Php Can'；t使用JSON解码处理foreach级别

我已经处理这个问题大约5个小时了，所以我想是时候在这里提问了

我使用FacebookGraphAPI检索数据，并使用JSON解码将其全部放在PHP上

以下是FB图：

{
  "feed": {
    "data": [
      {
        "message": "A file.",
        "id": "831407506978898_831408573645458",
        "attachments": {
          "data": [
            {
              "target": {
                "id": "1041214692589250",
                "url": "https://www.facebook.com/download/A-PDF-FILE.pdf"
              },
              "title": "Clase 01 - Vías de administración.pdf",
              "type": "file_upload",
              "url": "https://www.facebook.com/download/A-PDF-FILE.pdf"
            }
          ]
        }
      },
      {
        "picture": "https://fbcdn-photos-c-a.akamaihd.net/A-PHOTO.jpg",
        "message": "A photo.",
        "id": "831407506978898_831408496978799",
        "attachments": {
          "data": [
            {
              "description": "A photo.",
              "media": {
                "image": {
                  "height": 540,
                  "src": "https://fbcdn-photos-c-a.akamaihd.net/A-PHOTO.jpg",
                  "width": 720
                }
              },
              "target": {
                "id": "10207838160017396",
                "url": "https://fbcdn-photos-c-a.akamaihd.net/A-PHOTO.jpg"
              },
              "type": "photo",
              "url": "https://fbcdn-photos-c-a.akamaihd.net/A-PHOTO.jpg"
            }
          ]
        }
      },
      {
        "picture": "https://fbcdn-photos-c-a.akamaihd.net/A-PHOTO.jpg",
        "id": "831407506978898_831408450312137",
        "attachments": {
          "data": [
            {
              "media": {
                "image": {
                  "height": 540,
                  "src": "https://fbcdn-photos-c-a.akamaihd.net/A-PHOTO.jpg",
                  "width": 720
                }
              },
              "target": {
                "id": "10207838168217601",
                "url": "https://fbcdn-photos-c-a.akamaihd.net/A-PHOTO.jpg"
              },
              "type": "photo",
              "url": "https://fbcdn-photos-c-a.akamaihd.net/A-PHOTO.jpg"
            }
          ]
        }
      },
      {
        "message": "TEST",
        "id": "831407506978898_831407576978891"
      },
      {
        "id": "831407506978898_831407516978897"
      }
    ],
    "paging": {
      "previous": "https://graph.facebook.com/...alotofjunk"
    }
  },
  "id": "0000000000000"
}

我的PHP如下所示：

<?php

header('Content-Type: text/html; charset=utf-8');
$limit = 60; // The number of posts fetched
$access_token='TOKEN NUMBER';
$group_id = 'GROUPNUMBER';
$url1 = 'https://graph.facebook.com/'.$group_id.'?access_token='.$access_token;
$des = json_decode(file_get_contents($url1)) ;
$url2 = "https://graph.facebook.com/{$group_id}/feed?access_token={$access_token}";
$data = json_decode(file_get_contents($url2));
?>

 <?
$counter = 0;
foreach($data->data as $d) {
if($counter==$limit)
break;
?>

<? $themessage = (isset($d->message) ? $d->message : false); ?>
<? print $themessage ?>

<? $thepicture = (isset($d->picture) ? $d->picture : false); ?>
<? print "<img src=\"$thepicture\">" ?>

<!--THE PROBLEM IS FROM HERE.... -->
    <?
    $counter = 0;
    foreach($d->attachments->data as $d2) {
    if($counter==$limit)
    break;
    ?>

<? $attachments = (isset($d2->url) ? $d2->url  : false); ?>
<? print $attachments ?>

    <?
    }
    ?>
<!-- ...TO HERE -->    

<?
$counter++;
}
?>

我获得了$themessage和$thepicture的完美输出，但如果使用$attachments，我会收到以下错误：

• 注意：未定义的属性：stdClass:：$attachments in
• 注意：正在尝试获取
• 警告：为中的foreach（）提供的参数无效

我已经读过了，但是运气不好

---

我怎样才能解决这个问题？。非常感谢

链接对象时需要小心，尤其是在循环中。一个空的物体会把整个表演打倒。试试这个：

$counter = 0;
if( isset( $d->attachments ) )
{
    foreach( $d->attachments->data as $d2 )
    {
        ....
    }
}

出现此错误是因为在第一个循环中缺少提要对象 这里

更换

foreach($data->data as $d) {
if($counter==$limit)
break;
?>

与

 foreach($data->feed->data as $d) {
    if($counter==$limit)
    break;
    ?>

您的JSON是这种格式的。请将您的JSON粘贴到此处并进行检查

我试过你的代码我可以在这里打印url

$data=“您的JSON在此”
foreach（$data->feed->data as$d）{
$themessage=（设置为（$d->message）？$d->message:false）；
打印（“\n”。$themessage）；
$thepicture=（设置为（$d->picture）？$d->picture:false）；
打印（“\n”）；
foreach（$d->附件->数据为$d2）{
$attachments=（isset（$d2->url）？$d2->url:false）；
打印（“\n”。$附件）；
}
}

旁注：您正在初始化$counter=0；两次一次内循环

---

在循环之外，即使是$attachment也是不好的，这是我在第一次查看代码后的看法，无论您是出于什么原因，它都可以运行良好！。谢谢兄弟！

 foreach($data->feed->data as $d) {
    if($counter==$limit)
    break;
    ?>

$data="Your JSON Here"
foreach($data->feed->data as $d) {
   $themessage = (isset($d->message) ? $d->message : false);
   print("\n".$themessage);
   $thepicture = (isset($d->picture) ? $d->picture : false);
   print("\n<img src='$thepicture'>");
   foreach($d->attachments->data as $d2) {
     $attachments = (isset($d2->url) ? $d2->url  : false);  
     print("\n".$attachments);
   }
}