Android Source Learning yii2 Source Learning Note 20)

The Widget class is the base class for all parts. yii2\base\widget.php

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 Php2/**3* @linkhttp://www.yiiframework.com/4* @copyright Copyright (c) Yii software LLC5* @licensehttp://www.yiiframework.com/license/6*/78namespaceYii\Base;9TenUse Yii; OneUse reflectionclass; A -/** -* Widgets are the base class for widgets. the* Widget is the base class for all widgets -* @property string $id ID of the widget. Widget Identification -* @property \yii\web\view $view The "View object" can used to render views or View files. Note that the -* Type of this property differs in getter and setter. see [[GetView ()]] and [[Setview () ]] for details. +* The View object used to render the view or view file is different in getter and setter -* @property string $viewPath The directory containing the view files for this widget. This property is +* read-only. The view file directory that contains this control A * at* @author Qiang Xue 
     -* @since 2.0 -*/ -classWidget extends Component implements Viewcontextinterface -{ -/** in* @var integer a counter used to generate [[ID]] for widgets. -* @internal counters for generating widget IDs to*/ + PublicStatic$counter =0; -/** the* @var string The prefix to the automatically generated widget IDs. ** @see getId () auto-generated prefixes $*/Panax Notoginseng PublicStatic$autoIdPrefix ='W'; -/** the* @var widget[] The widgets that is currently being rendered (not ended). this property +* is maintained by [[begin ()]] and [[end ()]] methods. Widgets currently being rendered A* @internal the*/ + PublicStatic$stack = []; - $ $/** -* begins a widget. Start a part -* This method creates a instance of the calling class. It'll apply the configuration the* to the created instance. A matching [[end ()]] call should is called later. -* Create an instance of the calling class from the application configuration file, corresponding to the [end ()] Square methodWuyi* @param array $config name-value pairs that'll be used to initialize the object properties the* Parameters for initializing properties -* @return Static the newly created widget instance a newly created part instance Wu*/ - PublicStaticfunction begin ($config = []) About    { $$config ['class'] = Get_called_class ();//name of late static binding class -/*@var $widget Widgets*/ -$widget = Yii::createobject ($config);//instantiating the calling class through the class name and the incoming configuration -Static:: $stack [] = $widget;//Placing an object in the part stack that is being rendered A +return$widget; the    } - $/** the* Ends a widget. End Widget the* Note that the rendering result of the widget was directly echoed out. Rendering results are directly echoed the* @return Static The widget instance that is ended. Static end of the part instance.  the* @throws invalidcallexception if [[begin ()]] and [[End () ]] calls is not properly nested -*/ in PublicStaticfunction End () the    { theif(!empty (Static:: $stack)) {//invoking class instance exists in the rendered widget stack About$widget = Array_pop (Static:: $stack);//Remove the last instance from the stack theif(Get_class ($widget) = = =Get_called_class ()) { theecho $widget->run ();//If the deleted instance class name and the current calling class name are the same, the contents of the output widget thereturn$widget; +}Else { -ThrowNewInvalidcallexception ("expecting end () of". Get_class ($widget).", found". Get_called_class ()); the            }Bayi}Else { theThrowNewInvalidcallexception ("unexpected". Get_called_class ().':: End () call. A matching begin () is not found.'); the        } -    } - the/** the* Creates a widget instance and runs it. Create a part instance and run the* The widget rendering result is a returned by this method. Returns the result of the part rendering.  the* @param array $config name-value pairs that'll be used to initialize the object properties -* Parameters for initializing object Properties the* @return String The rendering result of the widget. Render results for the control.  the*/ the PublicStaticFunction Widget ($config = [])94    { theOb_start ();//Open Output Buffers theOb_implicit_flush (false);//Turn off absolute refresh the/*@var $widget Widgets*/98$config ['class'] = Get_called_class ();//gets the class name of the calling class About$widget = Yii::createobject ($config);//Instantiating Classes -$ out= $widget->run ();//Running Parts101102returnOb_get_clean (). $ out;//returns the contents of the internal buffer, closing the buffer103    }104 thePrivate$_id;106107/**108* Returns The ID of the widget. Returns the identity of the plug-in109* @param boolean $autoGenerate whether to generate an ID if it's not set previously the* Whether to generate a unique identity if not set111* @return string ID of the widget. Part Unique identification the*/113 Publicfunction GetId ($autoGenerate =true) the    { theif($autoGenerate && $ This->_id = = =NULL) { the//automatically generated if the identity is empty and is set to allow automatic generation of identities117$ This->_id =Static:: $autoIdPrefix.Static:: $counter + +;118        }119 -return$ This-_id;121    }122123/**124* Sets the ID of the widget. Setting the widget ID the* @param string $value ID of the widget. 126*/127 Publicfunction SetId ($value) -    {129$ This->_id =$value; the    }131 thePrivate$_view;133134/**135* Returns The View object that can is used to render views or view files. Return to view objects136* The [[Render ()]] and [[RenderFile () ]] methods'll use137* This view is object to implement the actual view rendering.138* [Render ()] and [RenderFile ()] methods implement the actual view display with the View object. 139* If not set, it would default to the "View" application component. $* @return \yii\web\view The View object, can be used to render views or View files.141*/142 Publicfunction GetView ()143    {144if($ This->_view = = =NULL) {145$ This->_view = Yii:: $app->getview ();//call GetView () to get the View object instance if the View object is empty146        }147148return$ This-_view;149    } Max151/** the* Sets the View object to being used by this widget. Set instance of view objects called by the current part153* @param view $view The View object, can be used to render views or View files.154*/155 Publicfunction Setview ($view)156    {157$ This->_view = $view;//the View object to use158    }159 the/**161* Executes the widget. Actuator Parts162* @return String The result of widget execution to be outputted.163* The result output of the control execution. 164*/165 Publicfunction Run ()166    {167    }168169/** the* Renders a view.171* The view to is rendered can specified in one of the following formats:172* Render a view actually calling a view in the view class rendered with the same name method can specify the path in the following ways173*-Path alias (e.g. "@app/views/site/index");174*-Absolute path within application (e.g. "//site/index"): The view name starts with double slashes.175* The actual view file is looked for under the [[Application::viewpath|view Path]] of the APPLICATION.176*-Absolute path within module (e.g. "/site/index"): The view name starts with a single slash.177* The actual view file is looked for under the [[Module::viewpath|view Path]] of the currently178* Active module.179*-relative path (e.g. "index"): The actual view file is looked for under [[ViewPath]]. the     *181* If The view name does not contain a file extension, it'll use the default one '. php '.182     *183* @param string $view the view name. View name184* @param array $params The parameters (Name-value pairs) that should is made available in the view.185* Parameters available in the View186* @return string The rendering result. Render Results187* @throws invalidparamexception If the view file does not exist.188*/189 Publicfunction Render ($view, $params= []) the    {191//call render render in the view class for the specified view192return$ This->getview ()->render ($view, $params, $ This);193    }194195/**196* Renders a view file.197* @param string $file The view file to be rendered. This can is either a file path or a path alias.198* @param array $params The parameters (Name-value pairs) that should is made available in the view.199* @return string The rendering result. $* @throws invalidparamexception If the view file does not exist.201*/202 Publicfunction RenderFile ($file, $params= [])203    {204return$ This->getview ()->renderfile ($file, $params, $ This);205    }206207/**208* Returns The directory containing the view files for this widget. Returns the view file path209* The default implementation returns the ' views ' subdirectory under the directory containing the Widget class Fil E. About* @return String The directory containing the view files for this widget.211*/212 Publicfunction Getviewpath ()213    {214$class=NewReflectionclass ($ This);215//get the directory of the part class file, stitching it into the view directory216returnDirName ($class->getfilename ()). Directory_separator.' views';217    }218}

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