PHP - 尝试显示xml标记（具有相同名称的标记）nodevalue

Question

I am trying to display information from a XML file. I am using PHP and its DOMDocument class. I am attaching the xml file and the php code that i have tried.

<?xml version="1.0" encoding="utf-8" ?>
<services>
<service>
    <type>Wash</type>
    <title>Wash1</title>
    <content>Full Exterior Hand Wash</content>
    <content>Chamois dry, Pressure Clean Wheels, All Door Jambs</content>   
    <content>Plus Free Typre Gloss</content>
    <price>Hatch/Sedan:$15</price>
    <price>Others:$20</price>
</service>

<service>
    <type>Wash</type>
    <title>Wash2</title>
    <content>Wash1</content>
    <content>Plus Vacuum</content>   
    <content>Glass Cleaned(IN/OUT)</content>
    <content>Plus Free Interior Wipe</content>
    <price>Hatch/Sedan:$30</price>
    <price>Others:$38</price>
 </service>
 </services>

The php code...

    <?php
    header('Content-Type: text/html;charset=utf8');

    $xmlfile = new DOMDocument();
    $xmlfile->load('services.xml');

    $services = $xmlfile->getElementsByTagName('service');

    foreach($services as $service){
         $titles = $service->getElementsByTagName('title');
         $title = $titles->item(0)->nodeValue;
         echo "<h1>$title</h1>";

         $prices = $xmlfile->getElementsByTagName('price');

         foreach($prices as $price){
             $price = $prices->item(0)->nodeValue;
             echo "<h1>$price</h1>";
         }

     }
?>

I am only trying to output price tag values, since if that works displaying content shouldn't be a problem. Eventually i will be displaying these values in HTML structure, one by one.

Thanks for your help.

Edit: This code at the moment outputs

Wash1
Hatch/Sedan:$15
Hatch/Sedan:$15
Hatch/Sedan:$15
Hatch/Sedan:$15
Wash2
Hatch/Sedan:$15 
Hatch/Sedan:$15
Hatch/Sedan:$15
Hatch/Sedan:$15

Answer 1

You've got two bugs here. As pointed out in another answer, you're getting $prices from the wrong element:

$prices = $xmlfile->getElementsByTagName('price');

... should be:

$prices = $service->getElementsByTagName('price');

This doesn't fix the problem completely, however, as there's another problem. You're looping through the prices but then always returning the first <price>. You need to change this:

$price = $prices->item(0)->nodeValue;

... to this:

$price = $price->nodeValue;

---

The corrected code then becomes:

<?php
header('Content-Type: text/html;charset=utf8');

$xmlfile = new DOMDocument();
$xmlfile->load('services.xml');

$services = $xmlfile->getElementsByTagName('service');

foreach($services as $service){
     $titles = $service->getElementsByTagName('title');
     $title = $titles->item(0)->nodeValue;
     echo "<h1>$title</h1>";

    $prices = $service->getElementsByTagName('price');

    foreach($prices as $price){
        $price = $price->nodeValue;
        echo "<h1>$price</h1>";
    }

}

... which outputs:

Wash1

Hatch/Sedan:$15

Others:$20

Wash2

Hatch/Sedan:$30

Others:$38

---

You've asked when it's necessary to use item(). This basically depends on whether you're dealing with a set of nodes (a DOMNodeList) or a single node (DOMNode). getElementsByTagName returns a DOMNodeList (there might be lots of elements) so you need to select a single one, e.g.:

 $titles = $service->getElementsByTagName('title'); // Returns a `DOMNodeList` with all the titles
 $title = $titles->item(0)->nodeValue;              // Grabs just the first title

You can iterate through a DOMNodeList (it implements the Traversable) interface. When you iterate you get a DOMNode back:

$prices = $service->getElementsByTagName('price'); // Returns a `DOMNodeList`
foreach ($prices as $price) { // $price is a `DOMNode`
    // ...
}