Laravel 5.2按日期排序的Foreach订单

Question

我提出了一个视图，显示一篇文章以及对该文章的答复。就这个问题而言，答复是以foreach循环和随机顺序进行的。有没有办法订购foreach循环，以便最早的回复位于顶部？并在底部最古老的答复？

这个循环

@foreach($topic->replies as $reply) 
     <div class="collection"> 
      <div class="collection-item row"> 
       <div class="col s3"> 
        <div href="" class="avatar collection-link"> 
        <div class="row"> 
         <div class="col s3"><img src="/uploads/avatars/{{ $reply->user->avatar }}" alt="" class="circle" style="width: 50px;"></div> 
          <div class="col s9"> 
           <p class="user-name">{{ $reply->user->username }}</p> 
          </div> 
         </div> 
           <p>Role: {{ $reply->user->role->role_name }}</p> 
           <p>Since: {{ $reply->user->created_at }}</p> 
           <p class="post-timestamp">Posted on: {{ $reply->created_at }}</p> 
        </div> 
        </div> 
        <div class="col s9"> 
         <div class="row last-row"> 
         <div class="col s12"> 
          <p>{!! $reply->reply_text !!}</p> 
         </div> 
         </div> 
         <div class="row last-row block-timestamp"> 
         <div class="col s6"> 
          <p class="post-timestamp">Last changed: {{ $reply->updated_at }}</p> 
         </div> 
         </div> 
       </div> 
      </div> 
     </div> 
@endforeach 

TopicsController.php（显示方式）

public function show($theme_id, $topic_id) 
{ 
    $theme = Theme::with('topics')->findOrFail($theme_id); 
    $topic = Topic::with('theme')->findOrFail($topic_id); 

    return view('topics.topic')->withTopic($topic)->withTheme($theme); 

} 

提前感谢！

Answer 1

所有雄辩查询返回Laravel collections。因此，您可以使用sortBy函数在foreach中对您的答复进行排序。

@foreach($topic->replies->sortByDesc('created_at') as $reply) 

但是，更好的解决方案是在查询中排序。这可以通过更新您的口才这样的查询来实现：

$topic = Topic::with([ 
    'theme', 
    'replies' => function ($query) { 
     $query->orderByDesc('created_at'); 
    } 
]) 
->findOrFail($topic_id); 

Answer 2

public function show($theme_id, $topic_id) 
{ 
    $theme = Theme::with([ 
     'topics' => function($query) { 
      $query->orderBy('replies'); 
     } 
    ])->findOrFail($theme_id); 

    $topic = Topic::with('theme')->findOrFail($topic_id); 

    return view('topics.topic')->withTopic($topic)->withTheme($theme); 

} 

https://laravel.com/docs/5.4/eloquent-relationships#constraining-eager-loads

Answer 3

对我来说，最干净的方法是，在你的Topic模型，运用created_at时间戳，如订单默认的关系结果这个：

class Topic 
{ 
    public function replies() 
    { 
     return $this->hasMany('Reply')->orderBy('created_at','desc'); 
    } 
} 

这样你就不需要订购集合后，让sql做窝因为您几乎每次都需要以这种方式订购的主题，因此代码更轻，性能更好。

这也有你的代码共享可以保持不变的优势，但我会建议你渴望负载控制器的关系（以避免执行不必要的查询）：

$topic = Topic::with(['theme','replies'])->findOrFail($topic_id); 

希望这帮助你。