Snippet to hide normal shipping methods if any Freight Shipping Class in cart else Hide Freight Shipping methods if any normal WooCommerce Shipping Class product in cart. PluginHive Plugins - https://www.pluginhive.com/product/multiple-carrier-shipping-plugin-woocommerce/, https://www.pluginhive.com/product/woocommerce-ups-shipping-plugin-with-p…

functions.php

/**
 * Snippet to hide normal shipping methods based if any freight shipping class in cart else hide freight shipping method if any normal shipping class product in cart.
 * Created at : 27 July 2018
 * Updated at : 27 July 2018
 * PluginHive Plugins : https://www.pluginhive.com/plugins/
 * Gist Link : https://gist.github.com/xadapter/0504f1442d9c21d7014543bfc7589f78
 */

add_filter( 'woocommerce_package_rates', 'ph_hide_shipping_method_based_on_shipping_class', 10, 2 );

if( ! function_exists('ph_hide_shipping_method_based_on_shipping_class') ) {
	function ph_hide_shipping_method_based_on_shipping_class( $shipping_rates, $package ) {
		
		$hide_shipping_rates_based_on_shipping_class = array(
				'normal_shipping_class'		=> array(
					'shipping_class'			=>	array('smart_phone'),			// Normal Shipping classes
					'shipping_method_to_hide'	=>	array('flat_rate:1'),			// Freight shipping method
				),
				'freight_shipping_class'	=> array(
					'shipping_class'			=>	array('shoe'),					// Freight shipping classes
					'shipping_method_to_hide'	=>	array('free_shipping:2'),			// Normal shipping method
				),
		);

		$hide_freight_rates = $hide_normal_rates = false;
		foreach( $package['contents'] as $line_item ) {
			$line_item_shipping_class = $line_item['data']->get_shipping_class();
			if( ! empty($line_item_shipping_class) ) {
				if( in_array( $line_item_shipping_class, $hide_shipping_rates_based_on_shipping_class['freight_shipping_class']['shipping_class'] ) ) {
					$hide_normal_rates = true;
					break;
				}
				elseif( in_array( $line_item_shipping_class, $hide_shipping_rates_based_on_shipping_class['normal_shipping_class']['shipping_class'] ) ) {
					$hide_freight_rates = true;
				}
			}
		}

		$shipping_methods_to_hide = array();
		if( $hide_normal_rates ) {
			$shipping_methods_to_hide = $hide_shipping_rates_based_on_shipping_class['freight_shipping_class']['shipping_method_to_hide'];
		}
		elseif( $hide_freight_rates ) {
			$shipping_methods_to_hide = $hide_shipping_rates_based_on_shipping_class['normal_shipping_class']['shipping_method_to_hide'];
		}

		foreach( $shipping_rates as $key => $shipping_rate ) {
			$id = $shipping_rate->get_id();
			if( in_array( $id, $shipping_methods_to_hide) ) {
				unset( $shipping_rates[$key] );
			}
		}
		return $shipping_rates;
	}
}