iosswiftxcodelocalizationpluralize

Xcode, Swift: how to add multi-language support in an iOS app and have strings with placeholders and plurals?

I need to add multi-language support in an iOS app that is written in Xcode using Swift. I need to localize

  1. Static strings
  2. Strings with placeholders
  3. plurals (quantity-strings)

Such as below in Android we add named strings and plurals in XML files:

<string name="static_string">Hello world!</string>
<string name="placeholder_string">You have %2$d new messages.</string>
<plurals name="plural_string">
    <item quantity="one">You have a new message.</item>
    <item quantity="other">You have %2$d new messages.</item>
</plurals>

And following Java to get strings programmatically:

res.getString(R.string.placeholder_string, mailCount)
res.getQuantityString(R.plurals.plural_string, mailCount, mailCount)

I am looking for the solution corresponding to Swift (iOS)

Solution

  • Setup project Localizations, as shown in screenshot the project has English and Russian languages.

    enter image description here

    1: Create a file named Localizable.strings and add following lines

    static_string="Hello world!";
placeholder_string="You have %d new messages.";

    2: We define Plurals in a separate file, lets create a file named Localizable.stringsdict and paste following:

    <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">

<!-- FIRST PLURAL STRING -->
<dict>
    <key>plural_string</key>
    <dict>
        <key>NSStringLocalizedFormatKey</key>
        <string>%#@value@</string>
        <key>value</key>
        <dict>
            <key>NSStringFormatSpecTypeKey</key>
            <string>NSStringPluralRuleType</string>
            <key>NSStringFormatValueTypeKey</key>
            <string>d</string>
            <key>one</key>
            <string>You have a new message.</string>
            <key>other</key>
            <string>You have %d new messages.</string>
        </dict>
    </dict>
</dict>

<!-- NEXT PLURAL STRING -->
</plist>

    Next, localize Localizable.stringsdict file, see in screenshot, the file is localized for English and Russian languages:

    enter image description here

    Usage:

    NSLocalizedString("static_string", comment: "") // Hello world!

String(format: NSLocalizedString("placeholder_string", comment: ""), 5) // You have 5 new messages.

let plural = NSLocalizedString("plural_string", comment: "")
String(format: plural, 1) // You have a new message.
String(format: plural, 2) // You have 2 new messages.

    Plural Rules: In XML code, notice <key>one</key> and <key>other</key>, here you can use zero, one, two, few, many, other depending on the language and your requirements.

    Use following link for more information on language specific plural rules: http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html

    Also this article will help if you are new to string formatting https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/Strings/Articles/formatSpecifiers.html