WordPress选项面板找不到错误'ea_display_section'或函数名称无效

Question

我正在为WordPress背面的主题创建一个选项面板。

目前它只是一个简单的形式。我收到错误警告：call_user_func（）期望参数1是有效的回调，函数

  

'ea_display_section'未找到或无效的函数名称   第1260行的file / template.php

什么错了？这是我的代码

add_action( 'admin_init', 'ea_register_settings' );

function ea_register_settings()
{
    register_setting( 'ea_theme_options', 'ea_theme_options', 'ea_validate_settings' );

    // Add settings section
      add_settings_section( 'ea_text_section', 'Text box Title', 'ea_display_section', 'ea_theme_options.php' );

    // Create textbox field
    $field_args = array(
      'type'      => 'text',
      'id'        => 'ea_textbox',
      'name'      => 'ea_textbox',
      'desc'      => 'Example of textbox description',
      'std'       => '',
      'label_for' => 'ea_textbox',
      'class'     => 'css_class'
    );

    add_settings_field( 'example_textbox', 'Example Textbox', 'ea_display_setting', 'ea_theme_options.php', 'ea_text_section', $field_args );
}


function ea_display_setting($args)
{
    extract( $args );

    $option_name = 'ea_theme_options';

    $options = get_option( $option_name );

    switch ( $type ) {  
          case 'text':  
              $options[$id] = stripslashes($options[$id]);  
              $options[$id] = esc_attr( $options[$id]);  
              echo "<input class='regular-text$class' type='text' id='$id' name='" . $option_name . "[$id]' value='$options[$id]' />";  
              echo ($desc != '') ? "<br /><span class='description'>$desc</span>" : "";  
          break;  
    }
}

/**
 * Callback function to the register_settings function will pass through an input variable
 */
function ea_validate_settings($input)
{
  foreach($input as $k => $v)
  {
    $newinput[$k] = trim($v);

    // Check the input is a letter or a number
    if(!preg_match('/^[A-Z0-9 _]*$/i', $v)) {
      $newinput[$k] = '';
    }
  }

  return $newinput;
}