Yii2 framework学习笔记(三) -- 语言与国际化

t() public static method
Translates a message to the specified language.
This is a shortcut method of yii\i18n\I18N::translate().
The translation will be conducted according to the message category and the target language will be used.
You can add parameters to a translation message that will be substituted with the corresponding value after translation. 
The format for this is to use curly brackets around the parameter name as you can see in the
following example:

[code]$username = 'Alexander';
echo \Yii::t('app', 'Hello, {username}!', ['username' => $username]);

Further formatting of message parameters is supported using the PHPintl extensions message formatter. See yii\i18n\I18N::translate() formore details.
public static stringt ($category, $message, $params = [],$language = null )    
$category    string    The message category.    
$message    string    The message to be translated.    
$params    array    The parameters that will be used to replace the corresponding placeholders in the message.    
$language    string    The language code (e.g.en-US,en).If this is null, the current application language will be used.    
return
string    The translated message.

'components' => [
        ...
    	'i18n' => [
    		'translations' => [
    			'common' => [
    				'class' => 'yii\i18n\PhpMessageSource',
    				'basePath' => '@common/messages',
    				'fileMap' => [
    					'common' => 'common.php',
    				],
    			],
    		],	
    	],
        ...
    ],

<?php  
return [  
    &#39;Signup&#39; => &#39;注册&#39;,  
    &#39;Login&#39; => &#39;登陆&#39;,  
    &#39;Logout&#39; => &#39;登出&#39;,  
    &#39;Home&#39; => &#39;首页&#39;,  
    &#39;Contact&#39; => &#39;反馈&#39;,  
    &#39;About&#39; => &#39;关于&#39;,  
];

$menuItems = [  
        //['label' => 'Home', 'url' => ['/site/index']],  
        //['label' => 'About', 'url' => ['/site/about']],  
        //['label' => 'Contact', 'url' => ['/site/contact']],  
        ['label' => \Yii::t('common', 'Home'), 'url' => ['/site/index']],  
        ['label' => \Yii::t('common', 'About'), 'url' => ['/site/about']],  
        ['label' => \Yii::t('common', 'Contact'), 'url' => ['/site/contact']],  
    ];

<?php  
return [  
   &#39;language&#39; => &#39;zh-CN&#39;,  
   ...  
];

<?php  
return [  
    &#39;language&#39; => &#39;zh-CN&#39;,  
  
    &#39;components&#39; => [  
        ...  
    ],  
    &#39;params&#39; => [  
        &#39;availableLanguages&#39; => [  
            &#39;zh-CN&#39; => [&#39;img&#39; => &#39;image/zh.png&#39;, &#39;desc&#39; => &#39;中文&#39;],  
            &#39;en-US&#39; => [&#39;img&#39; => &#39;image/en.png&#39;, &#39;desc&#39; => &#39;English&#39;],  
        ],  
    ],  
    ...  
];

<?php

namespace common\widgets;

use Yii;
use yii\helpers\Html;
use yii\helpers\Url;

class LanguageSelector
{
	public static function getMenu()
	{
		$lang = Yii::$app->language;
		$avLang = Yii::$app->params[&#39;availableLanguages&#39;];
		$isMatch = false;
		foreach ($avLang as $key => $value) {
			if($key == $lang) {
				$tag = LanguageSelector::buildImgTag($value[&#39;img&#39;], $value[&#39;desc&#39;]);
				$isMatch = true;
			}
		}
		if(!$isMatch) {
			$tag = LanguageSelector::buildImgTag($avLang[0][&#39;img&#39;], $avLang[0][&#39;desc&#39;]);
		}
		$return = [
			&#39;label&#39; => $tag, 
			&#39;items&#39; => LanguageSelector::buildMenuItems($avLang),
		];
		
		return $return;
	}	
	
	private static function buildImgTag($src, $desc)
	{
		return &#39;<img src="&#39; . $src . &#39;" alt="&#39; . $desc . &#39;">&#39;;
	}
	
	private static function buildMenuItems($langs)
	{
		foreach ($langs as $key => $value) {
			$link = Html::a(LanguageSelector::buildImgTag($value[&#39;img&#39;], $value[&#39;desc&#39;]) . &#39; &#39; . $value[&#39;desc&#39;], Url::home(), [
					&#39;title&#39; => LanguageSelector::buildImgTag($value[&#39;img&#39;], $value[&#39;desc&#39;]) . &#39; &#39; . $value[&#39;desc&#39;],
					&#39;onclick&#39;=>"
					     $.ajax({
					    type     :&#39;POST&#39;,
					    cache    : false,
					    url  : &#39;" . Url::toRoute("ajax/lang") . "&#39;,
						data: { _lang : &#39;" . $key . "&#39; },
					    success  : function(response) {
					        window.location.reload();
					    }
					    });return false;",
			]);
			$menuItems[] = &#39;<li>&#39; . $link . &#39;</li>&#39;;
		}
		return $menuItems;
	}
}

<?php

namespace frontend\controllers;

use Yii;
use yii\web\Controller;
use common\components\SelectLanguageBehavior;
use yii\web\cookie;

class AjaxController extends Controller {
	public $layout = false;
	
	public function actionLang() {
		if (isset($_POST[&#39;_lang&#39;]))
		{
			$lang = SelectLanguageBehavior::getSelectedLanguage($_POST[&#39;_lang&#39;]);
			Yii::$app->language = $lang;
			$cookie = new cookie([
					&#39;name&#39; => &#39;_lang&#39;,
					&#39;value&#39; => $lang,
			] );
			$cookie->expire = time() + (60*60*24*365); // (1 year)
			Yii::$app->response->cookies->add($cookie);
		}
		return "success";
	}
	
}

<?php
namespace common\components;

use yii\base\Application;
use yii\base\Behavior;
use yii\web\cookie;
use Yii;
class SelectLanguageBehavior extends Behavior
{
	public function events()
	{
		return [
				Application::EVENT_BEFORE_REQUEST => &#39;beforeRequest&#39;,
		];
	}
	
	public function beforeRequest($event) {
		$app = Yii::$app;
	
		$lang = SelectLanguageBehavior::getSelectedLanguage(Yii::$app->request->cookies->getValue(&#39;_lang&#39;));
		$app->language = $lang;
	}
	
	public static function getSelectedLanguage($val) {
		$langs = Yii::$app->params[&#39;availableLanguages&#39;];
		foreach ($langs as $key=>$value) {
			if($val == $key) {
				return $val;
			}
		}
		return key($langs);
	}
}

<?php  
return [  
    &#39;language&#39; => &#39;zh-CN&#39;,  
  
    &#39;components&#39; => [  
        ...  
    ],  
    ...  
    &#39;as beginRequest&#39; => [  
            &#39;class&#39; => &#39;common\components\SelectLanguageBehavior&#39;,  
    ],  
];

...
    if (Yii::$app->user->isGuest) {
        $menuItems[] = ['label' => Yii::t('common', 'Signup'), 'url' => ['/site/signup']];
        $menuItems[] = ['label' => Yii::t('common', 'Login'), 'url' => ['/site/login']];
    } else {
        $menuItems[] = [
            'label' => Yii::t('common', 'Logout') . ' (' . Yii::$app->user->identity->username . ')',
            'url' => ['/site/logout'],
            'linkOptions' => ['data-method' => 'post']
        ];
    }
	
	// add this line
        $menuItems[] = \common\widgets\LanguageSelector::getMenu();
	
	echo Nav::widget([
        'options' => [
        	'class' => 'navbar-nav navbar-right',
        	],
        'items' => $menuItems,
        // add this line
    	'encodeLabels' => false,
    ]);
	...