视图助手(View Helpers) ======================== Writing and maintaining HTML markup can quickly become a tedious task because of the naming conventions and numerous attributes that have to be taken into consideration. Phalcon deals with this complexity by offering :doc:`Phalcon\\Tag <../api/Phalcon_Tag>`, which in turn offers view helpers to generate HTML markup. This component can be used in a plain HTML+PHP view or in a :doc:`Volt ` template. .. highlights:: This guide is not intended to be a complete documentation of available helpers and their arguments. Please visit the :doc:`Phalcon\\Tag <../api/Phalcon_Tag>` page in the API for a complete reference. 文档类型(Document Type of Content) ------------------------------------ Phalcon provides :code:`Phalcon\Tag::setDoctype()` helper to set document type of the content. Document type setting may affect HTML output produced by other tag helpers. For example, if you set XHTML document type family, helpers that return or output HTML tags will produce self-closing tags to follow valid XHTML standard. Available document type constants in :doc:`Phalcon\\Tag <../api/Phalcon_Tag>` namespace are: +----------------------+------------------------+ | Constant | Document type | +======================+========================+ | HTML32 | HTML 3.2 | +----------------------+------------------------+ | HTML401_STRICT | HTML 4.01 Strict | +----------------------+------------------------+ | HTML401_TRANSITIONAL | HTML 4.01 Transitional | +----------------------+------------------------+ | HTML401_FRAMESET | HTML 4.01 Frameset | +----------------------+------------------------+ | HTML5 | HTML 5 | +----------------------+------------------------+ | XHTML10_STRICT | XHTML 1.0 Strict | +----------------------+------------------------+ | XHTML10_TRANSITIONAL | XHTML 1.0 Transitional | +----------------------+------------------------+ | XHTML10_FRAMESET | XHTML 1.0 Frameset | +----------------------+------------------------+ | XHTML11 | XHTML 1.1 | +----------------------+------------------------+ | XHTML20 | XHTML 2.0 | +----------------------+------------------------+ | XHTML5 | XHTML 5 | +----------------------+------------------------+ Setting document type. .. code-block:: php tag->setDoctype(Tag::HTML401_STRICT); ?> Getting document type. .. code-block:: html+php tag->getDoctype() ?> The following HTML will be produced. .. code-block:: html Volt syntax: .. code-block:: html+jinja {{ get_doctype() }} 生成链接(Generating Links) ---------------------------- A real common task in any web application or website is to produce links that allow us to navigate from one page to another. When they are internal URLs we can create them in the following manner: .. code-block:: html+php tag->linkTo("products/search", "Search") ?> tag->linkTo(array('products/edit/10', 'Edit', 'class' => 'edit-btn')) ?> tag->linkTo(array(array('for' => 'show-product', 'title' => 123, 'name' => 'carrots'), 'Show')) ?> Actually, all produced URLs are generated by the component :doc:`Phalcon\\Mvc\\Url ` (or service "url" failing) Same links generated with Volt: .. code-block:: html+jinja {{ link_to("products/search", "Search") }} {{ link_to(['for': 'show-product', 'id': 123, 'name': 'carrots'], 'Show') }} {{ link_to(['for': 'show-product', 'id': 123, 'name': 'carrots'], 'Show', 'class': 'edit-btn') }} 创建表单(Creating Forms) -------------------------- Forms in web applications play an essential part in retrieving user input. The following example shows how to implement a simple search form using view helpers: .. code-block:: html+php tag->form("products/search") ?> tag->textField("q") ?> tag->submitButton("Search") ?> tag->endForm() ?> tag->form(array("products/search", "method" => "get")); ?> tag->textField("q"); ?> tag->submitButton("Search"); ?> tag->endForm() ?> This last code will generate the following HTML: .. code-block:: html
Same form generated in Volt: .. code-block:: html+jinja {{ form("products/search", "method": "get") }} {{ text_field("q") }} {{ submit_button("Search") }} {{ endForm() }} Phalcon also provides a :doc:`form builder ` to create forms in an object-oriented manner. 使用助手生成表单控件(Helpers to Generate Form Elements) --------------------------------------------------------- Phalcon provides a series of helpers to generate form elements such as text fields, buttons and more. The first parameter of each helper is always the name of the element to be generated. When the form is submitted, the name will be passed along with the form data. In a controller you can get these values using the same name by using the :code:`getPost()` and :code:`getQuery()` methods on the request object (:code:`$this->request`). .. code-block:: html+php tag->textField("username") ?> tag->textArea(array( "comment", "This is the content of the text-area", "cols" => "6", "rows" => 20 )) ?> tag->passwordField(array( "password", "size" => 30 )) ?> tag->hiddenField(array( "parent_id", "value"=> "5" )) ?> Volt syntax: .. code-block:: html+jinja {{ text_field("username") }} {{ text_area("comment", "This is the content", "cols": "6", "rows": 20) }} {{ password_field("password", "size": 30) }} {{ hidden_field("parent_id", "value": "5") }} 使用选择框(Making Select Boxes) --------------------------------- Generating select boxes (select box) is easy, especially if the related data is stored in PHP associative arrays. The helpers for select elements are :code:`Phalcon\Tag::select()` and :code:`Phalcon\Tag::selectStatic()`. :code:`Phalcon\Tag::select()` has been was specifically designed to work with :doc:`Phalcon\\Mvc\\Model `, while :code:`Phalcon\Tag::selectStatic()` can with PHP arrays. .. code-block:: php tag->select( array( "productId", Products::find("type = 'vegetables'"), "using" => array("id", "name") ) ); // Using data from an array echo $this->tag->selectStatic( array( "status", array( "A" => "Active", "I" => "Inactive", ) ) ); The following HTML will generated: .. code-block:: html You can add an "empty" option to the generated HTML: .. code-block:: php tag->select( array( "productId", Products::find("type = 'vegetables'"), "using" => array("id", "name"), "useEmpty" => true ) ); Produces this HTML: .. code-block:: html .. code-block:: php tag->select( array( 'productId', Products::find("type = 'vegetables'"), 'using' => array('id', "name"), 'useEmpty' => true, 'emptyText' => 'Please, choose one...', 'emptyValue' => '@' ) ); .. code-block:: html Volt syntax for above example: .. code-block:: jinja {# Creating a Select Tag with an empty option with default text #} {{ select('productId', products, 'using': ['id', 'name'], 'useEmpty': true, 'emptyText': 'Please, choose one...', 'emptyValue': '@') }} 设置 HTML 属性(Assigning HTML attributes) ------------------------------------------- All the helpers accept an array as their first parameter which can contain additional HTML attributes for the element generated. .. code-block:: html+php tag->textField( array( "price", "size" => 20, "maxlength" => 30, "placeholder" => "Enter a price" ) ) ?> or using Volt: .. code-block:: jinja {{ text_field("price", "size": 20, "maxlength": 30, "placeholder": "Enter a price") }} The following HTML is generated: .. code-block:: html 设置助手的值(Setting Helper Values) ------------------------------------- 通过控制器(From Controllers) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ It is a good programming principle for MVC frameworks to set specific values for form elements in the view. You can set those values directly from the controller using :code:`Phalcon\Tag::setDefault()`. This helper preloads a value for any helpers present in the view. If any helper in the view has a name that matches the preloaded value, it will use it, unless a value is directly assigned on the helper in the view. .. code-block:: php tag->setDefault("color", "Blue"); } } At the view, a selectStatic helper matches the same index used to preset the value. In this case "color": .. code-block:: php tag->selectStatic( array( "color", array( "Yellow" => "Yellow", "Blue" => "Blue", "Red" => "Red" ) ) ); This will generate the following select tag with the value "Blue" selected: .. code-block:: html 通过请求(From the Request) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ A special feature that the :doc:`Phalcon\\Tag <../api/Phalcon_Tag>` helpers have is that they keep the values of form helpers between requests. This way you can easily show validation messages without losing entered data. 直接设置值(Specifying values directly) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Every form helper supports the parameter "value". With it you can specify a value for the helper directly. When this parameter is present, any preset value using setDefault() or via request will be ignored. 动态设置文档标题(Changing dynamically the Document Title) ----------------------------------------------------------- :doc:`Phalcon\\Tag <../api/Phalcon_Tag>` offers helpers to change dynamically the document title from the controller. The following example demonstrates just that: .. code-block:: php tag->setTitle("Your Website"); } public function indexAction() { $this->tag->prependTitle("Index of Posts - "); } } .. code-block:: html+php tag->getTitle(); ?> The following HTML will generated: .. code-block:: html+php Index of Posts - Your Website 静态内容助手(Static Content Helpers) -------------------------------------- :doc:`Phalcon\\Tag <../api/Phalcon_Tag>` also provide helpers to generate tags such as script, link or img. They aid in quick and easy generation of the static resources of your application 图片(Images) ^^^^^^^^^^^^^^ .. code-block:: php echo $this->tag->image("img/hello.gif"); // Generate alternative text echo $this->tag->image( array( "img/hello.gif", "alt" => "alternative text" ) ); Volt syntax: .. code-block:: jinja {# Generate #} {{ image("img/hello.gif") }} {# Generate alternative text #} {{ image("img/hello.gif", "alt": "alternative text") }} 样式表(Stylesheets) ^^^^^^^^^^^^^^^^^^^^^ .. code-block:: php echo $this->tag->stylesheetLink("http://fonts.googleapis.com/css?family=Rosario", false); // Generate echo $this->tag->stylesheetLink("css/styles.css"); Volt syntax: .. code-block:: jinja {# Generate #} {{ stylesheet_link("http://fonts.googleapis.com/css?family=Rosario", false) }} {# Generate #} {{ stylesheet_link("css/styles.css") }} 脚本(Javascript) ^^^^^^^^^^^^^^^^^^ .. code-block:: php echo $this->tag->javascriptInclude("http://localhost/javascript/jquery.min.js", false); // Generate echo $this->tag->javascriptInclude("javascript/jquery.min.js"); Volt syntax: .. code-block:: jinja {# Generate #} {{ javascript_include("http://localhost/javascript/jquery.min.js", false) }} {# Generate #} {{ javascript_include("javascript/jquery.min.js") }} HTML5 对象(HTML5 elements - generic HTML helper) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Phalcon offers a generic HTML helper that allows the generation of any kind of HTML element. It is up to the developer to produce a valid HTML element name to the helper. .. code-block:: php // This is my canvas // echo $this->tag->tagHtml("canvas", array("id" => "canvas1", "width" => "300", "class" => "cnvclass"), false, true, true); echo "This is my canvas"; echo $this->tag->tagHtmlClose("canvas"); Volt syntax: .. code-block:: html+jinja {# Generate This is my canvas #} {{ tag_html("canvas", ["id": "canvas1", width": "300", "class": "cnvclass"], false, true, true) }} This is my canvas {{ tag_html_close("canvas") }} 标签服务(Tag Service) ----------------------- :doc:`Phalcon\\Tag <../api/Phalcon_Tag>` is available via the 'tag' service, this means you can access it from any part of the application where the services container is located: .. code-block:: php tag->linkTo('pages/about', 'About') ?> You can easily add new helpers to a custom component replacing the service 'tag' in the services container: .. code-block:: php ` and implement your own helper. Below is a simple example of a custom helper: .. code-block:: php $attributeValue) { if (!is_integer($key)) { $code.= $key.'="'.$attributeValue.'" '; } } $code.=" />"; return $code; } } After creating our custom helper, we will autoload the new directory that contains our helper class from our "index.php" located in the public directory. .. code-block:: php registerDirs(array( '../app/controllers', '../app/models', '../app/customhelpers' // Add the new helpers folder ))->register(); $di = new FactoryDefault(); // Assign our new tag a definition so we can call it $di->set('MyTags', function () { return new MyTags(); }); $application = new Application($di); echo $application->handle()->getContent(); } catch (PhalconException $e) { echo "PhalconException: ", $e->getMessage(); } Now you are ready to use your new helper within your views: .. code-block:: php 'test', 'id' => 'audio_test', 'src' => '/path/to/audio.mp3' ) ); ?> In next chapter, we'll talk about :doc:`Volt ` a faster template engine for PHP, where you can use a more friendly syntax for using helpers provided by :doc:`Phalcon\\Tag <../api/Phalcon_Tag>`.