = strpos( $field_name, '[' ) ) { return 'widget-' . $this->id_base . '[' . $this->number . '][' . $field_name . ']'; } else { return 'widget-' . $this->id_base . '[' . $this->number . '][' . substr_replace( $field_name, '][', $pos, strlen( '[' ) ); } } /** * Constructs id attributes for use in WP_Widget::form() fields. * * This function should be used in form() methods to create id attributes * for fields to be saved by WP_Widget::update(). * * @since 2.8.0 * @since 4.4.0 Array format field IDs are now accepted. * @access public * * @param string $field_name Field name. * @return string ID attribute for `$field_name`. */ public function get_field_id( $field_name ) { return 'widget-' . $this->id_base . '-' . $this->number . '-' . trim( str_replace( array( '[]', '[', ']' ), array( '', '-', '' ), $field_name ), '-' ); } /** * Register all widget instances of this widget class. * * @since 2.8.0 * @access public */ public function _register() { $settings = $this->get_settings(); $empty = true; // When $settings is an array-like object, get an intrinsic array for use with array_keys(). if ( $settings instanceof ArrayObject || $settings instanceof ArrayIterator ) { $settings = $settings->getArrayCopy(); } if ( is_array( $settings ) ) { foreach ( array_keys( $settings ) as $number ) { if ( is_numeric( $number ) ) { $this->_set( $number ); $this->_register_one( $number ); $empty = false; } } } if ( $empty ) { // If there are none, we register the widget's existence with a generic template. $this->_set( 1 ); $this->_register_one(); } } /** * Sets the internal order number for the widget instance. * * @since 2.8.0 * @access public * * @param int $number The unique order number of this widget instance compared to other * instances of the same class. */ public function _set($number) { $this->number = $number; $this->id = $this->id_base . '-' . $number; } /** * Retrieves the widget display callback. * * @since 2.8.0 * @access public * * @return callable Display callback. */ public function _get_display_callback() { return array($this, 'display_callback'); } /** * Retrieves the widget update callback. * * @since 2.8.0 * @access public * * @return callable Update callback. */ public function _get_update_callback() { return array($this, 'update_callback'); } /** * Retrieves the form callback. * * @since 2.8.0 * @access public * * @return callable Form callback. */ public function _get_form_callback() { return array($this, 'form_callback'); } /** * Determines whether the current request is inside the Customizer preview. * * If true -- the current request is inside the Customizer preview, then * the object cache gets suspended and widgets should check this to decide * whether they should store anything persistently to the object cache, * to transients, or anywhere else. * * @since 3.9.0 * @access public * * @global WP_Customize_Manager $wp_customize * * @return bool True if within the Customizer preview, false if not. */ public function is_preview() { global $wp_customize; return ( isset( $wp_customize ) && $wp_customize->is_preview() ) ; } /** * Generates the actual widget content (Do NOT override). * * Finds the instance and calls WP_Widget::widget(). * * @since 2.8.0 * @access public * * @param array $args Display arguments. See WP_Widget::widget() for information * on accepted arguments. * @param int|array $widget_args { * Optional. Internal order number of the widget instance, or array of multi-widget arguments. * Default 1. * * @type int $number Number increment used for multiples of the same widget. * } */ public function display_callback( $args, $widget_args = 1 ) { if ( is_numeric( $widget_args ) ) { $widget_args = array( 'number' => $widget_args ); } $widget_args = wp_parse_args( $widget_args, array( 'number' => -1 ) ); $this->_set( $widget_args['number'] ); $instances = $this->get_settings(); if ( array_key_exists( $this->number, $instances ) ) { $instance = $instances[ $this->number ]; /** * Filter the settings for a particular widget instance. * * Returning false will effectively short-circuit display of the widget. * * @since 2.8.0 * * @param array $instance The current widget instance's settings. * @param WP_Widget $this The current widget instance. * @param array $args An array of default widget arguments. */ $instance = apply_filters( 'widget_display_callback', $instance, $this, $args ); if ( false === $instance ) { return; } $was_cache_addition_suspended = wp_suspend_cache_addition(); if ( $this->is_preview() && ! $was_cache_addition_suspended ) { wp_suspend_cache_addition( true ); } $this->widget( $args, $instance ); if ( $this->is_preview() ) { wp_suspend_cache_addition( $was_cache_addition_suspended ); } } } /** * Handles changed settings (Do NOT override). * * @since 2.8.0 * @access public * * @global array $wp_registered_widgets * * @param int $deprecated Not used. */ public function update_callback( $deprecated = 1 ) { global $wp_registered_widgets; $all_instances = $this->get_settings(); // We need to update the data if ( $this->updated ) return; if ( isset($_POST['delete_widget']) && $_POST['delete_widget'] ) { // Delete the settings for this instance of the widget if ( isset($_POST['the-widget-id']) ) $del_id = $_POST['the-widget-id']; else return; if ( isset($wp_registered_widgets[$del_id]['params'][0]['number']) ) { $number = $wp_registered_widgets[$del_id]['params'][0]['number']; if ( $this->id_base . '-' . $number == $del_id ) unset($all_instances[$number]); } } else { if ( isset($_POST['widget-' . $this->id_base]) && is_array($_POST['widget-' . $this->id_base]) ) { $settings = $_POST['widget-' . $this->id_base]; } elseif ( isset($_POST['id_base']) && $_POST['id_base'] == $this->id_base ) { $num = $_POST['multi_number'] ? (int) $_POST['multi_number'] : (int) $_POST['widget_number']; $settings = array( $num => array() ); } else { return; } foreach ( $settings as $number => $new_instance ) { $new_instance = stripslashes_deep($new_instance); $this->_set($number); $old_instance = isset($all_instances[$number]) ? $all_instances[$number] : array(); $was_cache_addition_suspended = wp_suspend_cache_addition(); if ( $this->is_preview() && ! $was_cache_addition_suspended ) { wp_suspend_cache_addition( true ); } $instance = $this->update( $new_instance, $old_instance ); if ( $this->is_preview() ) { wp_suspend_cache_addition( $was_cache_addition_suspended ); } /** * Filter a widget's settings before saving. * * Returning false will effectively short-circuit the widget's ability * to update settings. * * @since 2.8.0 * * @param array $instance The current widget instance's settings. * @param array $new_instance Array of new widget settings. * @param array $old_instance Array of old widget settings. * @param WP_Widget $this The current widget instance. */ $instance = apply_filters( 'widget_update_callback', $instance, $new_instance, $old_instance, $this ); if ( false !== $instance ) { $all_instances[$number] = $instance; } break; // run only once } } $this->save_settings($all_instances); $this->updated = true; } /** * Generates the widget control form (Do NOT override). * * @since 2.8.0 * @access public * * @param int|array $widget_args { * Optional. Internal order number of the widget instance, or array of multi-widget arguments. * Default 1. * * @type int $number Number increment used for multiples of the same widget. * } * @return string|null */ public function form_callback( $widget_args = 1 ) { if ( is_numeric($widget_args) ) $widget_args = array( 'number' => $widget_args ); $widget_args = wp_parse_args( $widget_args, array( 'number' => -1 ) ); $all_instances = $this->get_settings(); if ( -1 == $widget_args['number'] ) { // We echo out a form where 'number' can be set later $this->_set('__i__'); $instance = array(); } else { $this->_set($widget_args['number']); $instance = $all_instances[ $widget_args['number'] ]; } /** * Filter the widget instance's settings before displaying the control form. * * Returning false effectively short-circuits display of the control form. * * @since 2.8.0 * * @param array $instance The current widget instance's settings. * @param WP_Widget $this The current widget instance. */ $instance = apply_filters( 'widget_form_callback', $instance, $this ); $return = null; if ( false !== $instance ) { $return = $this->form($instance); /** * Fires at the end of the widget control form. * * Use this hook to add extra fields to the widget form. The hook * is only fired if the value passed to the 'widget_form_callback' * hook is not false. * * Note: If the widget has no form, the text echoed from the default * form method can be hidden using CSS. * * @since 2.8.0 * * @param WP_Widget $this The widget instance, passed by reference. * @param null $return Return null if new fields are added. * @param array $instance An array of the widget's settings. */ do_action_ref_array( 'in_widget_form', array( &$this, &$return, $instance ) ); } return $return; } /** * Registers an instance of the widget class. * * @since 2.8.0 * @access public * * @param integer $number Optional. The unique order number of this widget instance * compared to other instances of the same class. Default -1. */ public function _register_one( $number = -1 ) { wp_register_sidebar_widget( $this->id, $this->name, $this->_get_display_callback(), $this->widget_options, array( 'number' => $number ) ); _register_widget_update_callback( $this->id_base, $this->_get_update_callback(), $this->control_options, array( 'number' => -1 ) ); _register_widget_form_callback( $this->id, $this->name, $this->_get_form_callback(), $this->control_options, array( 'number' => $number ) ); } /** * Saves the settings for all instances of the widget class. * * @since 2.8.0 * @access public * * @param array $settings Multi-dimensional array of widget instance settings. */ public function save_settings( $settings ) { $settings['_multiwidget'] = 1; update_option( $this->option_name, $settings ); } /** * Retrieves the settings for all instances of the widget class. * * @since 2.8.0 * @access public * * @return array Multi-dimensional array of widget instance settings. */ public function get_settings() { $settings = get_option( $this->option_name ); if ( false === $settings ) { if ( isset( $this->alt_option_name ) ) { $settings = get_option( $this->alt_option_name ); } else { // Save an option so it can be autoloaded next time. $this->save_settings( array() ); } } if ( ! is_array( $settings ) && ! ( $settings instanceof ArrayObject || $settings instanceof ArrayIterator ) ) { $settings = array(); } if ( ! empty( $settings ) && ! isset( $settings['_multiwidget'] ) ) { // Old format, convert if single widget. $settings = wp_convert_widget_settings( $this->id_base, $this->option_name, $settings ); } unset( $settings['_multiwidget'], $settings['__i__'] ); return $settings; } }
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