如何在wordpress中修复对未定义函数get_woocommerce_currency（）的调用？

Question

I'm developing a custom shipping plugin to my WooCommerce website.

I want to change shipping method to my custom method if and only if the user's currency is USD. Apart from USD, I'm using LKR as my other currency unit. If the currency is in LKR different shipping method should be applied.

So I tried to check whether the user's current base currency is in USD by using this code in my plugin.php file,

My plugin.php code includes in -> wp-content/plugins/my-plugin

 if ( 'USD' !== get_woocommerce_currency() ) {
    echo 'Hello  ';
    //my action
}   

So now every time I run this code I'm getting a fatal error saying

Call to undefined function get_woocommerce_currency()

Then I tried including the option.php ,

include_once('wp-includes/option.php');

still getting the same error message.

How to fix it and why I'm getting that error?

What I want to do is just to check user's current currency and activate the plugin if the currency is only in USD.

Thanks.

Answer 1

The fix for your issue will depend on how/when you're calling those lines of code you have.

One is if you've added a hook on woocommerce_init this won't be a problem.

A very very simple example to show what I mean.

add_action( 'woocommerce_init', 'wc_init' );
function wc_init(){
    // get_woocommerce_currency() will not throw error here.
}

If you're making a plugin that should work alongside with WooCommerce, I suggest you run your plugin init inside a function hook to woocommerce_init.

---

I'm not really sure what you're up to. But if you're just interested in the currency, might as well just do this:

$currency = apply_filters( 'woocommerce_currency', get_option( 'woocommerce_currency' ) );
if ( 'USD' !== $currency ) {
    echo 'Hello  ';
    //my action
}

Again, working alongside with WooCommerce, you should use 'woocommerce_init' to hook your function.

---

update 3

function add_chalitha_shipping_method( $methods ) {
    if ( 'USD' == get_woocommerce_currency() ) {
         $methods[] = 'test_Shipping_Method';
    }
    return $methods;
}