Demonstrates the use of custom taxonomy fields with Admin Page Framework, a WordPress libaray.

admin-page-framework-tutorial-14-taxonomy-fields.php

<?php
/**
 *  Plugin Name:    Admin Page Framework Tutorial 14 - Taxonomy Fields
 *  Plugin URI:     http://en.michaeluno.jp/admin-page-framework
 *  Description:    Demonstrates the use of custom taxonomy fields with Admin Page Framework.
 *  Author:         Michael Uno
 *  Author URI:     http://michaeluno.jp
 *  Version:        1.0.0
 */

// Include the library file. Set your correct file path here.
include( dirname( dirname( __FILE__ ) ) . '/admin-page-framework/library/apf/admin-page-framework.php' );
 
class APF_Tutorial_TaxonomyField extends AdminPageFramework_TaxonomyField {
        
    /*
     * Defines custom taxonomy fields.
     */
    public function setUp() {

        $this->addSettingFields(
            array(
                'field_id'      => 'my_image',
                'type'          => 'image',
                'title'         => __( 'Image', 'admin-page-framework-tutorial' ),
                'attributes'    => array(
                    'preview' => array(
                        'style' => 'max-width: 200px;',
                    ),
                ),
            )
        );     
        
    }

    /**
     * Modifies the columns of the term listing table.
     * @callback        filter      column_{instantiated class name}
     */
    public function columns_APF_Tutorial_TaxonomyField( $aColumns ) { 
        
        unset( $aColumns[ 'description' ] );
        return array( 
                'cb'        => $aColumns[ 'cb' ],
                'thumbnail' => __( 'Thumbnail', 'admin-page-framework-tutorial' ),
            ) 
            + $aColumns;
        
    }
    
    /**
     * Modifies the cell of the `thumbnail` column.
     * @callback    filter      cell_{instantiated class name}_{cell slug}
     * @return      string
     */
    public function cell_APF_Tutorial_TaxonomyField_thumbnail( $sCellHTML, $iTermID ) { 
    
        $_aOptions = get_option( 
            'APF_Tutorial_TaxonomyField', // option key - by default the class name is the option key.
            array() // - default value in case a value is not set.
        ); 
        $_sImageURL = $this->oUtil->getElement( 
            $_aOptions,
            array( $iTermID, 'my_image' ),
            ''  // default value
         );
        return $_sImageURL
            ? "<img src='{$_sImageURL}' style='max-height: 72px; max-width: 120px;'/>"
            : $sCellHTML;
        
    }
    
    /**
     * Inserts custom text.
     * 
     * @callback        action      do_{instantiated class name}
     */
    public function do_APF_Tutorial_TaxonomyField() { 
        ?>
            <p><?php _e( 'This text is inserted with the <code>do_{instantiated class name}</code> hook.', 'admin-page-framework-tutorial' ) ?></p>
        <?php     
    }
 
    
    /**
     * Validates submitted option values.
     * @return      array
     * @callback    filter      validation_{class name}
     */
    public function validation_APF_Tutorial_TaxonomyField( $aInputs, $aOldInputs ) {
        return $aInputs;
    }
    
}

new APF_Tutorial_TaxonomyField( 
    'category'   // taxonomy slug     
);