android源码学习 yii2源码学习笔记十九）

view剩余代码

  1/**
  2     * @return string|boolean the view file currently being rendered. False if no view file is being rendered.
  3     * 当前正在渲染的视图文件
  4*/  5public function getViewFile()
  6    {
  7return end($this->_viewFiles);
  8    }
  9 10/**
 11     * This method is invoked right before [[renderFile()]] renders a view file.
 12     * The default implementation will trigger the [[EVENT_BEFORE_RENDER]] event.
 13     * 前置事件，执行[renderFile()]时被调用，默认触发[[EVENT_BEFORE_RENDER]]事件
 14     * If you override this method, make sure you call the parent implementation first.
 15     * @param string $viewFile the view file to be rendered. 要渲染的视图文件。
 16     * @param array $params the parameter array passed to the [[render()]] method.
 17     * 参数数组传递到[render()]方法。
 18     * @return boolean whether to continue rendering the view file. 是否继续渲染视图文件。
 19*/ 20public function beforeRender($viewFile, $params)
 21    {
 22         $event = new ViewEvent([//实例化ViewEvent 23'viewFile' => $viewFile,
 24'params' => $params,
 25        ]);
 26         $this->trigger(self::EVENT_BEFORE_RENDER, $event);//触发[EVENT_BEFORE_RENDER]事件 27 28return $event->isValid;//判断是否继续渲染文件 29    }
 30 31/**
 32     * This method is invoked right after [[renderFile()]] renders a view file.
 33     * The default implementation will trigger the [[EVENT_AFTER_RENDER]] event.
 34     * 后置事件，在执行[renderFile()]方法后被调用，默认触发[[EVENT_AFTER_RENDER]]事件
 35     * If you override this method, make sure you call the parent implementation first.
 36     * @param string $viewFile the view file being rendered.要渲染的视图文件。
 37     * @param array $params the parameter array passed to the [[render()]] method.
 38     * 参数数组传递到[render()]方法。
 39     * @param string $output the rendering result of the view file. Updates to this parameter
 40     * will be passed back and returned by [[renderFile()]].
 41     * 返回视图渲染的结果
 42*/ 43public function afterRender($viewFile, $params, &$output)
 44    {
 45if ($this->hasEventHandlers(self::EVENT_AFTER_RENDER)) {//判断[EVENT_AFTER_RENDER]事件是否存在 46             $event = new ViewEvent([
 47'viewFile' => $viewFile,
 48'params' => $params,
 49'output' => $output,
 50            ]);
 51//触发[EVENT_AFTER_RENDER]事件 52             $this->trigger(self::EVENT_AFTER_RENDER, $event);
 53             $output = $event->output;//返回结果 54        }
 55    }
 56 57/**
 58     * Renders a view file as a PHP script.
 59     * 返回一个视图文件当作PHP脚本
 60     * This method treats the view file as a PHP script and includes the file.
 61     * It extracts the given parameters and makes them available in the view file.
 62     * The method captures the output of the included view file and returns it as a string.
 63     * 将传入的参数转换为变量，包含并执行view文件，返回执行结果
 64     * This method should mainly be called by view renderer or [[renderFile()]].
 65     *
 66     * @param string $_file_ the view file. 视图文件
 67     * @param array $_params_ the parameters (name-value pairs) that will be extracted and made available in the view file.
 68     * @return string the rendering result 执行结果
 69*/ 70public function renderPhpFile($_file_, $_params_ = [])
 71    {
 72         ob_start(); //打开输出缓冲 73         ob_implicit_flush(false); //关闭缓冲区 74         extract($_params_, EXTR_OVERWRITE);// 将一个数组转换为变量使用 75        require($_file_);
 76 77return ob_get_clean();//得到缓冲区的内容并清除当前输出缓冲 78    }
 79 80/**
 81     * Renders dynamic content returned by the given PHP statements. 渲染动态内容
 82     * This method is mainly used together with content caching (fragment caching and page caching)
 83     * 用来聚合缓存的内容
 84     * when some portions of the content (called *dynamic content*) should not be cached.
 85     * The dynamic content must be returned by some PHP statements.
 86     * 渲染某些被PHP语句返回的动态内容
 87     * @param string $statements the PHP statements for generating the dynamic content.生成动态内容的PHP语句。
 88     * @return string the placeholder of the dynamic content, or the dynamic content if there is no
 89     * active content cache currently. 动态内容占位符 如果当前没有有效的内容缓存，调用evaluateDynamicContent输出
 90*/ 91public function renderDynamic($statements)
 92    {
 93if (!empty($this->cacheStack)) {//动态内容的列表不为空 94             $n = count($this->dynamicPlaceholders);//统计动态内容条数 95             $placeholder = "";//生成占位符 96             $this->addDynamicPlaceholder($placeholder, $statements);//添加动态内容占位符 97 98return $placeholder;
 99         } else {//没有有效缓存 执行传入的PHP语句，返回执行结果100return $this->evaluateDynamicContent($statements);
101        }
102    }
103104/**
105     * Adds a placeholder for dynamic content. 添加一个动态内容占位符
106     * This method is internally used. 内部使用
107     * @param string $placeholder the placeholder name 占位符名称
108     * @param string $statements the PHP statements for generating the dynamic content
109     * 生成动态内容的PHP语句
110*/111public function addDynamicPlaceholder($placeholder, $statements)
112    {
113foreach ($this->cacheStack as $cache) {
114             $cache->dynamicPlaceholders[$placeholder] = $statements;//添加动态内容占位符115        }
116         $this->dynamicPlaceholders[$placeholder] = $statements;//给当前视图添加动态内容占位符117    }
118119/**
120     * Evaluates the given PHP statements. 给定的PHP语句的值
121     * This method is mainly used internally to implement dynamic content feature.内部使用实现动态内容功能
122     * @param string $statements the PHP statements to be evaluated. PHP语句进行计算
123     * @return mixed the return value of the PHP statements. PHP语句的值
124*/125public function evaluateDynamicContent($statements)
126    {
127return eval($statements);
128    }
129130/**
131     * Begins recording a block.
132     * This method is a shortcut to beginning [[Block]]
133     * 数据块开始的标记，该方法是开始[Block]的快捷方式
134     * 数据块可以在一个地方指定视图内容在另一个地方显示，通常和布局一起使用
135     * @param string $id the block ID. 数据块标识
136     * @param boolean $renderInPlace whether to render the block content in place. 是否渲染块内容。
137     * Defaults to false, meaning the captured block will not be displayed.
138     * @return Block the Block widget instance 数据块部件实例
139*/140public function beginBlock($id, $renderInPlace = false)
141    {
142return Block::begin([
143'id' => $id,//数据块唯一标识144'renderInPlace' => $renderInPlace,//是否显示标识145'view' => $this,
146        ]);
147    }
148149/**
150     * Ends recording a block. 数据块结束标识
151*/152public function endBlock()
153    {
154        Block::end();
155    }
156157/**
158     * Begins the rendering of content that is to be decorated by the specified view.
159     * This method can be used to implement nested layout. For example, a layout can be embedded
160     * in another layout file specified as '@app/views/layouts/base.php' like the following:
161     * 开始指定的view渲染内容，用来实现嵌套布局，传入的第一个参数为布局文件的路径
162     * ~~~
163     * beginContent('@app/views/layouts/base.php'); ?>
164     * ...layout content here...
165     * endContent(); ?>
166     * ~~~
167     *
168     * @param string $viewFile the view file that will be used to decorate the content enclosed by this widget.
169     * This can be specified as either the view file path or path alias.布局文件的路径或路径别名。
170     * @param array $params the variables (name => value) to be extracted and made available in the decorative view.
171     * 可以在视图中运用的参数
172     * @return ContentDecorator the ContentDecorator widget instance 部件实例
173     * @see ContentDecorator
174*/175public function beginContent($viewFile, $params = [])
176    {
177return ContentDecorator::begin([
178'viewFile' => $viewFile,
179'params' => $params,
180'view' => $this,
181        ]);
182    }
183184/**
185     * Ends the rendering of content.结束渲染内容
186*/187public function endContent()
188    {
189        ContentDecorator::end();
190    }
191192/**
193     * Begins fragment caching. 开始片段缓存
194     * This method will display cached content if it is available.
195     * If not, it will start caching and would expect an [[endCache()]]
196     * call to end the cache and save the content into cache.
197     * 展示可用的缓存内容，否则将开始缓存内容直到出现[endCache()]方法
198     * A typical usage of fragment caching is as follows,
199     *
200     * ~~~
201     * if ($this->beginCache($id)) {
202     *     // ...generate content here
203     *     $this->endCache();
204     * }
205     * ~~~
206     *
207     * @param string $id a unique ID identifying the fragment to be cached.缓存片段的唯一标识
208     * @param array $properties initial property values for [[FragmentCache]]初始属性[FragmentCache]
209     * @return boolean whether you should generate the content for caching. 是否生成缓存的内容。
210     * False if the cached version is available.
211*/212public function beginCache($id, $properties = [])
213    {
214         $properties['id'] = $id;    //片段标识215         $properties['view'] = $this;    //调用初始化属性216/* @var $cache FragmentCache */217         $cache = FragmentCache::begin($properties); 
218if ($cache->getCachedContent() !== false) {
219             $this->endCache();//从缓存中读取到了缓存的内容，则渲染内容并返回 false，不再进行缓存220221returnfalse;
222         } else {
223returntrue;
224        }
225    }
226227/**
228     * Ends fragment caching. 结束片段缓存
229*/230public function endCache()
231    {
232        FragmentCache::end();
233    }
234235/**
236     * Marks the beginning of a page.页面开始标记
237*/238public function beginPage()
239    {
240         ob_start(); //打开输出缓冲241         ob_implicit_flush(false);//关闭缓冲区242243         $this->trigger(self::EVENT_BEGIN_PAGE);
244    }
245246/**
247     * Marks the ending of a page. 页面结束标记
248*/249public function endPage()
250    {
251         $this->trigger(self::EVENT_END_PAGE);
252         ob_end_flush();//关闭输出缓冲区253     }

以上就介绍了android源码学习 yii2源码学习笔记十九），包括了android源码学习方面的内容，希望对PHP教程有兴趣的朋友有所帮助。