A converter from Android's strings.xml to gettext PO format for use with online translation services like PO Editor and Launchpad. Store it in a directory within your Android project. It will output a strings_<locale>.po file. You can store 'context' information (to help translators) in a YAML file with the string names as keys and context descr…

android_xml_to_po.rb

#!/usr/bin/ruby

require 'nokogiri'
require 'fileutils'
require 'yaml'
require 'optparse'

@PROJECT_ID_VERSION = 'ttrscoreboard-android'
@REPORT_MSGID_BUGS_TO = '' # Where to report (A URL or email address)

@EXCLUDE_FIELDS = [ "about_translators" ]

@CONTEXTS_FILE = 'contexts.yml'

########################################################################
# Reference language information
# (the strings stored in values/strings.xml
########################################################################


# Additional help: http://www.gnu.org/software/gettext/manual/gettext.html#index-header-entry-of-a-PO-file-265

# Language code
# Can be any of the following:
#   "ll" An ISO 639 two-letter language code in lowercase
#   "ll_CC" the above with the addition of an ISO 3166 two-letter country code in uppercase
#   "ll_CC@variant" the above with the addition of the variant designator (eg. latin/cyrillic)
@LANGUAGE = 'en-GB'

# Content type (for the reference language)
@CONTENT_TYPE = 'UTF-8'

########################################################################

@options = {}
OptionParser.new do |opts|
	opts.banner = "Usage: ruby android_xml_to_po.rb [options]"
	
	opts.on("-t", "--translation LANGUAGE",
		"Create a PO file for the given translation") do |value|
		@options[:translation] = value
		@translation_path = File.join('..', 'res', "values-#{value}", 'strings.xml')
		abort "Cannot find strings file for values-#{value}" unless File.exists?(@translation_path)
		@LANGUAGE = value
	end
end.parse!


# translator-comments
#. extracted-comments
#: reference
#, flag
#| msgid previous-untranslated-string
#msgid "untranslated string"
#msgstr "translated string"

def header_entry
	header_entry = Array.new

	header_entry.push "Project-Id-Version: #{@PROJECT_ID_VERSION}"
	header_entry.push "Language: #{@LANGUAGE}"
	header_entry.push "Report-Msgid-Bugs-To: #{@REPORT_MSGID_BUGS_TO}"
	header_entry.push "POT-Creation-Date: #{Time.now.strftime('%F %H:%M%z')}"
	header_entry.push "MIME-Version: 1.0"
	header_entry.push "Content-Type: text/plain; charset=#{@CONTENT_TYPE}"
	header_entry.push "Content-Transfer-Encoding: 8bit"
	header_entry.push "X-Generator: android_xml_to_po.rb"
	
	%|msgid ""\n| +
	%|msgstr #{header_entry.map!{|x| %|"#{x}\\n"|}.insert(0,%|""|).join("\n")}|
end

def entry(field_name, reference_string, translated_string, context=nil)

	entry = Array.new

	#white-space
	entry.push ""
	entry.push ""
	# translator-comments
	#"# #{context}" unless context.nil?
	#. extracted-comments
	#: reference
  entry.push "#: #{field_name}" unless field_name.nil?
	#, flag
	#| msgid previous-untranslated-string
	#msgid "untranslated string"
	#msgctxt "Context for the translation"
	entry.push %|msgctxt "#{clean_string(context)}"| unless context.nil?
	entry.push %|msgid "#{clean_string(reference_string)}"|
	entry.push %|msgstr "#{clean_string(translated_string)}"|
	#msgstr "translated string"
	
	return entry.join("\n")
end

def clean_string(string)
#
	return string.gsub(/\n/, '\n').gsub(/\\n\s*/, '\n').gsub(%q|\'|, "'")
end

def get_strings(strings_path)

	if File.exists?(strings_path)
		doc = Nokogiri.XML File.read(strings_path)
		
		strings = Hash.new

		doc.xpath('/resources/string').each do |string|
			strings[string.attributes['name'].to_s] = string.content.to_s unless @EXCLUDE_FIELDS.include?(string.attributes['name'].to_s)
		end
		return strings
	end
	abort "File not found: #{strings_path}"
end

def get_contexts
	if File.exists? @CONTEXTS_FILE
		YAML.load_file(@CONTEXTS_FILE)
	else
		Array.new
	end
end

def output_po
	f = header_entry
	
	reference_strings_path = File.join('..', 'res', 'values', 'strings.xml')
	
	strings = get_strings reference_strings_path
	translated_strings = get_strings @translation_path if @options[:translation]
	contexts = get_contexts
	
	strings.each do |field,str|
	
		if @options[:translation]
			if translated_strings[field]
				translated_string = translated_strings[field]
			else
				translated_string = str
			end
		else
			translated_string = str
		end
	
		if contexts[field].nil?
			f << entry(field,str,translated_string)
		else
			f << entry(field,str,translated_string,contexts[field])
		end
	end
	return f
end

def write_po
	File.open("strings_#{@LANGUAGE}.po", 'w') { |file| file.write(output_po) }
end

def print_po
	puts output_po
end

write_po

Changes

• Now has a command-line argument -t to set the translation language code to use for the msgstr strings (ie. create a PO file which has translated strings rather than just reference strings).
• The script now outputs valid PO files (previously they were invalid if single quotes existed in a string)
• The script now supports multi-line strings