PHP框架Laravel插件Pagination實現自定義分頁

Laravel 的分頁很方便，其實擴展起來也挺容易的，下面就來做個示例，擴展一下 paginate() 和 simplePaginate() 方法，來實現我們自定義分頁樣式，比如顯示 "上一頁" 和 "下一頁" ，而不是 "《" 和 "》" ，當然擴展的方法掌握了你就可以肆無忌憚的擴展一個你想要的分頁了，比如跳轉到某一頁，分頁顯示一共多少記錄，當前顯示的記錄范圍等等巴拉巴拉的。。。

5.1和5.2應該是同樣的方法，我這裡用的是5.2的版本。文檔告訴我們 Paginator 對應於查詢語句構造器和 Eloquent 的  simplePaginate 方法，而  LengthAwarePaginator 則等同於  paginate 方法。那我們還是來看下源碼，具體這個  paginate 是如何實現 render() 的,

Illuminate/Pagination/LengthAwarePaginator.php

<?php

namespace Illuminate\Pagination;

......

class LengthAwarePaginator extends AbstractPaginator implements Arrayable, ArrayAccess, Countable, IteratorAggregate, JsonSerializable, Jsonable, LengthAwarePaginatorContract 
{
......
  public function render(Presenter $presenter = null)
  {
    if (is_null($presenter) && static::$presenterResolver) {
      $presenter = call_user_func(static::$presenterResolver, $this);
    }

    $presenter = $presenter ?: new BootstrapThreePresenter($this);

    return $presenter->render();
  }
......
}

render() 中傳入的是一個 Presenter 的實例，並調用這個實例化的 render 方法來實現分頁的顯示的。如果沒有則調用 BootstrapThreePresenter 中 render() 的，來看看 BootstrapThreePresenter 是干嘛的

Illuminate/Pagination/BootstrapThreePresenter.php

<?php

namespace Illuminate\Pagination;

use Illuminate\Support\HtmlString; 
use Illuminate\Contracts\Pagination\Paginator as PaginatorContract; 
use Illuminate\Contracts\Pagination\Presenter as PresenterContract;

class BootstrapThreePresenter implements PresenterContract 
{
  use BootstrapThreeNextPreviousButtonRendererTrait, UrlWindowPresenterTrait;

  /**
   * The paginator implementation.
   *
   * @var \Illuminate\Contracts\Pagination\Paginator
   */
  protected $paginator;

  /**
   * The URL window data structure.
   *
   * @var array
   */
  protected $window;

  /**
   * Create a new Bootstrap presenter instance.
   *
   * @param \Illuminate\Contracts\Pagination\Paginator $paginator
   * @param \Illuminate\Pagination\UrlWindow|null $window
   * @return void
   */
  public function __construct(PaginatorContract $paginator, UrlWindow $window = null)
  {
    $this->paginator = $paginator;
    $this->window = is_null($window) ? UrlWindow::make($paginator) : $window->get();
  }

  /**
   * Determine if the underlying paginator being presented has pages to show.
   *
   * @return bool
   */
  public function hasPages()
  {
    return $this->paginator->hasPages();
  }

  /**
   * Convert the URL window into Bootstrap HTML.
   *
   * @return \Illuminate\Support\HtmlString
   */
  public function render()
  {
    if ($this->hasPages()) {
      return new HtmlString(sprintf(
        '<ul class="pagination">%s %s %s</ul>',
        $this->getPreviousButton(),
        $this->getLinks(),
        $this->getNextButton()
      ));
    }

    return '';
  }
......
}

這裡可以看到 BootstrapThreePresenter 實現了 PresenterContract 的接口， render() 才是分頁顯示的真正實現，構造方法中的第一個參數 PaginatorContract 其實就是一個 Paginator 我們繼續看下 PresenterContract 也就是 Presenter 接口中定義了什麼方法需要實現

illuminate/contracts/Pagination/Presenter.php

<?php

namespace Illuminate\Contracts\Pagination;

interface Presenter 
{
  /**
   * Render the given paginator.
   *
   * @return \Illuminate\Contracts\Support\Htmlable|string
   */
  public function render();

  /**
   * Determine if the underlying paginator being presented has pages to show.
   *
   * @return bool
   */
  public function hasPages();
}

其中定義了 render 和 hasPages 方法需要實現

好了，那我們現在已經很清晰了,我們要自定義分頁的顯示，那麼就要寫一個我們自己的 Presenter 來實現接口中的 render() 和 hasPages() 就可以了。

首先就來簡單的實現一個paginate()，顯示出來"上一頁"和"下一頁"，中間是分頁數字的例子。

新建文件如下（個人習慣）

app/Foundations/Pagination/CustomerPresenter.php

<?php 
namespace App\Foundations\Pagination;

use Illuminate\Contracts\Pagination\Presenter as PresenterContract; 
use Illuminate\Contracts\Pagination\LengthAwarePaginator as PaginatorContract; 
use Illuminate\Pagination\UrlWindow; 
use Illuminate\Support\HtmlString; 
use Illuminate\Pagination\BootstrapThreeNextPreviousButtonRendererTrait; 
use Illuminate\Pagination\UrlWindowPresenterTrait;

class CustomerPresenter implements PresenterContract 
{
  use BootstrapThreeNextPreviousButtonRendererTrait, UrlWindowPresenterTrait;

  protected $paginator;

  protected $window;

  /**
   * Create a new Bootstrap presenter instance.
   *
   * @param \Illuminate\Contracts\Pagination\Paginator $paginator
   * @param \Illuminate\Pagination\UrlWindow|null $window
   * @return void
   */
  public function __construct(PaginatorContract $paginator, UrlWindow $window = null)
  {
    $this->paginator = $paginator;
    $this->window = is_null($window) ? UrlWindow::make($paginator) : $window->get();
  }

  /**
   * Determine if the underlying paginator being presented has pages to show.
   *
   * @return bool
   */
  public function hasPages()
  {
    return $this->paginator->hasPages();
  }

  /**
   * Convert the URL window into Bootstrap HTML.
   *
   * @return \Illuminate\Support\HtmlString
   */
  public function render()
  {
    if ($this->hasPages()) {
      return new HtmlString(sprintf(
        '<ul class="pagination">%s %s %s</ul>',
        $this->getPreviousButton('上一頁'),//具體實現可以查看該方法
        $this->getLinks(),
        $this->getNextButton('下一頁')//具體實現可以查看該方法
      ));
    }

    return '';
  }

  /**
   * Get HTML wrapper for an available page link.
   *
   * @param string $url
   * @param int $page
   * @param string|null $rel
   * @return string
   */
  protected function getAvailablePageWrapper($url, $page, $rel = null)
  {
    $rel = is_null($rel) ? '' : ' rel="' . $rel . '"';

    return '<li><a href="' . htmlentities($url) . '"' . $rel . '>' . $page . '</a></li>';
  }

  /**
   * Get HTML wrapper for disabled text.
   *
   * @param string $text
   * @return string
   */
  protected function getDisabledTextWrapper($text)
  {
    return '<li class="disabled hide"><span>' . $text . '</span></li>';
  }

  /**
   * Get HTML wrapper for active text.
   *
   * @param string $text
   * @return string
   */
  protected function getActivePageWrapper($text)
  {
    return '<li class="active"><span>' . $text . '</span></li>';
  }

  /**
   * Get a pagination "dot" element.
   *
   * @return string
   */
  protected function getDots()
  {
    return $this->getDisabledTextWrapper('...');
  }

  /**
   * Get the current page from the paginator.
   *
   * @return int
   */
  protected function currentPage()
  {
    return $this->paginator->currentPage();
  }

  /**
   * Get the last page from the paginator.
   *
   * @return int
   */
  protected function lastPage()
  {
    return $this->paginator->lastPage();
  }

}

就這麼簡單，主要就是 render() 方法，如果項目中需要修改分頁樣式，或者添加分頁跳轉之類的需求只要重寫其中的各項顯示的方法中的html元素就可以了，很靈活，在blade模板中也需要修該，比如我們的 Paginator 叫 $users ,默認的分頁顯示是這樣的：

{!! $users->render() !!}
修改成我們自定義後的分頁顯示：

{!! with(new \App\Foundations\Pagination\CustomerPresenter($categories))->render() !!}
好了，這樣在頁面應該就可以看到分頁鏈接中含有 "上一頁"和"下一頁"加數字的樣式了。

那麼如果擴展simplePaginate?其實很簡單，只要繼承剛才的 CustomerPresenter ，實現 hasPages 和 render ,至於為什麼可以按照我上面查看源碼的方式看一下就知道了，比如我們改成"上一篇"和"下一篇"

新建App\Foundations\Pagination\CustomerSimplePresenter.php

<?php 
namespace App\Foundations\Pagination;


use Illuminate\Support\HtmlString; 
use Illuminate\Contracts\Pagination\Paginator as PaginatorContract;

class CustomerSimplePresenter extends CustomerPresenter 
{
  /**
   * Create a simple Bootstrap 3 presenter.
   *
   * @param \Illuminate\Contracts\Pagination\Paginator $paginator
   * @return void
   */
  public function __construct(PaginatorContract $paginator)
  {
    $this->paginator = $paginator;
  }

  /**
   * Determine if the underlying paginator being presented has pages to show.
   *
   * @return bool
   */
  public function hasPages()
  {
    return $this->paginator->hasPages() && count($this->paginator->items()) > 0;
  }

  /**
   * Convert the URL window into Bootstrap HTML.
   *
   * @return \Illuminate\Support\HtmlString
   */
  public function render()
  {
    if ($this->hasPages()) {
      return new HtmlString(sprintf(
        '<ul class="pager">%s %s</ul>',
        $this->getPreviousButton('上一篇'),
        $this->getNextButton('下一篇')
      ));
    }

    return '';
  }

}

分頁顯示：

{!! with(new \App\Foundations\Pagination\CustomerSimplePresenter($categories))->render() !!}

方法就是這個方法，具體修改按照自己需求重寫其中對應的顯示html元素的方法就可以了。

轉載請注明：轉載自 Ryan是菜鳥 | LNMP技術棧筆記

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