PHP Element::isEmpty方法代码示例

 /**
  * #pre_render callback for building a block.
  *
  * Renders the content using the provided block plugin, and then:
  * - if there is no content, aborts rendering, and makes sure the block won't
  *   be rendered.
  * - if there is content, moves the contextual links from the block content to
  *   the block itself.
  */
 public function buildBlock($build)
 {
     $content = $build['#block']->getPlugin()->build();
     // Remove the block entity from the render array, to ensure that blocks
     // can be rendered without the block config entity.
     unset($build['#block']);
     if ($content !== NULL && !Element::isEmpty($content)) {
         // Place the $content returned by the block plugin into a 'content' child
         // element, as a way to allow the plugin to have complete control of its
         // properties and rendering (e.g., its own #theme) without conflicting
         // with the properties used above, or alternate ones used by alternate
         // block rendering approaches in contrib (e.g., Panels). However, the use
         // of a child element is an implementation detail of this particular block
         // rendering approach. Semantically, the content returned by the plugin
         // "is the" block, and in particular, #attributes and #contextual_links is
         // information about the *entire* block. Therefore, we must move these
         // properties from $content and merge them into the top-level element.
         foreach (array('#attributes', '#contextual_links') as $property) {
             if (isset($content[$property])) {
                 $build[$property] += $content[$property];
                 unset($content[$property]);
             }
         }
         $build['content'] = $content;
     } else {
         // Abort rendering: render as the empty string and ensure this block is
         // render cached, so we can avoid the work of having to repeatedly
         // determine whether the block is empty. E.g. modifying or adding entities
         // could cause the block to no longer be empty.
         $build = array('#markup' => '', '#cache' => $build['#cache']);
         // If $content is not empty, then it contains cacheability metadata, and
         // we must merge it with the existing cacheability metadata. This allows
         // blocks to be empty, yet still bubble cacheability metadata, to indicate
         // why they are empty.
         if (!empty($content)) {
             CacheableMetadata::createFromRenderArray($build)->merge(CacheableMetadata::createFromRenderArray($content))->applyTo($build);
         }
     }
     return $build;
 }

 /**
  * {@inheritdoc}
  */
 public function build()
 {
     // Get block
     $block = $this->getBlock();
     // Apply block config.
     $block_config = $this->blockConfig();
     $block->setConfiguration($block_config);
     // Get render array.
     $block_elements = $block->build();
     // Return an empty array if there is nothing to render.
     return Element::isEmpty($block_elements) ? [] : $block_elements;
 }

 /**
  * Build render arrays for each of the regions.
  *
  * @param array $regions
  *   The render array representing regions.
  * @param array $contexts
  *   The array of context objects.
  *
  * @return array
  *   An associative array, keyed by region ID, containing the render arrays
  *   representing the content of each region.
  */
 protected function buildRegions(array $regions, array $contexts)
 {
     $build = [];
     foreach ($regions as $region => $blocks) {
         if (!$blocks) {
             continue;
         }
         $region_name = Html::getClass("block-region-{$region}");
         $build[$region]['#prefix'] = '<div class="' . $region_name . '">';
         $build[$region]['#suffix'] = '</div>';
         /** @var \Drupal\Core\Block\BlockPluginInterface[] $blocks */
         $weight = 0;
         foreach ($blocks as $block_id => $block) {
             if ($block instanceof ContextAwarePluginInterface) {
                 $this->contextHandler->applyContextMapping($block, $contexts);
             }
             if ($block->access($this->account)) {
                 $block_render_array = ['#theme' => 'block', '#attributes' => [], '#contextual_links' => [], '#weight' => $weight++, '#configuration' => $block->getConfiguration(), '#plugin_id' => $block->getPluginId(), '#base_plugin_id' => $block->getBaseId(), '#derivative_plugin_id' => $block->getDerivativeId()];
                 // Build the block and bubble its attributes up if possible. This
                 // allows modules like Quickedit to function.
                 // See \Drupal\block\BlockViewBuilder::preRender() for reference.
                 $content = $block->build();
                 if ($content !== NULL && !Element::isEmpty($content)) {
                     foreach (['#attributes', '#contextual_links'] as $property) {
                         if (isset($content[$property])) {
                             $block_render_array[$property] += $content[$property];
                             unset($content[$property]);
                         }
                     }
                 }
                 $block_render_array['content'] = $content;
                 $build[$region][$block_id] = $block_render_array;
             }
         }
     }
     return $build;
 }

 /**
  * #pre_render callback for building a block.
  *
  * Renders the content using the provided block plugin, if there is no
  * content, aborts rendering, and makes sure the block won't be rendered.
  */
 public function buildBlock($build)
 {
     $content = $build['#block_plugin']->build();
     // Remove the block plugin from the render array.
     unset($build['#block_plugin']);
     if ($content !== NULL && !Element::isEmpty($content)) {
         $build['content'] = $content;
     } else {
         // Abort rendering: render as the empty string and ensure this block is
         // render cached, so we can avoid the work of having to repeatedly
         // determine whether the block is empty. E.g. modifying or adding entities
         // could cause the block to no longer be empty.
         $build = ['#markup' => '', '#cache' => $build['#cache']];
     }
     // If $content is not empty, then it contains cacheability metadata, and
     // we must merge it with the existing cacheability metadata. This allows
     // blocks to be empty, yet still bubble cacheability metadata, to indicate
     // why they are empty.
     if (!empty($content)) {
         CacheableMetadata::createFromRenderArray($build)->merge(CacheableMetadata::createFromRenderArray($content))->applyTo($build);
     }
     return $build;
 }

 /**
  * Indicates whether the given element is empty.
  *
  * An element that only has #cache set is considered empty, because it will
  * render to the empty string.
  *
  * @return bool
  *   Whether the given element is empty.
  */
 public function isEmpty()
 {
     return \Drupal\Core\Render\Element::isEmpty($this->array);
 }

 /**
  * {@inheritdoc}
  */
 public function submitForm(array &$form, FormStateInterface $form_state)
 {
     // Return early if there are any errors.
     if ($form_state->hasAnyErrors()) {
         return $form;
     }
     $block_instance = $this->getBlockInstance($form_state);
     // Submit the block configuration form.
     $this->submitBlock($block_instance, $form, $form_state);
     // If a temporary configuration for this variant exists, use it.
     $temp_store_key = $this->panelsDisplay->id();
     if ($variant_config = $this->tempStore->get($temp_store_key)) {
         $this->panelsDisplay->setConfiguration($variant_config);
     }
     // Set the block region appropriately.
     $block_config = $block_instance->getConfiguration();
     $block_config['region'] = $form_state->getValue(array('settings', 'region'));
     // Determine if we need to update or add this block.
     if ($uuid = $form_state->getValue('uuid')) {
         $this->panelsDisplay->updateBlock($uuid, $block_config);
     } else {
         $uuid = $this->panelsDisplay->addBlock($block_config);
     }
     // Set the tempstore value.
     $this->tempStore->set($this->panelsDisplay->id(), $this->panelsDisplay->getConfiguration());
     // Assemble data required for our App.
     $build = $this->buildBlockInstance($block_instance);
     // Bubble block attributes up if possible. This allows modules like
     // Quickedit to function.
     // See \Drupal\block\BlockViewBuilder::preRender() for reference.
     if ($build['content'] !== NULL && !Element::isEmpty($build['content'])) {
         foreach (['#attributes', '#contextual_links'] as $property) {
             if (isset($build['content'][$property])) {
                 $build[$property] += $build['content'][$property];
                 unset($build['content'][$property]);
             }
         }
     }
     // Add our data attribute for the Backbone app.
     $build['#attributes']['data-block-id'] = $uuid;
     $block_model = ['uuid' => $uuid, 'label' => $block_instance->label(), 'id' => $block_instance->getPluginId(), 'region' => $block_config['region'], 'html' => $this->renderer->render($build)];
     $form['build'] = $build;
     // Add Block metadata and HTML as a drupalSetting.
     $form['#attached']['drupalSettings']['panels_ipe']['updated_block'] = $block_model;
     return $form;
 }

 /**
  * @covers ::isEmpty
  *
  * @dataProvider providerTestIsEmpty
  */
 public function testIsEmpty(array $element, $expected)
 {
     $this->assertSame(Element::isEmpty($element), $expected);
 }