Что такое начальная загрузка?

Вы можете использовать свою собственную логику, которая рекурсивно решает вложенные строки.

/**
 * Regex that matches a resource string such as <code>@string/a-b_c1</code>.
 */
private static final String REGEX_RESOURCE_STRING = "@string/([A-Za-z0-9-_]*)";

/** Name of the resource type "string" as in <code>@string/...</code> */
private static final String DEF_TYPE_STRING = "string";

/**
 * Recursively replaces resources such as <code>@string/abc</code> with
 * their localized values from the app's resource strings (e.g.
 * <code>strings.xml</code>) within a <code>source</code> string.
 * 
 * Also works recursively, that is, when a resource contains another
 * resource that contains another resource, etc.
 * 
 * @param source
 * @return <code>source</code> with replaced resources (if they exist)
 */
public static String replaceResourceStrings(Context context, String source) {
    // Recursively resolve strings
    Pattern p = Pattern.compile(REGEX_RESOURCE_STRING);
    Matcher m = p.matcher(source);
    StringBuffer sb = new StringBuffer();
    while (m.find()) {
        String stringFromResources = getStringByName(context, m.group(1));
        if (stringFromResources == null) {
            Log.w(Constants.LOG,
                    "No String resource found for ID \"" + m.group(1)
                            + "\" while inserting resources");
            /*
             * No need to try to load from defaults, android is trying that
             * for us. If we're here, the resource does not exist. Just
             * return its ID.
             */
            stringFromResources = m.group(1);
        }
        m.appendReplacement(sb, // Recurse
                replaceResourceStrings(context, stringFromResources));
    }
    m.appendTail(sb);
    return sb.toString();
}

/**
 * Returns the string value of a string resource (e.g. defined in
 * <code>values.xml</code>).
 * 
 * @param name
 * @return the value of the string resource or <code>null</code> if no
 *         resource found for id
 */
public static String getStringByName(Context context, String name) {
    int resourceId = getResourceId(context, DEF_TYPE_STRING, name);
    if (resourceId != 0) {
        return context.getString(resourceId);
    } else {
        return null;
    }
}

/**
 * Finds the numeric id of a string resource (e.g. defined in
 * <code>values.xml</code>).
 * 
 * @param defType
 *            Optional default resource type to find, if "type/" is not
 *            included in the name. Can be null to require an explicit type.
 * 
 * @param name
 *            the name of the desired resource
 * @return the associated resource identifier. Returns 0 if no such resource
 *         was found. (0 is not a valid resource ID.)
 */
private static int getResourceId(Context context, String defType,
        String name) {
    return context.getResources().getIdentifier(name, defType,
            context.getPackageName());
}

Например, из Activity вызывает его так

replaceResourceStrings(this, getString(R.string.message_text));