我花了很多时间试图围绕多维数组，以构建一个PHP函数，我可以调用它来填充一个可能容纳100个元素的图库。此时，一遍又一遍地复制和粘贴HTML部分会更容易，但我想知道如何使这个工作，为未来的项目。
我已经找到了关于使用多维数字阵列的foreach循环的其他问题的解决方案，但我还没有能够使它适应我的情况。在一个例子中，最接近我自己的情况，解决方案不再有效 - 但我没有让代表对此发表评论。我使用该示例中的代码作为我自己尝试的基础。我欢迎任何帮助！我的评论可能有助于解释我想要实现的目标，如果它还不清楚的话。
到目前为止，这是我的PHP代码：
<?php
// Use PHP array to populate the image path, title (for alt tag), and longer description (for image caption)
function build_html ($imgsrc, $title, $desc) {
echo
'<div class="responsive">
<div class="gallery">
<img src="$imgsrc" alt="$title" width="300" height="200">
<div class="desc">$desc</div>
</div>
</div>';
}
// List of images; filenames will be numerical, so later I may switch to using $i++ shortcut in place of imgsrc
$gallery = array (
array (
"imgsrc" => "i/Alice0.jpg",
"title" => "Front of House",
"desc" => "View of the house from the front sidewalk"
),
array (
"imgsrc" => "i/Alice1.jpg",
"title" => "Front door",
"desc" => "Close-up of front door"
)
);
// This is just for debugging, to confirm that I really have a multidimensional array
print_r($gallery);
// BROKEN: this should use foreach loop(s) to gather the elements and pass them to the build_html function defined above.
function display_gallery () {
foreach ($gallery as $img) {
$imgsrc = $img['imgsrc'];
$title = $img['title'];
$desc = $img['desc'];
build_html($imgsrc, $title, $desc);
}
}
// Calling the function in body of page
display_gallery();
?>
编辑：我目前收到的错误消息是：
警告：为foreach（）提供的参数无效 第121行/home/varlokkur/house.anthropo.org/index.php
编辑：如果以后有人遇到这个问题，这里是我修改后的代码，按预期工作。请注意，aendeerei提供的解决方案是一个更好的示例，但此解决方案最接近原始代码。 2个更改使其工作：
固定代码：
<?php
// Use PHP array to populate the image path, title (for alt tag), and longer description (for image caption)
function build_html ($imgsrc, $title, $desc) {
echo
'
<div class="responsive">
<div class="gallery">
<img src="' . $imgsrc . '" alt="' . $title . '" width="300" height="200">
<div class="desc">'. $desc . '</div>
</div>
</div>
';
}
// List of images; filenames will be numerical, so later I may switch to using $i++ shortcut in place of imgsrc
$gallery = array (
array (
"imgsrc" => "i/Alice0.JPG",
"title" => "Front of House",
"desc" => "View of the house from the front sidewalk"
),
array (
"imgsrc" => "i/Alice1.JPG",
"title" => "Front door",
"desc" => "Close-up of front door"
)
);
// This is just for debugging, to confirm that I really have a multidimensional array
//print_r($gallery);
// BROKEN: this should use foreach loop(s) to gather the elements and pass them to the build_html function defined above.
function display_gallery ($gallery) {
// global $gallery;
foreach ($gallery as $img) {
$imgsrc = $img['imgsrc'];
$title = $img['title'];
$desc = $img['desc'];
build_html($imgsrc, $title, $desc);
// var_dump($gallery);
}
}
//var_dump($gallery);
// Calling the function in body of page
display_gallery($gallery);
?>
答案 0 :(得分：2)
Unlike in JavaScript，PHP中没有冒泡范围。 PHP中的函数作用域与外部作用域隔离。您的$gallery是在函数范围之外定义的。在函数内部，它是未定义的。这就是为什么你得到为foreach（）消息提供的无效参数的原因，因为foreach需要一个数组，但它不在那里。当您在函数中var_dump($gallery)时，您将看到它未定义。
解决方案是将$gallery传递给display_gallery()，例如
function display_gallery(array $gallery) {
// the code as is
}
display_gallery($gallery);
另一种方法是使用the global keyword：
function display_gallery() {
global $gallery;
// the code as is
}
display_gallery();
然而，虽然后者看起来像一个方便而简单的修复，reaching from an inner scope to an outer scope is usually harder to maintain and more error prone in the long run。为了完整起见，我将其包括在内，但建议使用第一种方法，例如：传入变量。
答案 1 :(得分：1)
注意：
file名称分开，因此如果它将来可能会成为整数，也可以正常使用。sprintf()中使用了函数displayImageCard()，向您展示如何实现更好的可读性以及从输出字符串中分离PHP变量。$gallery数组作为displayImageGallery()函数的参数。缺少此函数参数是您收到的错误的来源。<?php
/*
* -----------------
* Gallery functions
* -----------------
*/
/**
* Display image card.
*
* @param string $file File name.
* @param string $extension File extension (jpg|png, etc).
* @param string $path File path.
* @param string $alt Alternative text.
* @param string $title Title used in tooltips.
* @param string $description Description.
* @param integer $width Width.
* @param integer $height Height.
* @return string Output string.
*/
function displayImageCard($file, $extension, $path, $alt, $title, $description, $width = 300, $height = 200) {
echo sprintf('<div class="responsive">
<div class="gallery">
<img src="%s" alt="%s" title="%s" width="%s" height="%s">
<div class="desc">%s</div>
</div>
</div>'
, $path . $file . '.' . $extension
, $alt
, $title
, $width
, $height
, $description
);
}
/**
* Display image gallery.
*
* @param array $gallery [optional] Images list.
* @return void
*/
function displayImageGallery(array $gallery = array()) {
echo '<pre>' . print_r($gallery, true) . '</pre>';
foreach ($gallery as $key => $image) {
$file = $image['file'];
$extension = $image['extension'];
$path = $image['path'];
$alt = $image['alt'];
$title = $image['title'];
$description = $image['description'];
displayImageCard($file, $extension, $path, $alt, $title, $description);
}
}
/*
* ---------------
* Display gallery
* ---------------
*/
// Images list.
$gallery = array(
array(
'file' => 'i/Alice0',
'extension' => 'jpg',
'path' => 'abc/',
'alt' => 'Front of House',
'title' => 'Front of House',
'description' => 'View of the house from the front sidewalk',
),
array(
'file' => 'i/Alice1',
'extension' => 'jpg',
'path' => 'def/',
'alt' => 'Front door',
'title' => 'Front door',
'description' => 'Close-up of front door',
)
);
// Display image gallery.
displayImageGallery($gallery);
答案 2 :(得分：1)
这将解决它：
function display_gallery ($gallery) {
foreach ($gallery as $img) {
$imgsrc = $img['imgsrc'];
$title = $img['title'];
$desc = $img['desc'];
build_html($imgsrc, $title, $desc);
}
}
// Calling the function in body of page
display_gallery($gallery);
同样，你可以把你定义数组的部分放在函数中：
function returnArray() {
// $gallery = ...
return ($gallery);
}
然后在foreach循环中：
foreach (returnArray() as $img) { ... }