php - 从 Android Studio 的 Mysql 数据库获取数据

Question

我正在尝试从 Mysql (Wordpress) 数据库检索数据，以便在 Android 应用程序中使用它们。

我写了这个 php 程序:

    <?php

    /*
        ** Script de visualisation des données en fonction d'une certaine reqûete !
    */

    define('DB_HOST', 'localhost');
    define('DB_USER', 'user');
    define('DB_PASS', 'password');
    define('DB_NAME', 'database');

    // Connexion à la base !
    $conn = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME);

    //Checking if any error occured while connecting
     if (mysqli_connect_errno()) {
     echo "Failed to connect to MySQL: " . mysqli_connect_error();
     die();
     }

   //creating a query

    $sql = "SELECT id, title, description, coord_x, coord_y, map_id, address  FROM wpfd_5_gmp_markers";

    $products = array();

    $r = mysqli_query($conn,$sql);


    //traversing through all the result 
    while($row = mysqli_fetch_array($r)){
        array_push($products,array(
        'id'=>$row['id'],
        'title'=>$row['title'], 
        'description'=>$row['description'],
        'coord_x'=>$row['coord_x'], 
        'coord_y'=>$row['coord_y'], 
        'map_id'=>$row['map_id'],
        'address'=>$row['address']
        ));
    }

    //displaying the result in json format 
    echo json_encode(array('products'=>$products));
    echo "$products";

mysqli_close($conn);
?>

当我在导航器中启动 php 脚本时，即使我的数据库中有数据，它也只显示“数组”。

有人有想法吗？

非常感谢您的帮助。

Answer 1

Always use print_r OR var_dump to check your Array(or Array of Array...)

<?php

    $products = array();

    array_push($products, array('1', 'a', '2', 'b', '3', 'c'));

    json_encode(array('products'=>$products));

    echo "<BR>" . 'print_r: ';
    print_r ($products);

    echo "<BR>" . 'var_dump: ';
    var_dump ($products);

?>

结果:

print_r: Array ( [0] => Array ( [0] => 1 [1] => a [2] => 2 [3] => b [4] => 3 [5] => c ) ) 
var_dump: array(1) { [0]=> array(6) { [0]=> string(1) "1" [1]=> string(1) "a" [2]=> string(1) "2" [3]=> string(1) "b" [4]=> string(1) "3" [5]=> string(1) "c" } }

Result URL