android源码学习 yii2源码学习笔记十七）

Theme 类，应用的主题，通过替换路径实现主题的应用，方法为获取根路径和根链接：yii2\base\Theme.php

  1 php
  2/**
  3 * @link http://www.yiiframework.com/  4 * @copyright Copyright (c) 2008 Yii Software LLC
  5 * @license http://www.yiiframework.com/license/  6*/  7  8namespace yii\base;
  9 10use Yii;
 11use yii\helpers\FileHelper;
 12 13/**
 14 * Theme represents an application theme.
 15 * Theme 类，应用的主题
 16 * When [[View]] renders a view file, it will check the [[View::theme|active theme]]
 17 * to see if there is a themed version of the view file exists. If so, the themed version will be rendered instead.
 18 * 视图对象[[View]]渲染视图文件的时候，会检查视图的主题是否存在，如果存在则渲染主题取代默认样式
 19 * A theme is a directory consisting of view files which are meant to replace their non-themed counterparts.
 20 *
 21 * Theme uses [[pathMap]] to achieve the view file replacement:
 22 *
 23 * 1. It first looks for a key in [[pathMap]] that is a substring of the given view file path;
 24 *  首先查找关键字，关键字是一个给定的视图路径的字符串
 25 * 2. If such a key exists, the corresponding value will be used to replace the corresponding part
 26 *    in the view file path;关键字存在，则用对应值替换给定的视图文件路径中对应的部分
 27 * 3. It will then check if the updated view file exists or not. If so, that file will be used
 28 *    to replace the original view file.检查替换后的路径对应的文件是否存在，存在就替换原文件
 29 * 4. If Step 2 or 3 fails, the original view file will be used.
 30 * 2和3失败的话，返回原来的路径
 31 * For example, if [[pathMap]] is `['@app/views' => '@app/themes/basic']`,
 32 * then the themed version for a view file `@app/views/site/index.php` will be
 33 * `@app/themes/basic/site/index.php`.
 34 *
 35 * It is possible to map a single path to multiple paths. For example,
 36 *
 37 * ~~~
 38 * 'pathMap' => [
 39 *     '@app/views' => [
 40 *         '@app/themes/christmas',
 41 *         '@app/themes/basic',
 42 *     ],
 43 * ]
 44 * ~~~
 45 *
 46 * In this case, the themed version could be either `@app/themes/christmas/site/index.php` or
 47 * `@app/themes/basic/site/index.php`. The former has precedence over the latter if both files exist.
 48 *
 49 * To use a theme, you should configure the [[View::theme|theme]] property of the "view" application
 50 * component like the following:
 51 *
 52 * ~~~
 53 * 'view' => [
 54 *     'theme' => [
 55 *         'basePath' => '@app/themes/basic',
 56 *         'baseUrl' => '@web/themes/basic',
 57 *     ],
 58 * ],
 59 * ~~~
 60 *
 61 * The above configuration specifies a theme located under the "themes/basic" directory of the Web folder
 62 * that contains the entry script of the application. If your theme is designed to handle modules,
 63 * you may configure the [[pathMap]] property like described above.
 64 *
 65 * @property string $basePath The root path of this theme. All resources of this theme are located under this
 66 * directory.
 67 * @property string $baseUrl The base URL (without ending slash) for this theme. All resources of this theme
 68 * are considered to be under this base URL. This property is read-only.
 69 *
 70 * @author Qiang Xue  71 * @since 2.0
 72*/ 73class Theme extends Component
 74{
 75/**
 76     * @var array the mapping between view directories and their corresponding themed versions.
 77     * This property is used by [[applyTo()]] when a view is trying to apply the theme.
 78     * Path aliases can be used when specifying directories.
 79     * 路径映射属性 设置替换映射关系
 80     * If this property is empty or not set, a mapping [[Application::basePath]] to [[basePath]] will be used.
 81*/ 82public $pathMap;
 83 84private $_baseUrl;//设置要访问资源的url 85 86/**
 87     * @return string the base URL (without ending slash) for this theme. All resources of this theme are considered
 88     * to be under this base URL. 返回当前主题的基础链接，其他资源都在链接里
 89*/ 90public function getBaseUrl()
 91    {
 92return $this->_baseUrl;
 93    }
 94 95/**
 96     * @param $url string the base URL or path alias for this theme. All resources of this theme are considered
 97     * to be under this base URL. 设置基础链接
 98*/ 99public function setBaseUrl($url)
100    {
101         $this->_baseUrl = rtrim(Yii::getAlias($url), '/');
102    }
103104private $_basePath;//根路径105106/**
107     * @return string the root path of this theme. All resources of this theme are located under this directory.
108     * 得到当前主题的根路径
109     * @see pathMap
110*/111public function getBasePath()
112    {
113return $this->_basePath;
114    }
115116/**
117     * @param string $path the root path or path alias of this theme. All resources of this theme are located
118     * under this directory. 设置当前主题根路径
119     * @see pathMap
120*/121public function setBasePath($path)
122    {
123         $this->_basePath = Yii::getAlias($path);
124    }
125126/**
127     * Converts a file to a themed file if possible. 将一个文件替换主题文件
128     * If there is no corresponding themed file, the original file will be returned.
129     * 没有相应的主题文件，返回原文件。
130     * @param string $path the file to be themed
131     * @return string the themed file, or the original file if the themed version is not available.
132     * @throws InvalidConfigException if [[basePath]] is not set
133*/134public function applyTo($path)
135    {
136         $pathMap = $this->pathMap; //取得路径映射137if (empty($pathMap)) {//没有设置值 抛出异常138if (($basePath = $this->getBasePath()) === null) {
139thrownew InvalidConfigException('The "basePath" property must be set.');
140            }
141//设置值为[模块根路径=>主题根路径]的形式142             $pathMap = [Yii::$app->getBasePath() => [$basePath]];
143        }
144145         $path = FileHelper::normalizePath($path);//对路径中的"/"."\"进行统一146147foreach ($pathMap as $from => $tos) {
148//映射数组中的来源149             $from = FileHelper::normalizePath(Yii::getAlias($from)) . DIRECTORY_SEPARATOR;
150if (strpos($path, $from) === 0) {//如果在$path中有可替换的旧值151                 $n = strlen($from);
152foreach ((array) $tos as $to) {
153                     $to = FileHelper::normalizePath(Yii::getAlias($to)) . DIRECTORY_SEPARATOR;
154                     $file = $to . substr($path, $n);//把$path中的$from替换为$to155if (is_file($file)) {
156return $file; //是文件直接返回157                    }
158                }
159            }
160        }
161162return $path;
163    }
164165/**
166     * Converts a relative URL into an absolute URL using [[baseUrl]].
167     * 将一个相对URL转换为绝对URL
168     * @param string $url the relative URL to be converted.要转换的相对URL
169     * @return string the absolute URL  替换后的绝对URL
170     * @throws InvalidConfigException if [[baseUrl]] is not set
171*/172public function getUrl($url)
173    {
174if (($baseUrl = $this->getBaseUrl()) !== null) {//URL存在，进行转换175return $baseUrl . '/' . ltrim($url, '/');
176         } else {//不存在抛出异常177thrownew InvalidConfigException('The "baseUrl" property must be set.');
178        }
179    }
180181/**
182     * Converts a relative file path into an absolute one using [[basePath]].
183     * 通过相对路径生成绝对路径
184     * @param string $path the relative file path to be converted. 要转换的相对文件路径。
185     * @return string the absolute file path 转换后的绝对路径
186     * @throws InvalidConfigException if [[baseUrl]] is not set
187*/188public function getPath($path)
189    {
190if (($basePath = $this->getBasePath()) !== null) {
191//返回拼接的路径192return $basePath . DIRECTORY_SEPARATOR . ltrim($path, '/\\');
193         } else {
194thrownew InvalidConfigException('The "basePath" property must be set.');
195        }
196    }
197 }

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