Preparing Views for Localization

Overview 概要

Localize your SwiftUI views so users experience your app in their own native language, region, and culture.

Xcode parses Text views for strings to localize when exporting a localization catalog. You can add hints and use string interpolation specifiers for these views so that Xcode generates correct, hinted strings to localize for your app. For non-text views, add the strings and related comments into a Localizable.strings file.

Add Comments to Text Views

To ease the translation process, provide hints to translators that share how and where your app displays the strings of a Text view. To add a hint, use the optional comment parameter to the text view initializer init(_:tableName:bundle:comment:). When you localize your app with Xcode, it includes the comment string along with the string. For example, by setting a comment on the text provided to a navigation title:

 navigationTitle(Text("Landmarks", comment: "navigation title"))

Xcode creates the following strings file entry:

/* navigation title */
"Landmarks" = "Landmarks";

Provide a Specifier When Using String Interpolation

Text views can use string interpolation to replace variables with values while assembling strings. If you use interpolated strings for your Text views, provide a format parameter for localization. When Xcode parses Text views that use interpolated strings, it defaults to using a specifier of %@, which may not be correct for the type of value. For a list of available specifiers, see String Format Specifiers.

Specify the correct alternative using the specifier parameter in the interpolation. The following example uses %lld to interpolate a 64 bit integer into a string within a text view:

Text("Copying \(copyOperation.numFiles, specifier: "%lld") files",
    comment: "File copy message that indicates the number of files copied by the operation")

Xcode creates the following strings file entry:

/* File copy message that indicates the number of files copied by the operation */
"Copying %lld files" = "Copying %lld files";

Add Localization Strings for Non-Text Views

For anything other than a text view, initialize the view with text views or add strings for your app to provide localized views. You can localize other views, such as Label or Picker, as they accept a LocalizedStringKey on initialization. Because Xcode doesn’t parse these views for localization, you need to manually add the localization strings.

To localize non-text views, create a Localizable.strings file in your project. Add localized text to the file for any SwiftUI views that take LocalizedStringKey on initialization. Make sure to include a comment to share the context of where and how your app uses the string for your translators. For example, to localize a Label view initialized with a string:

Label("Message", image: "msgSymbol")

Add the string values and a comment to the Localizable.strings file:

/* A label that displays 'Message' and a corresponding image. */
"Message" = "Message";

Alternately, initialize the label with a text view:

Label {
    Text("Message",
         comment: "A label that displays 'Message' and a corresponding image.")
} icon: {
    Image("msgSymbol")
}

For more information about editing strings files, see Editing XLIFF and Strings Files.