选择JSON的一部分并检查值是否为空

Question

我有一个关于选择JSON对象的部分并检查它们是否有值的问题。
我从API加载JSON在PHP中：

$json_url ='http://api.url.com/api/gateway/call/1.4/getApp?appid=2631'; 
$ch = curl_init($json_url); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
$str = curl_exec($ch); 
curl_close($ch); 
$data = json_decode($str); 

数据的输出是：

object(stdClass)[1] 
     public 'app' => 
     array 
      0 => 
      object(stdClass)[2] 
       public 'id' => string '2631' (length=4) 
       public 'apptypeid' => string '3' (length=1) 
       public 'organizerid' => string '913' (length=3) 
       public 'accountId' => string '687' (length=3) 
       public 'name' => string 'Meet in Liege' (length=13) 
       public 'info' => string '' (length=0) 
       public 'submit_description' => string '' (length=0) 
       public 'category' => string '' (length=0) 
       public 'app_icon' => string 'upload/appimages/2631/icon1024.png' (length=34) 
       public 'homescreen' => string '' (length=0) 
       public 'token' => string 'e6615c94a8b0fed28cdbec611669b19b' (length=32) 
       public 'certificate' => string 'app2631' (length=7) 
       public 'subdomain' => string 'mil13' (length=5) 
       public 'cname' => string '' (length=0) 
       public 'advancedFilter' => string '0' (length=1) 
       public 'status' => string 'inactive' (length=8) 
       public 'isdeleted' => string '0' (length=1) 
       public 'creation' => string '2013-03-19 14:20:44' (length=19) 
       public 'defaultlanguage' => string 'fr' (length=2) 
       public 'visibleintapcrowd' => string '0' (length=1) 
       public 'applestoreid' => string '0' (length=1) 
       public 'address' => string '' (length=0) 
       public 'lat' => string '0' (length=1) 
       public 'lon' => string '0' (length=1) 
       public 'telephone' => string '' (length=0) 
       public 'email' => string '' (length=0) 
       public 'website' => string '' (length=0) 
       public 'contentmodule_css_phone' => string '' (length=0) 
       public 'contentmodule_css_tablet' => string '' (length=0) 
       public 'searchterms' => string '' (length=0) 
       public 'fbid' => string '563672167017349' (length=15) 
       public 'dropdb' => string '0000-00-00 00:00:00' (length=19) 
       public 'bundle' => string 'com.tapcrowd.meetinliege2631' (length=28) 
       public 'blankurl' => string '' (length=0) 
       public 'header_html_phones' => string '' (length=0) 
       public 'header_html_tablets' => string '' (length=0) 
       public 'footer_html_phones' => string '' (length=0) 
       public 'footer_html_tablets' => string '' (length=0) 
       public 'themeid' => string '41' (length=2) 
       public 'timestamp' => string '1368548676' (length=10) 
       public 'subflavorid' => string '12' (length=2) 
       public 'subflavortype' => string '3' (length=1) 
       public 'subflavorpaidtype' => string '9999' (length=4) 
       public 'show_external_ids_in_cms' => string '0' (length=1) 
       public 'launcherview' => string '' (length=0) 
       public 'responsive' => string '1' (length=1) 
       public 'apptype' => string 'Event Flavor' (length=12) 
       public 'channel' => string '1' (length=1) 
       public 'aboutbuttonkey' => string 'About TapCrowd' (length=14) 
       public 'aboutbuttonurl' => string 'http://m.tap.cr/about' (length=21) 
     public 'appversion' => string '' (length=0) 
     public 'events' => 
     array 
      0 => 
      object(stdClass)[3] 
       public 'id' => string '5004' (length=4) 
       ....... 

现在我想检查是否例如 '信息'， 'app_icon'，“地址'和'电子邮件'的应用程序数组是空的或不是。
有谁知道我该怎么做？这是可能的JSON查询？我想在JavaScript中做我的操作！

Answer 1

你有没有尝试过这样的：

if(empty($data->app[0]->info)){ 
    // info empty 
} 
if(empty($data->app[0]->app_icon)){ 
    // app_icon empty 
} 
if(empty($data->app[0]->address)){ 
    // address empty 
} 
if(empty($data->app[0]->email)){ 
    // email empty 
} 

如果你传递的JSON的JavaScript，然后使用（假设JSON是分配给一个变量所谓data）：

if(data.app[0].info.length === 0){ 
    // info empty 
} 

然后重复别人通过更换info与您要检查的名称。

Answer 2

你不能只是做：

if(trim($data->app[0]->info)=='' || is_null($data->app[0]->info)){ 
    echo "info empty"; 
} 

if(trim($data->app[0]->app_icon)=='' || is_null($data->app[0]->app_icon)){ 
    echo "app_icon empty"; 
} 

if(trim($data->app[0]->address)=='' || is_null($data->app[0]->address)){ 
    echo "address empty"; 
} 

if(trim($data->app[0]->email)=='' || is_null($data->app[0]->email)){ 
    echo "email empty"; 
} 

Answer 3

json_decode返回一个普通的PHP对象，所以它应该很容易。如果我没有记错的话，鉴于你$data对象的结构，这将做到这一点：

// Retrieve the app object from $data 
$app = $data->app[0]; 

// Check whatever you want with the object elements 
if empty($app->info) "info empty\n"; 
if empty($app->app_icon) "app_icon empty\n"; 
if empty($app->address) "address empty\n"; 
if empty($app->email) "email empty\n"; 

的情况下有数组中，你可能会考虑使用foreach来处理它们更app参赛对象。