Yii2 source code learning notes (20), yii2 source code learning notes

Yii2 source code learning notes (20), yii2 source code learning notes

Widget class is the base class of all components. Yii2 \ base \ Widget. php

1 <? Php 2/*** @ link http://www.yiiframework.com/4 * @ copyright Copyright (c) 2008 Yii Software LLC 5 * @ license http://www.yiiframework.com/license/ 6 */7 8 namespace yii \ base; 9 10 use Yii; 11 use ReflectionClass; 12 13/** 14 * Widget is the base class for widgets. 15 * widgets are the base class of all widgets 16 * @ property string $ id of the Widget. widget ID 17 * @ property \ yii \ web \ View $ view The view object that can Be used to render views or view files. note that the 18 * type of this property differs in getter and setter. see [[getView ()] and [[setView ()] for details. 19 * view objects used to render views or view files are different in getter and setter 20 * @ property string $ viewPath The directory containing the view files for this widget. this property is 21 * read-only. view File directory containing this control 22*23 * @ author Qiang Xue <qiang.xue@gmail.com> 24 * @ since 2.0 25 */26 class Widget extends Component implements ViewContextInterface 27 {28/** 29 * @ var integer a counter used to generate [[id] for widgets. 30 * @ internal: counter 31 */32 public static $ counter = 0; 33/** 34 * @ var string the prefix to the automatically generated widget IDs. 35 * @ see getId () automatically generated prefix 36 */37 public static $ autoIdPrefix = 'W'; 38/** 39 * @ var Widget [] Widgets that are currently being rendered (not ended ). this property 40 * is maintained by [[begin ()] and [[end ()] methods. currently the rendered widget is 41 * @ internal 42 */43 public static $ stack = []; 44 45 46/** 47 * Begins a widget. start a part 48 * This method creates an instance of the calling class. it will apply the configuration 49 * to the created instance. A matching [[end ()] call shoshould be called later. 50 * Create an instance of the call class from the application configuration file, and [end ()] the method corresponds to 51 * @ param array $ config name-value pairs that will be used to initialize the object properties 52 * parameter 53 * @ return static the newly created widget instance static newly created part instance 54 */55 public static function begin ($ config = []) 56 {57 $ config ['class'] = get_called_class (); // The Name Of The static binding class in the later stage. 58/* @ var $ widget Widget */59 $ widget = Yii :: createObject ($ config); // pass the class Name and input configuration, instantiate call class 60 static: $ stack [] = $ widget; // put the object into the rendered part stack 61 62 return $ widget; 63} 64 65/** 66 * Ends a widget. end widget 67 * Note that the rendering result of the widget is directly echoed out. the rendering result is directly echoed 68 * @ return static the widget instance that is ended. static end part instance. 69 * @ throws InvalidCallException if [[begin ()] and [[end ()] CILS are not properly nested 70 */71 public static function end () 72 {73 if (! Empty (static: $ stack) {// The Calling class instance 74 $ widget = array_pop (static ::$ stack) exists in the rendered widget stack ); // Delete the last instance from the stack 75 if (get_class ($ widget) === get_called_class () {76 echo $ widget-> run (); // If the deleted instance class name and the current call class name are the same, the output widget's content 77 return $ widget; 78} else {79 throw new InvalidCallException ("Expecting end () of ". get_class ($ widget ). ", found ". get_called_class (); 80} 81} else {82 throw new InvalidCallException (" Unexpected ". get_called_class (). ': end () call. A matching begin () is not found. '); 83} 84} 85 86/** 87 * Creates a widget instance and runs it. create a part instance and run 88 * The widget rendering result is returned by this method. returns the part rendering result. 89 * @ param array $ config name-value pairs that will be used to initialize the object properties 90 * parameter 91 * @ return string the rendering result of the widget used to initialize the object properties. control rendering result. 92 */93 public static function widget ($ config = []) 94 {95 ob_start (); // open the output buffer 96 ob_implicit_flush (false ); // close the absolute refresh 97/* @ var $ widget Widget */98 $ config ['class'] = get_called_class (); // obtain the call class name 99 $ widget = Yii: createObject ($ config); // instantiate class 100 $ out = $ widget-> run (); // run part 101 102 return ob_get_clean (). $ out; // return the content of the internal buffer, disable buffer 103} 104 105 private $ _ id; 106 107/** 108 * Returns the ID of th E widget. returns the plug-in ID 109 * @ param boolean $ autoGenerate whether to generate an ID if it is not set previusly110 * whether to generate a unique ID, if 111 * @ return string ID of the widget is not set. unique part id 112 */113 public function getId ($ autoGenerate = true) 114 {115 if ($ autoGenerate & $ this-> _ id = null) {116 // If the id is empty and is set to allow automatic generation of the id, 117 $ this-> _ id = static: $ autoIdPrefix is automatically generated. static: $ counter ++; 118} 119 120 return $ this-> _ id; 121} 122 123/** 124 * Sets the ID of the widget. Set the widget id 125 * @ param string $ value ID of the widget. the widget id. 126 */127 public function setId ($ value) 128 {129 $ this-> _ id = $ value; 130} 131 132 private $ _ view; 133 134/** 135 * Returns the view object that can be used to render views or view files. returns The view object 136 * the [[render ()] and [[renderFile ()] methods will use137 * this view object to implement The actual view rendering.138 * [render ()] and the [renderFile ()] method use the view object to display the actual view. 139 * If not set, it will default to the "view" application component.140 * @ return \ yii \ web \ View the view object that can be used to render views or view files.141 */142 public function getView () 143 {144 if ($ this-> _ view = null) {145 $ this-> _ view = Yii: $ app-> getView (); // if the view object is empty, call getView () to obtain the view object instance 146} 147 148 return $ this-> _ view; 149} 150 151/** 152 * Sets the view object to be used by this wid Get. set the View object instance called by the current part 153 * @ param view $ view the view object that can be used to render views or view files.154 */155 public function setView ($ View) 156 {157 $ this-> _ view = $ view; // view object to use 158} 159 160/** 161 * Executes the widget. execute part 162 * @ return string the result of widget execution to be outputted.163. 164 */165 public function run () 166 {167} 168 169/** 170 * Renders a view.171 * The view to be rendered can be specified in one of the following formats: 172 * rendering a View that actually calls the method of rendering with the same name in the View class. You can specify the path 173 *-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 will be 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 will be looked for under the [Module :: viewPath | view path] of the currently178 * active module.179 *-relative path (e.g. "index"): the actual view file will be looked for under [[viewPath]. 180*181 * If the view name does not contain a file extension, it will use the default one '. php '. 182*183 * @ param string $ view the view name. view name 184 * @ param array $ params the parameters (name-value pairs) that shoshould be made available in the view.185 * parameter available in the view 186 * @ return string the rendering result. rendering result 187 * @ throws InvalidParamException if the view file does not exist.188 */189 public function render ($ view, $ params = []) 190 {191 // call render in the view class to render the specified view 192 return $ this-> getView ()-> render ($ view, $ params, $ this ); 193} 194 195/** 196 * Renders a view file. rendering a view file is the same as 197 * @ param string $ file the view file to be rendered. this can be either a file path or a path alias.198 * @ param array $ params the parameters (name-value pairs) that shoshould be made available in the view.199 * @ return string the rendering result.200 * @ throws InvalidParamException if the view file does not exist.201 */202 public function renderFile ($ file, $ params = []) 203 {204 return $ this-> getView ()-> renderFile ($ file, $ params, $ this ); 205} 206 207/** 208 * Returns the directory containing the view files for this widget. return to The view File Path 209 * the default implementation returns the 'view' subdirectory under the directory containing the widget class file.210 * @ return string the directory containing The view files for this widget.211 */212 public function getViewPath () 213 {214 $ class = new ReflectionClass ($ this); 215 // obtain the directory of the part class file and splice it into the view directory 216 return dirname ($ class-> getFileName ()). DIRECTORY_SEPARATOR. 'Views '; 217} 218}