Laravel 手动分页实现

Laravel 手动分页实现

基于5.2版本

在开发过程中有这么一种情况，你请求Java api获取信息，由于信息较多，需要分页显示。Laravel官方提供了一个简单的方式paginate($perPage)，但是这种方法只适用model、查询构建器。 
今天说下 给定一个数组如何实现 和paginate方法一样的效果。

查看paginate方法源码

#vendor/laravel/framework/src/Illuminate/Database/Eloquent/Builder.php:480

public function paginate($perPage = null, $columns = ['*'], $pageName = 'page', $page = null)
{
        $query = $this->toBase();

        $total = $query->getCountForPagination();

        $this->forPage(
            $page = $page ?: Paginator::resolveCurrentPage($pageName),
            $perPage = $perPage ?: $this->model->getPerPage()
        );

        return new LengthAwarePaginator($this->get($columns), $total, $perPage, $page, [
            'path' => Paginator::resolveCurrentPath(),
            'pageName' => $pageName,
        ]);
}

从上面就可以看出，分页的关键就在于LengthAwarePaginator。

LengthAwarePaginator的构造方法。

public function __construct($items, $total, $perPage, $currentPage = null, array $options = [])
{
        foreach ($options as $key => $value) {
            $this->{$key} = $value;
        }

        $this->total = $total;
        $this->perPage = $perPage;
        $this->lastPage = (int) ceil($total / $perPage);
        $this->path = $this->path != '/' ? rtrim($this->path, '/') : $this->path;
        $this->currentPage = $this->setCurrentPage($currentPage, $this->lastPage);
        $this->items = $items instanceof Collection ? $items : Collection::make($items);
}

其实已经很明白了，假如要分页的数组为

[
    ['username'=>'zhangsan', 'age'=>26],
    ['username'=>'lisi', 'age'=>23],
    ['username'=>'wangwu', 'age'=>62],
    ['username'=>'zhaoliu', 'age'=>46],
    ['username'=>'wangmazi', 'age'=>25],
    ['username'=>'lanzi', 'age'=>24],
    ['username'=>'pangzi', 'age'=>21],
]

共7条数据，每页显示3条，共3页

use IlluminatePaginationLengthAwarePaginator;
use IlluminatePaginationPaginator;
use IlluminateHttpRequest;
# 仅做演示 #
function userList(Request $request) {
    $users = [
        ['username'=>'zhangsan', 'age'=>26],
        ['username'=>'lisi', 'age'=>23],
        ['username'=>'wangwu', 'age'=>62],
        ['username'=>'zhaoliu', 'age'=>46],
        ['username'=>'wangmazi', 'age'=>25],
        ['username'=>'lanzi', 'age'=>24],
        ['username'=>'pangzi', 'age'=>21]
    ];

    $perPage = 3;
    if ($request->has('page')) {
            $current_page = $request->input('page');
            $current_page = $current_page <= 0 ? 1 :$current_page;
    } else {
            $current_page = 1;
    }

    $item = array_slice($users, ($current_page-1)*$perPage, $perPage); //注释1
    $total = count($users);

    $paginator =new LengthAwarePaginator($item, $total, $perPage, $currentPage, [
            'path' => Paginator::resolveCurrentPath(),  //注释2
            'pageName' => 'page',
    ]);

    $userlist = $paginator->toArray()['data'];

    return view('userlist', compact('userlist', 'paginator'));
}

上面的代码中的重点是$item，如果不做注释1处理，得出的是所有7条数据。

注释2处就是设定个要分页的url地址。也可以手动通过 $paginator ->setPath(‘路径’) 设置。

页面中的分页连接也是同样的调用方式 {{ $paginator->render() }}

好了，基本就是这样，有纰漏的地方欢迎指正！

转：https://blog.csdn.net/hxx_yang/article/details/51753134