PHP error fetching json file - php

Question

Can someone help why my JSON file can't show? I beginner for JSON. This is my code, its only show blank document. I am learning this tutorial from this website http://contohprogramandroid.blogspot.com/2013/10/contoh-program-android-aplikasi-wisata.html. thank you so much.
this my image when running the code.
//this is the code webservice.php
<?php
class Database {
private $host = "localhost";
private $user = "root";
private $pass = "";
private $db = "wisata_jogja";
private $conn;
// constructor
function __construct() {
try{
$this->conn = new PDO( "mysql:host=".$this->host.";dbname=".$this->db, $this->user, $this->pass );
}catch( PDOException $e ) {
echo "error pdo $e";
}
}
public function showAllData( $table ) {
$sql ="SELECT * FROM $table";
$q = $this->conn->query( $sql ) or die( "Failed !!" );
while ( $r = $q->fetch( PDO::FETCH_ASSOC ) ) {
$data[] = $r;
}
return $data;
}
}
$database = new Database();
$response = array();
if ( isset( $_GET['get'] ) && $_GET['get']=='lokasi' ) {
$response['location'] = array();
foreach ( $database->showAllData( 'lokasi' ) as $value ) {
$kode = array();
extract( $value );
$kode['id'] = $id;
$kode['nama'] = $nama;
$kode['alamat'] = $alamat;
$kode['gambar'] = $gambar;
$kode['lat'] = $lat;
$kode['lng'] = $lng;
array_push( $response['location'], $kode );
}
echo json_encode( $response );
}
?>

Answer 1

Your condition to output is this:
if ( isset( $_GET['get'] ) && $_GET['get']=='lokasi' ) {
Thus, the script won't output any JSON since condition is not met.
From your screenshot it is clear your are missing the GET parameters.
In your browser add the parameter to the url:
http://localhost/wisata/webservice.php?get=lokasi
It's always good to take alternative action when condition is not true.
You should always echo something just so you know what is going on:
if ( isset( $_GET['get'] ) && $_GET['get']=='lokasi' ) {
//..............
echo json_encode( $response );
}else{
echo "cannot output JSON data: parameter is missing!!;
}

Answer 2

Are you sure that you pass the GET variable "lokasi" to your script ?
Otherwise, it would not go through the if condition
if(isset($_GET['get'] ) && $_GET['get']=='lokasi')
You can check this by trying to dump the variable or any foobar data inside the if condition to verify your code goes that far, for instance :
if(isset($_GET['get'] ) && $_GET['get']=='lokasi') {
$response['location'] = array();
$myTest = array('test');
var_dump($myTest); // Should display something on screen
// The rest of your code here