harmony 鸿蒙Multi-Language Capability

2022-12-13
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Multi-Language Capability

Applications designed based on the development framework apply to different countries and regions. With the multi-language capability, you do not need to develop application versions in different languages, and your users can switch between various locales. This also facilitates project maintenance.

You only need to perform operations in Defining Resource Files and Referencing Resources to use the multi-language capability of this framework.

Defining Resource Files

Resource files store application content in multiple languages. This framework uses JSON files to store resource definitions.

Place the resource file of each locale in the i18n directory described in File Organization. Resource files are named in *language-region*.json format. For example, the resource file for English (United States) is named en-US.json. If there is no resource file of the locale that matches the system language, content in the en-US.json file will be used by default.

Different languages have different matching rules for singular and plural forms. In the resource file, zero, one, two, few, many, and other are used to define the string content in different singular and plural forms. For example, there is only the other scenario in Chinese since the language does not have singular and plural forms. One and other scenarios are applicable to English. All the preceding six scenarios are needed for Arabic.

The following example takes en-US.json and ar-AE.json as examples:

{
    "strings": {
        "hello": "Hello world!",
        "symbol": "@#$%^&*()_+-={}[]\\|:;\"'<>,./?",
        "plurals": {
            "one": "one person",
            "other": "other people"
        }
    },

    "files": {
        "image": "image/en_picture.PNG"
    }
}

{
    "strings": {
        "plurals": {
            "zero": "لا أحد",
            "one": "وحده",
            "two": "اثنان",
            "few": "ستة اشخاص",
            "many": "خمسون شخص",
            "other": "مائة شخص"
        }
    }
}

Referencing Resources

Multi-language syntax used on application development pages (including simple formatting and singular-plural formatting) can be used in .hml or .js files.

Simple formatting Use the $t function to reference to resources of different locales. The $t function is available for both .hml and .js files. The system displays content based on a resource file path specified via $t and the specified resource file whose locale matches the current system language.

Table 1 Simple formatting

Name	Type	Parameter	Mandatory	Description
$t	Function	Described in $t parameters	Yes	Sets the parameters based on the system language, for example, this.$t(‘strings.hello’).

**Table 2** $t parameters

Name	Type	Mandatory	Description
path	string	Yes	Resource path.

Example code for simple formatting

  <!-- xxx.hml -->
   <div> 
     <text>{{ $t('strings.hello') }}</text>  
     <image src="{{ $t('files.image') }}" class="image"></image> 
   </div>

Singular-Plural Conversion

Table 3 Singular-plural conversion

Name	Type	Parameter	Mandatory	Description
$tc	Function	Described in $tc parameters	Yes	Converts between the singular and plural forms based on the system language, for example, this.$tc(‘strings.plurals’). The resource content is distinguished by the following JSON keys: zero, one, two, few, many, and other.

Table 4 $tc parameters

Parameter	Type	Mandatory	Description
path	string	Yes	Resource path.
count	number	Yes	Number

Example code for converting between the singular and plural forms

  <!--xxx.hml-->
  <div>
      <!-- When the value 0 is passed, "0 people" matches the Arabic string whose key is zero. -->
    <text>{{ $tc('strings.plurals', 0) }}</text>
      <!-- When the value 1 is passed, "1 person" matches the Arabic string whose key is one. -->
    <text>{{ $tc('strings.plurals', 1) }}</text>
      <!-- When the value 2 is passed, "2 people" matches the Arabic string whose key is two. -->
    <text>{{ $tc('strings.plurals', 2) }}</text>
      <!-- When the value 6 is passed, "6 people" matches the Arabic string whose key is few. -->
    <text>{{ $tc('strings.plurals', 6) }}</text>
      <!-- When the value 50 is passed, "50 people" matches the Arabic string whose key is many. -->
    <text>{{ $tc('strings.plurals', 50) }}</text>
      <!-- When the value 100 is passed, "100 people" matches the Arabic string whose key is other. -->
    <text>{{ $tc('strings.plurals', 100) }}</text>
  </div>