rnkyr / reactive-localization

Introduce reactive localisation to your project with RxSwift and SwiftGen

Reactive localization with RxSwift and SwiftGen

Overview

The project demonstrates an approach to localize your project with the ability to select interface language in run-time without the need to drastically change your codebase.

Main requirements for a task were to reduce the number of changes needed to be introduced to support real-time language changing and to work with SwiftGen.

To achieve this, I decided to create a custom stencil for a SwiftGen and cover all the reactiveness there.

How to use

• Add rx_strings.stencil to your project directory.

• Tune your swiftgen to use that stencil.

At the time of writing, swiftgen does not support running codegen for strings twice, so instead of running simply swiftgen, you need to run it twice - default one and another one with parameters:

${PODS_ROOT}/SwiftGen/bin/swiftgen
${PODS_ROOT}/SwiftGen/bin/swiftgen strings Example/Supporting\ Files/en.lproj/Localizable.strings --templatePath rx_strings.stencil --output Example/Extensions/Swiftgen/RxStrings.swift

• Now you can use generated code

was:

label.title = L10n.someTitle

become:

label.localizedTitle = RxL10n.someTitle

• To change language, run Bundle.setLanguage(with:) passing exact language code.

The Example project demonstrates all the described steps.

Implementation details

The rx_strings.stencil is based on flat-swift4.stencil and extends it to create additional helper methods for UIKit's classes, methods to change and manipulate localization schema. It also changes tr method to return Observable<String>. Nothing more changed, so you can copy-paste the code to any other stencil.

To use proper Bundle (e.g. "localized" one), stencil overrides NSLocalizedString method publicly. Each time language changed through Bundle.setLanguage it changes currentLanguage static variable, which triggers any subscribers that use tr method.

To improve API, stencil adds extensions for major UIKit classes with properties like var localizedText: Observable<String> that can be used to directly bind localized text.