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首页 > 解决方案 > php - 警告：无法修改标头信息 - 标头已由（输出开始于 C:\xampp\htdocs\x\includes\nav-top.php:46）

php - php - 警告：无法修改标头信息 - 标头已由（输出开始于 C:\xampp\htdocs\x\includes\nav-top.php:46）

问题描述

我昨天遇到了这个问题，我仍在努力解决。在大家对此投反对票之前，我想说是的，我已经提到了其他类似的问题，但我无法解决我的问题。所以，这是我的问题。我有一个nav-top.php基本上包含项目导航栏的文件。代码是

<?php
include('../includes/config.php');
$result1=mysqli_query($db,"SELECT * FROM `category`;");?>
<!doctype html>
<html lang="en">
  <head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="../css/bootstrap.min.css">
    <script src="../js/jquery.min.js"></script>
       <!--font awesome
       <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.2.0/css/solid.css" integrity="sha384-wnAC7ln+XN0UKdcPvJvtqIH3jOjs9pnKnq9qX68ImXvOGz2JuFoEiCjT8jyZQX2z" crossorigin="anonymous">
        <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.2.0/css/fontawesome.css" integrity="sha384-HbmWTHay9psM8qyzEKPc8odH4DsOuzdejtnr+OFtDmOcIVnhgReQ4GZBH7uwcjf6" crossorigin="anonymous">-->
    <link rel="stylesheet" href="../css/fawesome/css/all.css">
    <title>Fast-Fries</title>
  </head>
  <style>

      .bg-black{
        background-color: #242323;
      }

  </style>
  <body>
<nav class="navbar navbar-expand-lg navbar-dark bg-black">
    <div class="container">
       <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarTogglerDemo01" aria-controls="navbarTogglerDemo01" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
       </button>
          <div class="collapse navbar-collapse" id="navbarTogglerDemo01">
                <ul class="nav navbar-nav pull-sm-left">
                      <ul class="navbar-nav mr-right mt-2 mt-lg-0">
                          <li class="nav-item dropdown bg-primary">
                            <a class="nav-link dropdown-toggle bg-black" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Our Menu</a>
                            <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                              <a class="dropdown-item" href="../src/menu.php">View All</a>
                                <div class="dropdown-divider"></div>
                             <?php if($result1->num_rows>0){
                                 while($row=$result1->fetch_assoc()){?>
                              <a class="dropdown-item" href="../src/menu.php?type=<?php echo $row['cat_id']; ?>"><?php echo $row['cat_title']; ?></a>
                                <div class="dropdown-divider"></div>
                                 <?php }} ?>
                            </div>
                          </li>
                    </ul>
                  <li class="nav-item">
                    <a class="nav-link" href="#">Special Combos</a>
                  </li>
                </ul>
                <ul class="nav navbar-nav navbar-logo mx-auto">
                  <li class="nav-item">
                    <a class="nav-link" href="../src/home.php"><img src="../images/logo.png" style="width:25px;"></a>
                  </li>
                </ul>
                <ul class="nav navbar-nav pull-sm-right">
                      <ul class="navbar-nav mr-right mt-2 mt-lg-0">
                          <li class="nav-item dropdown bg-primary">
                            <a class="nav-link dropdown-toggle bg-black" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">User</a>
                            <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                              <a class="dropdown-item" href="../src/all-products.php?id=<?php echo $row['cat_id']; ?>">Breakfast</a>
                                <div class="dropdown-divider"></div>
                              <a class="dropdown-item" href="../src/all-products.php?id=<?php echo $row['cat_id']; ?>">Lunch</a>
                                <div class="dropdown-divider"></div>
                              <a class="dropdown-item" href="../src/logout.php">Logout</a>
                            </div>
                          </li>
                    </ul>
                </ul>
          </div>
    </div>
</nav>

当在页面上按下添加到购物车按钮时，我正在尝试刷新我的food-detail.php页面。的代码food-detail.php是：

<?php
session_start();
if(!isset($_SESSION['id'])){
    header('Location:index.php');
}
include('../includes/nav-top.php');
if(isset($_GET['id'])){
    $id = $_GET['id'];
    $result=mysqli_query($db,"SELECT * FROM `food`, `category` WHERE food.category=category.cat_id AND food.id=$id"); //The query was changed from select * from food to this query in order to extract cat_title
    if($result->num_rows>0){
        if($row=$result->fetch_assoc()){?>
               <div class="container">
                <div class="row">
                    <div class="col-lg-6 col-sm-6"  style="margin-top:70px;">
                        <img src="../images/food/<?php echo $row['food_img']; ?>">
                    </div>
                    <div class="col-lg-6 col-sm-6"  style="margin-top:70px;">
                        <label><h1><?php echo $row['food_name']; ?></h1></label><br>
                        <label><b>Category: </b><label><?php echo $row['cat_title']; ?> <a href="menu.php?type=<?php echo $row['cat_id']; ?>">(View More)</a></label></label><br>
                        <label><b>Veg/Non Veg: </b><?php
                            if(($row['veg_nonveg'])=='veg'){
                                echo '<label style="color:green">'.$row['veg_nonveg'].'</label>';
                            }
                             else{
                                echo '<label style="color:red">'.$row['veg_nonveg'].'</label>';

                                }
                            ?></label><br>
                        <label><b>Price: </b>Rs.<?php echo $row['price']; ?> Per Burger</label><br>
                        <label><b>Quantity Left: </b><?php 
                                        if($row['quantity'] <= 5 ){ echo '<label style="color:red">'.$row['quantity']."</label>";
                                        }
                                        else{
                                            echo '<label style="color:green">'.$row['quantity']."</label>";
                                        }
                            ?></label><br>
                            <form action="" method="POST">
                                <label><b>Enter Quantity: </b></label><input type="number" class="form-inline" name="quantity" value="1" min="1" max="<?php echo $row['quantity'];?>" style="text-align:center;">
                                <input type="submit" class="btn btn-outline-success btn-lg" style="margin-top:25px; margin-bottom: 30px;" value="Add To Cart" name="cart">
                            </form>
                    </div>
                </div>
            </div>

<?php        }
        }
    //code for when add to cart is pressed
if(isset($_POST['cart'])){
    $userid = $_SESSION['id'];
    $qty = $_POST['quantity'];
    $result2=mysqli_query($db,"INSERT INTO `cart`(`food_id`, `food_quantity`, `user_id`) VALUES ($id,$qty,$userid)");
    $result3=mysqli_query($db,"UPDATE `food` SET `quantity`= `quantity` - $qty WHERE `id`=$id");
    header('Location: food-detail.php');
        }
  } // end of outer if
else{
    echo '<br><div class="container"><h1 style="color:red"> Uh-oh. It seems you are trying<br>to view the wrong food.</h1>';
    echo '<a href="home.php">Click Here To Go Back To Home Page.</a></div>';
}
include('../includes/footer-bottom.php')?>

我收到警告：无法修改标头信息 - 标头已由（输出开始于 C:\xampp\htdocs\x\includes\nav-top.php:46）错误发送。请帮忙。谢谢你。

标签： phpmysql

解决方案

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