创建下一个/上一个分页链接

Question

I am working on a portfolio site and have all projects in array, I have created a project template page that uses a GET variable to set the current project and load appropriate content into page. I am trying to add links at the bottom that link to the next and previous project but cannot figure out the correct way to write the link

Here is what the array looks like:

$projects = array();

$projects["Beeston-Residence"] = array(
 "name" => "Beeston House",
 "heroClass" => "hero-beeston",
 "mainImg" => BASE_URL ."images/beeston_main.jpg",
 "previewImg" => BASE_URL ."images/beeston_preview.jpg",
 "year" => "2014",
 "yearClass" => "twenty14",
 "location" => "Brisbane, Australia",
 "photographer" => "Rachel Cruz",
 "detailOne" => BASE_URL ."images/beeston_detail1.jpg",
 "detailTwo" => BASE_URL ."images/beeston_detail2.jpg",
 "detailThree" => BASE_URL ."images/beeston_detail3.jpg",
 "detailFour" => BASE_URL ."images/beeston_detail4.jpg",
 "description" => "lorem ipsum and shit",
 "detailOneSum" => "lorem ipsum detail 1",
 "detailTwoSum" => "lorem ipsum detail 2",
 "detailThreeSum" => "lorem ipsum detail 3",
 "detailFourSum" => "Lorem ipsum detail 4",
 "materials" => array("matOne","matTwo","matThree"),
 "materialImg" => array(BASE_URL ."images/beeston_mat1.jpg",BASE_URL   ."images/beeston_mat2.jpg",BASE_URL ."images/beeston_mat3.jpg"),
 "testamonialImg" => BASE_URL ."images/client.jpg",
 "testamonial" => "Cabin Is Great!"
);

$projects["Book-Tower-Residence"] = array(
 "name" => "Book Tower House",
 "heroClass" => "hero-bookTower",
 "mainImg" => BASE_URL ."images/bookTower_main.jpg",
 "previewImg" => BASE_URL ."images/bookTower_preview.jpg",
 "year" => "2012",
 "yearClass" => "twenty12",
 "location" => "London, United Kingdom",
 "photographer" => "Rachel Cruz",
 "detailOne" => BASE_URL ."images/bookTower_detail1.jpg",
 "detailTwo" => BASE_URL ."images/bookTower_detail2.jpg",
 "detailThree" => BASE_URL ."images/bookTower_detail3.jpg",
 "detailFour" => BASE_URL ."images/bookTower_detail4.jpg",
 "description" => "lorem ipsum and shit",
 "detailOneSum" => "lorem ipsum",
 "detailTwoSum" => "lorem ipsum",
 "detailThreeSum" => "lorem ipsum",
 "detailFourSum" => "Lorem ipsum",
 "materials" => array("matOne","matTwo","matThree"),
 "materialImg" => array(BASE_URL ."images/bookTower_mat1.jpg",BASE_URL ."images/bookTower_mat2.jpg",BASE_URL ."images/bookTower_mat3.jpg"),
 "testamonialImg" => BASE_URL ."images/client.jpg",
 "testamonial" => "Cabin Is Great!"
);
$projects["1917-Bungalow"] = array(
 "name" => "1917 Bungalow",
 "heroClass" => "hero-bungalow",
 "mainImg" => BASE_URL ."images/bungalow_main.jpg",
 "previewImg" => BASE_URL ."images/bungalow_preview.jpg",
 "year" => "2013",
 "yearClass" => "twenty13",
 "location" => "Autstin, Texas",
 "photographer" => "Rachel Cruz",
 "detailOne" => BASE_URL ."images/bungalow_detail1.jpg",
 "detailTwo" => BASE_URL ."images/bungalow_detail2.jpg",
 "detailThree" => BASE_URL ."images/bungalow_detail3.jpg",
 "detailFour" => BASE_URL ."images/bungalow_detail4.jpg",
 "description" => "lorem ipsum and shit",
 "detailOneSum" => "lorem ipsum",
 "detailTwoSum" => "lorem ipsum",
 "detailThreeSum" => "lorem ipsum",
 "detailFourSum" => "Lorem ipsum",
 "materials" => array("matOne","matTwo","matThree"),
 "materialImg" => array(BASE_URL ."images/bungalow_mat1.jpg",BASE_URL ."images/bungalow_mat2.jpg",BASE_URL ."images/bungalow_mat3.jpg"),
 "testamonialImg" => BASE_URL ."images/client.jpg",
 "testamonial" => "Cabin Is Great!"
);

etc... The array has 15 projects in total

The project template The projects get filtered into is set up like this:

<?php
require_once("../includes/config.php");
require_once(ROOT_PATH . "includes/projectInfo.php");
$project_id = $_GET["id"];
$project = $projects[$project_id];
include (ROOT_PATH . "includes/header-project-page.php");

?>


    <section class="l-col-group project-intro">
    <h2 class="project-title"><?php echo $project["name"]; ?> </h2>
    <aside class="project-info">
    <ul class="project-brief">
        <li class="pb-heading">STATUS </li>
        <li class="pb-info">Complete <?php echo $project["year"];?></li>
        <li class="pb-heading">LOCATION</li>
        <li class="pb-info"><?php echo $project["location"];?></li>
        <li class="pb-heading">PHOTOGRAPHER</li>
        <li class="pb-info"><?php echo $project["photographer"];?></li>
    </ul>
    </aside>
    <p class="project-summary">
        <?php echo $project["description"];?>
    </p>
</section>


<section>
    <figure class="l-col-group">

        <figcaption class= "left">
            <h3>VISION</h3>
                <p><?php echo $project["detailOneSum"];?></p>
        </figcaption>
        <img class="project-detail-img right" src="<?php echo $project["detailOne"];?>" alt="">
    </figure>


    <figure class="l-col-group">

        <figcaption class="right">
            <h3>DESIGN</h3>
                <p><?php echo $project["detailTwoSum"];?></p>
        </figcaption>
        <img  class="project-detail-img left" src="<?php echo $project["detailTwo"];?>" alt="">
    </figure>

    <figure class="l-col-group left">   

        <figcaption class="left">
            <h3>DEVELOPMENT</h3>
                <p><?php echo $project["detailThreeSum"];?></p>
        </figcaption>
        <img class="project-detail-img right" src="<?php echo $project["detailThree"];?>" alt="">
    </figure>

    <figure class="l-col-group">

        <figcaption class="right">
            <h3>TEAM</h3>
                <p><?php echo $project["detailFourSum"];?></p>
        </figcaption>
            <img class="project-detail-img left" src="<?php echo $project["detailFour"];?>" alt="">

    </figure>
</section>
<section class="testamonial">
    <img class="testamonial-image" src="<?php echo BASE_URL; ?>images/testamonial.png" alt="testamonial">
    <h3 class="testamonial-client">DAVID WALSH</h3>
    <p class="testamonial-quote">Cabin surpassed went above and beyond my wildest dreams! Customer service at its best.</p>

</section>
include (ROOT_PATH . "includes/contact.php");
include (ROOT_PATH . "includes/footer.php");
?>

I have had luck retrieving the current projects position in the array by using the following:

 <?php $key = array_search($project, $projects); 
    $offset = array_search($key, array_keys($projects));
    $next = $offset + 1;
    $prev = $offset - 1;
    ?>

But am having trouble on figuring out how to use this information to create a link to the next project in the array

I was trying something like this but do not know what to put as the link

    <?php if ($prev > 0): ?>
        <a style ="color:black" href="">Previous</a>
    <?php endif; ?>

    <?php

Thank you in advance for the help. CHEERS.

Answer 1

It's probably better and simpler to pass indexes and not ids:

// get project id
$lst_ids = array_keys($project);
$i = !empty($_GET["i"]) ? $_GET["i"] : 0;
$project_id = $lst_ids[$i];

// show previous and next links, as applicable
$l = count($projects);    // should give 15
$html = '';
if ($i) {
    $i_prev = $i - 1;
    $label = "← Previous";
    $html .= "<a href='?i=$i_prev'>$label</a>";
}

if ($i < ($l - 1)) {
    $i_next = $i + 1;
    $label = "Next&nbsp;&rarr;";
    $html .= "&nbsp;<a href='?i=$i_next'>$label</a>";
}
echo $html;

Or if you want to pass ids:

$l = count($projects);    // should give 15
$lst_ids = array_keys($project);
$project_id = !empty($_GET["id"]) ? $_GET["id"] : NULL;
$index = $project_id ? array_search($project_id, $lst_ids) : 0;

$html = '';
if ($index) {
    $id_prev = $lst_ids[$index - 1];
    $label = "← Previous";
    $html .= "<a href='?id=$id_prev'>$label</a>";
}

if ($index < ($l - 1)) {
    $id_next = $lst_ids[$index + 1];
    $label = "Next&nbsp;&rarr;";
    $html .= "&nbsp;<a href='?id=$id_next'>$label</a>";
}
echo $html;