Disable Add to Cart button in a product category?

Hey ciptanegara!

Thank you for using our theme.

Probably the init hook is to early for the has_term function.

Try the following:

add_action('init','remove_add_to_cart_button', 1000);

function remove_add_to_cart_button() {
                remove_action( 'woocommerce_after_shop_loop_item', 'avia_add_cart_button', 16);
		remove_action( 'woocommerce_single_product_summary', 'woocommerce_template_single_add_to_cart', 30 );
}

add_action( 'woocommerce_after_shop_loop_item', 'my_add_to_cart_button', 16 );
add_action( 'woocommerce_single_product_summary', 'my_add_to_cart_button_single', 30 );

function my_add_to_cart_button() {
     if ( ! has_term( 'free-gift', 'product_cat' ) ) {
                  avia_add_cart_button();
       }
}

function my_add_to_cart_button_single() {
     if ( ! has_term( 'free-gift', 'product_cat' ) ) {
                  woocommerce_template_single_add_to_cart();
       }
}

Best regards,
Günter