问题描述
我正在尝试创建待办事项列表。创建新帖子时,它应该将信息编码为 json 并将信息放入 json 数组中。但不知何故,似乎信息编码不正确,并且在尝试打印帖子时,我收到错误消息“为 foreach() 提供的参数无效”。我就是找不到错误在哪里。
我对此还很陌生,所以复杂的答案可能让我难以理解。
索引:
<?PHP
spl_autoload_register(function ($class) {
include $class . '.class.PHP';
});
$allPosts = new Lista;
if(isset($_REQUEST['addNewPost'])){
$allPosts->addNewPost($_REQUEST['ett'],$_REQUEST['tva'],$_REQUEST['tre']);
}
?>
<?PHP $page_title = "Att göra lista";
include("includes/header.PHP");
?>
<?PHP
include("includes/sidebar.PHP");
?>
<h2>Min att göra lista</h2>
<form action="<?PHP echo $_SERVER['PHP_SELF'];?>" method="post">
Uppgift: <input type="text" name="ett"/><br/>
Utfarare: <input type="text" name="tva"/><br/>
Senast: <input type="text" name="tre"/><br/>
<input type="submit" name="addNewPost" value="Lägg till post"/>
</form>
<?PHP
//Loopa igenom array
foreach ($allPosts->getTheList() as $key=>$val) {
echo "<section id='postPart'>" . $val->getEtt() . "<br/>" . $val->getTva(). " " . $val->getTre(). "</section><section id='buttonPart'><button type='button' name='klar'>Avklarad!</button> <button type='button' name='deletePost'>Ta bort</button>\n";
}
//echo "<section id='postPart'>" . $_REQUEST['one'] . "<br/>" . $_REQUEST['two'] . " " . $_REQUEST['three'] . "</section><section id='buttonPart'><button type='button' name='klar'>Avklarad!</button> <button type='button' name='deletePost'>Ta bort</button>\n";
var_dump($allPosts);
?>
</body>
</html>
班级:利斯塔:
<?PHP
class Lista{
public $theList=[];
function __construct(){
if(file_exists("text.json")>0)
$this->theList = json_decode(file_get_contents('text.json'),true);
}
function addNewPost($ett,$tva,$tre){
$posten = new Post ($ett,$tre);
array_push ($this->theList,$posten);
$jsonStr = json_encode($this->theList);
file_put_contents("text.json",$jsonStr);
}
function getTheList( ){
return $this->theList;
}
}
班级帖子:
<?PHP
class Post{
public $ett;
public $tva;
public $tre;
function __construct ($ett,$tre){
$this->ett = $ett;
$this->tva = $tva;
$this->tre = $tre;
}
function getEtt():string{
return $this->ett;
}
function getTva(){
return $this->tva;
}
function getTre(){
return $this->tre;
}
}
解决方法
我认为您的问题出在这一行:
$jsonStr = json_encode($this->$thePost,JSON_PRETTY_PRINT);
您可能正在尝试这样做:
$jsonStr = json_encode($thePost,JSON_PRETTY_PRINT);
因为 $thePost 是一个对象,而不是您的类的属性。如果 $thePost 是一个匹配属性名称的字符串,它就可以工作。
,除了打字错误之外,要对对象数组进行 json_encode,您需要创建一个导出器方法,该方法返回每个属性的数组或实现 JsonSerializable
<?php
class Post implements JsonSerializable {
protected $whatIs = ' ';
protected $whoIs = ' ';
protected $whenIs = ' ';
function __construct($what,$who,$when){
$this->whatIs=$what;
$this->whoIs=$who;
$this->whenIs=$when;
}
public function jsonSerialize()
{
return get_object_vars($this);
}
}
$arr = [];
$arr[] = new Post(1,2,3);
echo json_encode($arr);
结果:
[{"whatIs":1,"whoIs":2,"whenIs":3}]