Localizing Mobile Apps

English Slides for my talk originally given at Developer Week 2014 in Nuremberg, Germany. It covers internationalization and localization of mobile applications, using iOS as an example platform. I look at text, numbers, date and time, images and other resources, using correct plural forms and more.

There is an example application available on GitHub: https://github.com/dschneller/I18N-Example

Transcript

1. Localizing Mobile Apps Daniel Schneller, CenterDevice GmbH
2. Agenda I18N vs. L10N Languages and Regions Text Date and Time Numbers Images and other Resources https://github.com/dschneller/I18N-Example
3. I18N vs. L10N
4. I18N L10N
5. I — 18 Characters — N L-10 Characters-N
6. Internationalization I — 18 Characters — N Localization L-10 Characters-N
7. Internationalization
8. Internationalization […] process of designing a software application so that it can potentially be adapted to various languages and regions without engineering changes. […]* * Wikipedia
9. Localization
10. Localization […] the process of adapting internationalized software for a specific region or language by adding locale-specific components and translating text. […]* * Wikipedia
12. I18N L10N App Localized
 App !"#$%& ! ! !"# $%&
13. Languages and Regions
14. Languages and Regions Language ≠ Region 12h time used by an American living in Germany „Jänner“ – „Januar“ [German in Austria vs. in Germany for January] Localization ≠ Locale German user might prefer English user interface texts But: 24h time display
15. Languages and Regions
16. Languages and Regions
17. Languages and Regions
18. Languages and Regions Scheme Launch Arguments -AppleLanguages (ar,de,fr) Order determines preference -AppleLocale en_US
19. NSLocale Encapsulates Region Settings + (id)autoupdatingCurrentLocale
 + (id)currentLocale NSCurrentLocaleDidChangeNotification [[NSNotificationCenter defaultCenter]
 addObserver:self
 selector:@selector(localeDidChange:)
 name:NSCurrentLocaleDidChangeNotification
 object:nil] Refresh formatters, caches NSLocale instances Refresh screen content
20. NSLocale -[NSLocale objectForKey:] NSString* NSLocaleIdentifier NSString* NSLocaleMeasurementSystem NSString* NSLocaleLanguageCode NSString* NSLocaleDecimalSeparator NSString* NSLocaleCountryCode NSString* NSLocaleGroupingSeparator NSString* NSLocaleScriptCode NSString* NSLocaleCurrencySymbol NSString* NSLocaleVariantCode NSString* NSLocaleExemplarCharacterSet NSString* NSLocaleCurrencyCode NSString* NSLocaleCollatorIdentifier NSString* NSLocaleCalendar NSString* NSLocaleQuotationBeginDelimiterKey NSString* NSLocaleCollationIdentifier NSString* NSLocaleQuotationEndDelimiterKey NSString* NSLocaleUsesMetricSystem
21. NSLocale Does not contain the current language! Locale ≠ Localization [NSBundle mainBundle].localizations; // NSArray, (all) [NSBundle mainBundle].preferredLocalizations[0]; // (current) Caveats Localizations of InfoPlist.strings determine content of „localizations“ Intersected with user’s region preferences in Settings.app AppleLanguages launch parameter
22. Text
25. Text ≠ Text Language of messages, buttons, labels etc. Writing direction & alignment Writing systems (Latin, Hebrew, Arabic…) Numbers in text Names & addresses Phrases, idioms and terminology Plurals Sorting …
26. Text ≠ Text Language of messages, buttons, labels etc. Writing direction & alignment Writing systems (Latin, Hebrew, Arabic…) Numbers in text Names & addresses Phrases, idioms and terminology Plurals Sorting …
27. Base Localization
28. Base Localization One leading (base) language
29. Base Localization One leading (base) language Add Localization
30. Base Localization One leading (base) language Add Localization
31. Base Localization One leading (base) language Add Localization “.strings” files
32. Base Localization One leading (base) language Add Localization “.strings” files genstrings
33. Base Localization One leading (base) language Add Localization “.strings” files genstrings ibtool
34. Base Localization One leading (base) language Add Localization “.strings” files genstrings ibtool One copy per language
35. Base Localization One leading (base) language Add Localization “.strings” files genstrings ibtool One copy per language “.lproj” Ordner
36. Base Localization Eine Leitsprache (Base) “.strings” Files genstrings ibtool Eine Kopie pro Sprache “.lproj” Ordner
37. Base Localization Eine Leitsprache (Base) “.strings” Files genstrings ibtool Eine Kopie pro Sprache “.lproj” Ordner
38. Base Localization Eine Leitsprache (Base) “.strings” Files genstrings ibtool Eine Kopie pro Sprache “.lproj” Ordner
39. Base Localization … /* Class = "IBUILabel"; text = "Loaded by SecondViewController"; ObjectID = "NDk-cv-Gan"; */ "NDk-cv-Gan.text" = "Loaded by SecondViewController"; " /* Class = "IBUILabel"; text = "First View"; ObjectID = "KQZ-1w-vlD"; */ "KQZ-1w-vlD.text" = "First View"; …
40. Base Localization Preview in Assistant Editor Xcode 6: Pick Language Double-Length Pseudo- Language Auto Layout
41. NSLocalizedString Family of macros NSLocalizedString
 NSLocalizedStringFromTable
 NSLocalizedStringFromTableInBundle
 NSLocalizedStringWithDefaultValue Access “.strings” files Utilize NSBundle -[[NSBundle mainBundle] localizedStringForKey:value:table:]
42. NSLocalizedString Example [button setTitle:NSLocalizedString(@"reset.counter.button.title", 
 @"Reset Counter action button")
 forState:…]; genstrings — Localizable.strings /* Reset Counter action button */
 "reset.counter.button.title" = "Zurücksetzen";
43. .strings Files Updates?
44. .strings Files Updates? Use ibtool every time you update your labels and text.
 In the Base.lproj folder:
 
 ibtool ChangedNib.xib --generate-strings- file NewStrings.strings
 
 Open the generated output file and copy all new string entries to ChangedNib.strings in each lproj. #fail
45. Do not normalize text
46. Do not normalize text DRY! — Do Repeat Yourself [NSString stringWithFormat:@”…”]
47. Do not normalize text DRY! — Do Repeat Yourself [NSString stringWithFormat:@”…”] Localizable.strings “count” = “Anzahl” “game” = “Spiel” “reset” = “zurücksetzen” “save” = “sparen” “thumbnail” = “Daumennagel”
48. Do not normalize text DRY! — Do Repeat Yourself [NSString stringWithFormat:@”…”] Localizable.strings “count” = “Anzahl” “game” = “Spiel” “reset” = “zurücksetzen” “save” = “sparen” “thumbnail” = “Daumennagel” “reset count” ”zurücksetzen Anzahl” “save game” “sparen Spiel” …
49. Do not normalize text
50. Do not normalize text Context and grammar are lost
51. Do not normalize text Context and grammar are lost Structure of sentences
52. Do not normalize text Context and grammar are lost Structure of sentences Declination & conjugation …
53. Do not normalize text Context and grammar are lost Structure of sentences Declination & conjugation … Use dedicated strings per use case
54. Do not normalize text Context and grammar are lost Structure of sentences Declination & conjugation … Use dedicated strings per use case “reset.counter.button” = “Auf 0 stellen”
55. Do not normalize text Context and grammar are lost Structure of sentences Declination & conjugation … Use dedicated strings per use case “reset.counter.button” = “Auf 0 stellen” Context for translators
56. Do not normalize text Context and grammar are lost Structure of sentences Declination & conjugation … Use dedicated strings per use case “reset.counter.button” = “Auf 0 stellen” Context for translators Use self explanatory keys
57. Do not normalize text Context and grammar are lost Structure of sentences Declination & conjugation … Use dedicated strings per use case “reset.counter.button” = “Auf 0 stellen” Context for translators Use self explanatory keys Provide useful comments (button vs. label, approx. length, etc.)
58. Variables Parameters [NSString stringWithFormat:
 NSLocalizedString(@"click.counter.label",
 @"P1: Current Click Count."),
 self.clickCount] " /* P1: Current Click Count. */
 "click.counter.label" = "%1d x geklickt”;
59. Variables Document parameter order! “Zeige 4 von 12 gesamt” “Total 12 — Showing 4” /* … Param 1: current page; Param 2: total count */
 "current.page.label" = “Zeige %1d von %2d gesamt”;
 
 /* … Param 1: current page; Param 2: total count */
 "current.page.label" = “Total %2d — Showing %1d”;
60. Special cases: 0 and 1 Plurals Englisch German 0 No books Keine Bücher 1 One book Ein Buch sonstiges 100 books 100 Bücher Localizable.strings “books.0” = “No Books” “books.1” = “One Book” “books.n” = “%1d books” “books.0” = “Keine Bücher” “books.1” = “Ein Buch” “books.n” = “%1d Bücher” If-else-clause in the code: Problem solved.
61. Englisch Deutsch 0 No books Keine Bücher 1 1 book 1 Buch Vielleicht nicht ganz… Plural
62. Englisch Deutsch 0 No books Keine Bücher 1 1 book 1 Buch 2 2 books 2 Bücher wenige 3 books 3 Bücher viele 11 books 11 Bücher sonstiges 100 books 100 Bücher Vielleicht nicht ganz… Plural
63. 0 1 2 wenige viele sonstiges Englisch No books 1 book 2 books 3 books 11 books 100 books German Keine Bücher 1 Buch 2 Bücher 3 Bücher 11 Bücher 100 Bücher Or is it…? Plural
64. 0 1 2 wenige viele sonstiges Englisch No books 1 book 2 books 3 books 11 books 100 books German Keine Bücher 1 Buch 2 Bücher 3 Bücher 11 Bücher 100 Bücher Arabic باتك ٠ باتك ناباتك بتك ٣ اًباتك ١١ باتك ١٠٠ Or is it…? Plural
65. .strings + .stringsdict * http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html#ar
66. .strings + .stringsdict Available since iOS7 * http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html#ar
67. .strings + .stringsdict Available since iOS7 Implements (Unicode*) localization rules for Plural Gender [rdar://16670931] * http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html#ar
68. .strings + .stringsdict Available since iOS7 Implements (Unicode*) localization rules for Plural Gender [rdar://16670931] Plist Format Name must match .strings .strings must exist, but may be empty * http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html#ar
69. .strings + .stringsdict https://developer.apple.com/library/ios/releasenotes/Foundation/↩︎ RN-Foundation/index.html#//apple_ref/doc/uid/TP30000742-CH2-SW56 <dict>
 <key>files.selected.label.%d</key>
 <dict>
 <key>NSStringLocalizedFormatKey</key>
 <string>%#@num_files_are@ selected</string>
 <key>num_files_are</key>
 <dict>
 <key>NSStringFormatSpecTypeKey</key>
 <string>NSStringPluralRuleType</string>
 <key>NSStringFormatValueTypeKey</key>
 <string>d</string>
 <key>zero</key> <string>No file is</string>
 <key>one</key> <string>A file is</string>
 <key>other</key> <string>%d files are</string>
 </dict>
 </dict>
 </dict>
70. .stringsdict Categories per language according to Unicode iOS additionally supports „zero“ category for all languages Others, e. g. „few“, depend on language
71. String Tables Localizable.strings Default used by NSLocalizedString() Big projects — big file Can be split NSLocalizedStringFromTable(“MyController”, “Key”, “Comment”) MyController.strings Project structure — Context for translators 3rd party code Also works for .stringsdict
72. Date and Time
73. Date and Time NSDateFormatter
74. Date and Time Transforms between NSDate and NSString +[NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:]
 -[NSDateFormatter setLocale:] NSDateFormatter
75. Date and Time Transforms between NSDate and NSString +[NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:]
 -[NSDateFormatter setLocale:] NSDateFormatterStyle NSDateFormatter
76. Date and Time Transforms between NSDate and NSString +[NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:]
 -[NSDateFormatter setLocale:] NSDateFormatterStyle German / Germany Englisch / USA NSDateFormatter
77. Date and Time Transforms between NSDate and NSString +[NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:]
 -[NSDateFormatter setLocale:] NSDateFormatterStyle German / Germany Englisch / USA Short 08.07.14 22:32 7/8/14,10:32 PM NSDateFormatter
78. Date and Time Transforms between NSDate and NSString +[NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:]
 -[NSDateFormatter setLocale:] NSDateFormatterStyle German / Germany Englisch / USA Short 08.07.14 22:32 7/8/14,10:32 PM Medium 08.07.2014 22:32:36 Jul 8, 2014, 10:32:36 PM NSDateFormatter
79. Date and Time Transforms between NSDate and NSString +[NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:]
 -[NSDateFormatter setLocale:] NSDateFormatterStyle German / Germany Englisch / USA Short 08.07.14 22:32 7/8/14,10:32 PM Medium 08.07.2014 22:32:36 Jul 8, 2014, 10:32:36 PM Long 8. Juli 2014 22:32:36 MESZ Jul 8, 2014, 10:32:36 PM GMT+2 NSDateFormatter
80. Date and Time Transforms between NSDate and NSString +[NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:]
 -[NSDateFormatter setLocale:] NSDateFormatterStyle German / Germany Englisch / USA Short 08.07.14 22:32 7/8/14,10:32 PM Medium 08.07.2014 22:32:36 Jul 8, 2014, 10:32:36 PM Long 8. Juli 2014 22:32:36 MESZ Jul 8, 2014, 10:32:36 PM GMT+2 Full Dienstag, 8. Juli 2014 12:32:36 Mitteleuropäische Sommerzeit Tuesday, July 8, 2014 at 12:39:16 PM Central European Summer Time NSDateFormatter
81. Date and Time Transforms between NSDate and NSString +[NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:]
 -[NSDateFormatter setLocale:] NSDateFormatterStyle German / Germany Englisch / USA Short 08.07.14 22:32 7/8/14,10:32 PM Medium 08.07.2014 22:32:36 Jul 8, 2014, 10:32:36 PM Long 8. Juli 2014 22:32:36 MESZ Jul 8, 2014, 10:32:36 PM GMT+2 Full Dienstag, 8. Juli 2014 12:32:36 Mitteleuropäische Sommerzeit Tuesday, July 8, 2014 at 12:39:16 PM Central European Summer Time No - - NSDateFormatter
82. Date and Time NSDateFormatter.h typedef enum {
 NSDateFormatterNoStyle = …,
 NSDateFormatterShortStyle = …,
 NSDateFormatterMediumStyle = …,
 NSDateFormatterLongStyle = …,
 NSDateFormatterFullStyle = …
 } NSDateFormatterStyle Combine for date and time portions NSDateFormatterNoStyle — only date / time Get updated with the OS NSDateFormatter
83. Date and Time NSDateFormatter * http://www.unicode.org/reports/tr35/tr35-dates.html#Contents
84. Date and Time What if defaults are not suitable? NSDateFormatter * http://www.unicode.org/reports/tr35/tr35-dates.html#Contents
85. Date and Time What if defaults are not suitable? Do not use hard coded format strings! NSDateFormatter * http://www.unicode.org/reports/tr35/tr35-dates.html#Contents
86. Date and Time What if defaults are not suitable? Do not use hard coded format strings! Unicode Locale Data Markup Language* NSDateFormatter * http://www.unicode.org/reports/tr35/tr35-dates.html#Contents
87. Date and Time What if defaults are not suitable? Do not use hard coded format strings! Unicode Locale Data Markup Language* [f setDateFormat:[NSDateFormatter
 dateFormatFromTemplate:@"u QQ" 
 options:0
 locale:LOCALE_EN_US]];
 
 NSLog(@“%@", [f stringFromDate:july8th); NSDateFormatter * http://www.unicode.org/reports/tr35/tr35-dates.html#Contents
88. Date and Time What if defaults are not suitable? Do not use hard coded format strings! Unicode Locale Data Markup Language* [f setDateFormat:[NSDateFormatter
 dateFormatFromTemplate:@"u QQ" 
 options:0
 locale:LOCALE_EN_US]];
 
 NSLog(@“%@", [f stringFromDate:july8th); Q3 2014 NSDateFormatter * http://www.unicode.org/reports/tr35/tr35-dates.html#Contents
89. Relative formatting [formatter setDoesRelativeDateFormatting:YES];
 
 NSLog(@“%@, %@, %@…", [formatter stringFromDate:GESTERN],
 [formatter stringFromDate:HEUTE],
 [formatter stringFromDate:MORGEN]);
 Gestern, Heute, Morgen… [de_DE] Yesterday, Today, Tomorrow… [en_US] Yesterday, Today, Tomorrow…
90. NSDateComponentsFormatter Formats durations [f stringFromTimeInterval:1234.0]) // seconds About 20 minutes remaining NSDateIntervalFormatter Formats time intervals [f stringFromDate:NOW toDate:LATER]) 09.07.14 12:10-13:13 Coming up next: iOS8
91. Numbers
92. Numbers
93. Numbers “Plain” Numbers
94. Numbers Mass Distance Length Currency Percentage Data Volume Weight Energy Spelled Out “Plain” Numbers
95. Numbers Decimal separators Grouping characters Currency symbols … " NSNumberFormatter API similar to NSDateFormatter
96. Numbers NSNumberFormatter German / Germany English / USA No 1234,56 1234.56 Decimal 1.234,56 1,234.56 Currency 1.234,56 € $1,234.56 Percent 123.456% 123,456% Scientific 1,23456E+03 1.23456E3 SpellOut eintausendzweihundertvier- unddreißig Komma fünf sechs one thousand two hundred thirty- four point five six
97. Numbers NSNumberFormatter.h enum {
 NSNumberFormatterNoStyle = …,
 NSNumberFormatterDecimalStyle = …,
 NSNumberFormatterCurrencyStyle = …,
 NSNumberFormatterPercentStyle = …,
 NSNumberFormatterScientificStyle = …,
 NSNumberFormatterSpellOutStyle = …
 }
 typedef NSUInteger NSNumberFormatterStyle
98. Numbers NSNumberFormatter
99. Numbers NSNumberFormatter* f = [[NSNumberFormatter alloc] init];
 f.numberStyle = NSNumberFormatterNoStyle; f.locale = LOCALE_DE_AT;
 NSLog(@"NoStyle de_AT: %@", [f stringFromNumber:@(1234.56)]); f.locale = LOCALE_EN_US;
 f.maximumFractionDigits = 2;
 NSLog(@“NoStyle en_US: %@", [f stringFromNumber:@(1234.56)]); NSNumberFormatter
100. Numbers NSNumberFormatter* f = [[NSNumberFormatter alloc] init];
 f.numberStyle = NSNumberFormatterNoStyle; f.locale = LOCALE_DE_AT;
 NSLog(@"NoStyle de_AT: %@", [f stringFromNumber:@(1234.56)]); f.locale = LOCALE_EN_US;
 f.maximumFractionDigits = 2;
 NSLog(@“NoStyle en_US: %@", [f stringFromNumber:@(1234.56)]); NoStyle de_AT: 1235 NoStyle en_US: 1234.56 NSNumberFormatter
101. Numbers Many more customization options maximumFractionDigits usesSignificantDigits minimum/maximumSignificantDigits paddingCharacter roundingMode, roundingIncrement … NSNumberFormatter
102. Data Volume NSByteCountFormatter File size, amount of memory Picks suitable unit automatically Non-numeric display Allow Non-Numeric Zero KB File 1,234.57 GB Memory 1,149.78 GB
103. Coming up next: iOS8 NSEnergyFormatter Energy in joule, calories etc. NSLengthFormatter Distance, in miles, kilometers etc. NSMassFormatter Mass and weight in pounds, kg etc.
104. Images and other Resources
105. Images Buttons UI Elements
106. UI Elements -[UIImage imageNamed:@"myImage"]; Put image files into .lproj folders Does not work for asset catalogues
107. Launch Image Disable asset catalogue Launch images in .lproj folders Follows usual naming conventions for Retina Orientation iPhone vs. iPad
108. Other Ressources Same as images Lookup via -[[NSBundle mainBundle] pathForResource:ofType:] Use cases HTML Text files
109. App Name Info.plist Application has localized Display Name <key>LSHasLocalizedDisplayName</key>
 <true /> InfoPlist.strings "CFBundleDisplayName" = "国际范例";
110. Wrap up
111. Cover the Basics Locale based formatting NSDateFormatter NSNumberFormatter NSByteCountFormatter Careful and diligent translation Remember resources besides the source code
112. Next Steps Images resources Launch Images (if relevant) Addresses, names Right-to-left support Location based pre-selection of units (miles, km etc.) Pre-selection for pickers, options etc. Color scheme …
113. Summary Initialer effort can be significant Full translation Code refactoring Create workflows and pick tools Ongoing maintenance rather easy Consider relevance of individual measures for your audience
114. Merci! Hvala! Vielen Dank! Thank You! Grazie!
115. Questions? Daniel Schneller — @dschneller 
 daniel.schneller@centerdevice.com