第一次来这里。
我试图上传一个php格式的图片，当它为空时，值必须为null。
我试过这个代码，结果是文件字段为空！但是当我上传一些图片时，结果是双重的，一行是空值，另一行是文件字段值。我能帮忙吗？

<?php
      if (isset($_POST['save'])) {
        $target_dir = "Uploads/";
        $target_file = basename($_FILES["file"]["name"]);
        $uploadOk = 1;
        $imageFileType = pathinfo(PATHINFO_EXTENSION);
        $extensao = strtolower(substr($_FILES['file']['name'], -4));
        $novo_nome = $_POST['titulo'] . $extensao;
        $IsActive = $_POST['IsActive'];
        $titulo = $_POST['titulo'];
        $descricao = $_POST['editor'];

        if($imageFileType != "jpg" || $imageFileType != "png" || $imageFileType != "jpeg" || $imageFileType != "gif" || $imageFileType != "docx" || $imageFileType != "doc" || $imageFileType != "html" || $imageFileType != "rar" || $imageFileType != "zip" || $imageFileType != "pdf" || $imageFileType != "xls" || $imageFileType != "xlsx" || $imageFileType != "xml" || $imageFileType != "psd" || $imageFileType != "svg") {
          if(!empty($_FILES['file']))
          {
            $sqli = "INSERT INTO `noticias` (Titulo, Descricao, IsActive) VALUES ('$titulo', '$descricao', '$IsActive')";
            $result = mysqli_query($conn,$sqli);
            if ($result) {
              echo "<meta http-equiv='refresh' content='0;url=noticias.php'>";
            }
          }

          if (move_uploaded_file($_FILES["file"]["tmp_name"], $target_dir.$novo_nome)) {
            $files = basename($_FILES["file"]["name"]);
          } else {
            exit;
          }
        } else {
          echo "File Not Supported";
        }

        $location = '../bo/uploads/' . $novo_nome;
        $sqli = "INSERT INTO `noticias` (Titulo, Descricao, Imagem, IsActive) VALUES ('$titulo', '$descricao', '$location', '$IsActive')";
        $result = mysqli_query($conn,$sqli);
        if ($result) {
          echo "<meta http-equiv='refresh' content='0;url=noticias.php'>";
        }
      }
    ?>

提前谢谢！