Php 谷歌FCM字段“；“数据”；必须是JSON数组

我正在尝试在Android设备上发送Google FireBase推送通知。遵循我的代码

function send_android_notification($deviceToken="",$message="",$input_data=array())
  {       
    $apiKey =  'XXXXXXXXXX';
    // Set POST variables
    $url = 'https://fcm.googleapis.com/fcm/send';
    $fields = array(
            //'to'  => $deviceToken,
            'registration_ids' => array($deviceToken),
            'notification'=> array( "body" => $message,"title"=>"ABCD","icon"=>""),
            'data' => $input_data
            );
    $headers = array( 
              'Authorization: key=' . $apiKey,
              'Content-Type: application/json'
            );
    // Open connection
    $ch = curl_init($url);
    // Set the url, number of POST vars, POST data
    //curl_setopt( $ch, CURLOPT_URL, $url );
    curl_setopt($ch, CURLOPT_HEADER, false);
    curl_setopt( $ch, CURLOPT_POST, true );
    curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
    curl_setopt( $ch, CURLOPT_POSTFIELDS, json_encode( $fields ) );
    // Execute post
    $result1 = curl_exec($ch);
    echo $result1;
    curl_close($ch);
  }

但当我发送推送通知时，它会给我以下错误

---

字段“数据”必须是JSON数组：[]

您需要将数组编码为JSON

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json\u encode（$input\u data）

您需要将数组编码为json

---

json\u encode（$input\u data）

试试这个json\u encode（$fields，json\u FORCE\u OBJECT）谢谢@Scaffold你节省了我的时间。完美无缺地尝试这个json_编码（$fields，json_FORCE_OBJECT）谢谢@Scaffold你节省了我的时间。完美无缺