Advanced WordPress Development

Chapter 5: Theme Development

5.1 Theme Structure

WordPress themes follow a specific structure.

Required Files:

• style.css: Theme stylesheet with header
• index.php: Main template file
• functions.php: Theme functions

5.2 Template Hierarchy

WordPress selects templates based on hierarchy.

// Template hierarchy example
single.php
single-{post_type}.php
single-{post_type}-{slug}.php
singular.php
index.php

5.3 Child Themes

Use child themes to customize parent themes safely.

/*
Theme Name: Child Theme
Template: parent-theme
*/

// Enqueue parent theme styles
function child_theme_enqueue_styles() {
    wp_enqueue_style('parent-style', get_template_directory_uri() . '/style.css');
}
add_action('wp_enqueue_scripts', 'child_theme_enqueue_styles');

5.4 Theme Customization API

Use the Customizer API for theme options.

// Add customizer section
add_action('customize_register', 'my_theme_customize_register');

function my_theme_customize_register($wp_customize) {
    $wp_customize->add_section('my_section', array(
        'title' => 'My Section',
        'priority' => 30,
    ));
    
    $wp_customize->add_setting('my_setting', array(
        'default' => 'default_value',
    ));
    
    $wp_customize->add_control('my_setting', array(
        'label' => 'My Setting',
        'section' => 'my_section',
        'type' => 'text',
    ));
}

5.5 Theme Development Best Practices

Follow best practices for theme development.

• Use semantic HTML5
• Follow WordPress coding standards
• Make themes responsive
• Optimize for performance
• Ensure accessibility
• Test across browsers