Localizing Mobile Apps

Localizing Mobile Apps
Daniel Schneller, CenterDevice GmbH

Agenda
I18N vs. L10N
Languages and Regions
Text
Date and Time
Numbers
Images and other Resources
https://github.com/dschneller/I18N-Example

I — 18 Characters — N
L-10 Characters-N

Internationalization
I — 18 Characters — N
Localization
L-10 Characters-N

Internationalization
[…] process of designing a software application so that it
can potentially be adapted to various languages and
regions without engineering changes. […]*
* Wikipedia

Localization
[…] the process of adapting internationalized software for
a speciﬁc region or language by adding locale-speciﬁc
components and translating text. […]*
* Wikipedia

I18N L10NApp
Localized 
App
!"#$%&!
! 🌐 🌐 !"#
$%&

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

Scheme Launch Arguments
-AppleLanguages (ar,de,fr)
Order determines preference
-AppleLocale en_US

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

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

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

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
…

Base Localization
One leading (base)
language

Base Localization
One leading (base)
language
Add Localization

Base Localization
One leading (base)
language
Add Localization
“.strings”files

Base Localization
One leading (base)
language
Add Localization
“.strings”files
genstrings

Base Localization
One leading (base)
language
Add Localization
“.strings”files
genstrings
ibtool

Base Localization
One leading (base)
language
Add Localization
“.strings”files
genstrings
ibtool
One copy per language

Base Localization
One leading (base)
language
Add Localization
“.strings”files
genstrings
ibtool
One copy per language
“.lproj”Ordner

Base Localization
Eine Leitsprache (Base)
“.strings”Files
genstrings
ibtool
Eine Kopie pro Sprache
“.lproj”Ordner

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";
…

Base Localization
Preview in Assistant Editor
Xcode 6: Pick Language
Double-Length Pseudo-
Language
Auto Layout

NSLocalizedString
Family of macros
NSLocalizedString 
NSLocalizedStringFromTable 
NSLocalizedStringFromTableInBundle 
NSLocalizedStringWithDefaultValue
Access “.strings”files
Utilize NSBundle
-[[NSBundle mainBundle] localizedStringForKey:value:table:]

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";

.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

Do not normalize text
DRY! — Do Repeat Yourself
[NSString stringWithFormat:@”…”]

Localizable.strings
“count” = “Anzahl”
“game” = “Spiel”
“reset” = “zurücksetzen”
“save” = “sparen”
“thumbnail” = “Daumennagel”

Localizable.strings
“count” = “Anzahl”
“game” = “Spiel”
“reset” = “zurücksetzen”
“save” = “sparen”
“thumbnail” = “Daumennagel”
“reset count”
”zurücksetzen Anzahl”
“save game”
“sparen Spiel”
…

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

Use self explanatory keys
Provide useful comments (button vs. label, approx. length, etc.)

Variables
Parameters
[NSString stringWithFormat: 
NSLocalizedString(@"click.counter.label", 
@"P1: Current Click Count."), 
self.clickCount]
"
/* P1: Current Click Count. */ 
"click.counter.label" = "%1d x geklickt”;

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”;

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.

Englisch Deutsch
1 1 book 1 Buch
Vielleicht nicht ganz…
Plural

Englisch Deutsch
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

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

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
‫كتاب‬ ٠
‫كتاب‬
‫كتابان‬
‫كتب‬ ٣
‫ا‬ً‫ب‬‫كتا‬ ١١
‫كتاب‬ ١٠٠
Or is it…?
Plural

.strings + .stringsdict
* http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html#ar

Available since iOS7

Implements (Unicode*) localization rules for
Plural
Gender [rdar://16670931]

Implements (Unicode*) localization rules for
Plural
Gender [rdar://16670931]
Plist Format
Name must match .strings
.strings must exist, but may be empty

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>

.stringsdict
Categories per language according to Unicode
iOS additionally supports„zero“ category for all languages
Others, e. g.„few“, depend on language

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

Date and Time
Transforms between NSDate and NSString
+[NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:] 
-[NSDateFormatter setLocale:]
NSDateFormatter

Date and Time
NSDateFormatterStyle
NSDateFormatter

Date and Time
German / Germany Englisch / USA
NSDateFormatter

Date and Time
Short 08.07.14 22:32 7/8/14,10:32 PM
NSDateFormatter

Date and Time
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

Date and Time
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

Date and Time
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
Full Dienstag, 8. Juli 2014 12:32:36
Mitteleuropäische Sommerzeit
Tuesday, July 8, 2014 at 12:39:16 PM
Central European Summer Time
NSDateFormatter

Date and Time
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
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

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

Date and Time NSDateFormatter
* http://www.unicode.org/reports/tr35/tr35-dates.html#Contents

Date and Time
What if defaults are not suitable?
NSDateFormatter

Date and Time
Do not use hard coded format strings!
NSDateFormatter

Date and Time
Unicode Locale Data Markup Language*
NSDateFormatter

Date and Time
[f setDateFormat:[NSDateFormatter 
dateFormatFromTemplate:@"u QQ"  
options:0 
locale:LOCALE_EN_US]]; 
 
NSLog(@“%@", [f stringFromDate:july8th);
NSDateFormatter

Date and Time
[f setDateFormat:[NSDateFormatter 
dateFormatFromTemplate:@"u QQ"  
options:0 
locale:LOCALE_EN_US]]; 
 
NSLog(@“%@", [f stringFromDate:july8th);
Q3 2014
NSDateFormatter

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…

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

Numbers
MassDistance
LengthCurrency
Percentage
Data Volume
WeightEnergy
Spelled Out
“Plain”Numbers

Numbers
Decimal separators
Grouping characters
Currency symbols
…
"
NSNumberFormatter
API similar to NSDateFormatter

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

Numbers
NSNumberFormatter.h
enum { 
NSNumberFormatterNoStyle = …, 
NSNumberFormatterDecimalStyle = …, 
NSNumberFormatterCurrencyStyle = …, 
NSNumberFormatterPercentStyle = …, 
NSNumberFormatterScientificStyle = …, 
NSNumberFormatterSpellOutStyle = … 
} 
typedef NSUInteger NSNumberFormatterStyle

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

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

Numbers
Many more customization options
maximumFractionDigits
usesSignificantDigits
minimum/maximumSignificantDigits
paddingCharacter
roundingMode, roundingIncrement
…
NSNumberFormatter

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

Coming up next: iOS8
NSEnergyFormatter
Energy in joule, calories etc.
NSLengthFormatter
Distance, in miles, kilometers etc.
NSMassFormatter
Mass and weight in pounds, kg etc.

UI Elements
-[UIImage imageNamed:@"myImage"];
Put image files into .lproj folders
Does not work for asset catalogues

Launch Image
Disable asset catalogue
Launch images in .lproj folders
Follows usual naming conventions for
Retina
Orientation
iPhone vs. iPad

Other Ressources
Same as images
Lookup via
-[[NSBundle mainBundle] pathForResource:ofType:]
Use cases
HTML
Text files

App Name
Info.plist
Application has localized Display Name
<key>LSHasLocalizedDisplayName</key> 
<true />
InfoPlist.strings
"CFBundleDisplayName" = "国际范例";

Cover the Basics
Locale based formatting
NSDateFormatter
NSNumberFormatter
NSByteCountFormatter
Careful and diligent translation
Remember resources besides the source code

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
…

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

Merci!
Hvala!
Vielen Dank! Thank You!
Grazie!

Questions?
Daniel Schneller — @dschneller  
daniel.schneller@centerdevice.com

Localizing Mobile Apps

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