Translate plugin admin interface

Question

I'm using Poedit to create the .po and .mo files to translate the admin interface of a custom plugin.

All works fine, but I don't know where I've to store these new .po and .mo files to use these translations, how to rename the files and so on.

Please, could you help me?

Thanks

Answer 1

Excerpts from Plugin Handbook

The text domain must match the slug of the plugin. If your plugin is a single file called my-plugin.php or it is contained in a folder called my-plugin the domain name should be my-plugin. If your plugin is hosted on wordpress.org it must be the slug of your plugin URL (wordpress.org/plugins/). The text domain name must use dashes and not underscores. The text domain also needs to be added to the plugin header. WordPress uses it to internationalize your plugin meta-data even when the plugin is disabled. The text domain should be same as the one used when loading the text domain.

/*
 * Plugin Name: My Plugin
 * Author: Plugin Author
 * Text Domain: my-plugin
 */

The domain path is used so that WordPress knows where to find the translation when the plugin is disabled. Only useful if the translations are located in a separate language folder. For example, if .mo files are located in the languages folder within your plugin then Domain Path will be “/languages” and must be written with the first slash. Defaults to the languages folder of the plugin:

/*
 * Plugin Name: My Plugin
 * Author: Plugin Author
 * Text Domain: my-plugin
 * Domain Path: /languages
 */

Answer

Let's assume that your plugin name is My Plugin and your translation is for Polish language. There will be three files: my-plugin.pot, my-plugin-pl_PL.po, and my-plugin-pl_PL.mo.

It is a good practice to put in your plugin's languages folder, one .pot file, and pairs of .po / .mo for each language.

Put the following files, my-plugin.pot, my-plugin-pl_PL.po, my-plugin-pl_PL.mo into '/wp-content/plugins/my-plugin/languages' folder.

The following code will be used to properly load your plugin text domain:

function my_init() {
    load_plugin_textdomain( 'my-plugin', false, 'my-plugin/languages/' );
}
add_action( 'init', 'my_init' );

or, if you call it from a class:

function my_init() {
    load_plugin_textdomain( 'my-plugin', false, 'my-plugin/languages/' );
}
add_action( 'init', array( $this, 'my_init' ) );