Android开发第3-1课：支持不同的语言

This class teaches you to

Create Locale Directories and String Files
Use the String Resources

You should also read

Localization

It’s always a good practice to extract UI strings from your app code and keep themin an external file. Android makes this easy with a resources directory in each Androidproject.

If you created your project using the Android SDKTools (read
Creating anAndroid Project), the tools create a

res/

directory in the top level ofthe project. Within this

res/

directory are subdirectories for various resourcetypes. There are also a few default files such as

res/values/strings.xml

,
which holdsyour string values.

Create Locale Directories and String Files

To add support for more languages, create additional

values

directories inside

res/

that include a hyphen and the ISO country code at the end of thedirectory name. For example,

values-es/

is the directory containing simpleresourcess
for the Locales with the language code "es". Android loads the appropriate resourcesaccording to the locale settings of the device at run time.

Once you’ve decided on the languages you will support, create the resource subdirectories andstring resource files. For example:

MyProject/
    res/
       values/
           strings.xml
       values-es/
           strings.xml
       values-fr/
           strings.xml

Add the string values for each locale into the appropriate file.

At runtime, the Android system uses the appropriate set of string resources based on thelocale currently set for the user's device.

For example, the following are some different string resource files for different languages.

English (default locale),

/values/strings.xml

:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="title">My Application</string>
    <string name="hello_world">Hello World!</string>
</resources>

Spanish,

/values-es/strings.xml

:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="title">Mi Aplicación</string>
    <string name="hello_world">Hola Mundo!</string>
</resources>

French,

/values-fr/strings.xml

:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="title">Mon Application</string>
    <string name="hello_world">Bonjour le monde !</string>
</resources>

Note: You can use the locale qualifier (or anyconfiguration qualifer) on any resource type, such as if you want to providelocalized versions of your bitmap drawable. For more information, seeLocalization.

Use the String Resources

You can reference your string resources in your source code and other XML files using theresource name defined by the

<string>

element's

name

attribute.

In your source code, you can refer to a string resource with the syntax

R.string.<string_name>

. There are a variety of methods that accept a string resource thisway.

For example:

// Get a string resource from your app's [code]Resources

String hello =

getResources()

.getString(R.string.hello_world);

// Or supply a string resource to a method that requires a string
TextView textView = new TextView(this);
textView.setText(R.string.hello_world);[/code]
In other XML files, you can refer to a string resource with the syntax

@string/<string_name>

whenever the XML attribute accepts a string value.

For example:

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />