我正在生成菜肴列表(对象),当用户点击按钮时,InitializeFoodList()应该将所选项目添加到sessionStorage。然后在RetrieveDataFromCart()中,我想遍历sessionStorage并在控制台中显示所有这些项目。
问题是最终结果是item属性为null或者它只是显示最后添加的项目而下一个是null。
任何人都知道更好的方法来实现这一目标吗?
var list = [{
id: 1,
name: "Spaghetti",
price: 15,
category: "main",
pictureSrc: "images/food/spaghetti.jpg"
},
{
id: 2,
name: "Lasagne",
price: 20,
category: "main",
pictureSrc: "images/food/Lasagne.jpg"
},
{
id: 3,
name: "Coca-cola",
price: 5,
category: "drinks",
pictureSrc: "images/food/cola.jpg"
},
{
id: 4,
name: "Chicken",
price: 12,
category: "main",
pictureSrc: "images/food/chicken.jpg"
},
];
function InitializeFoodList() {
var foodList = $('#foodList');
for (let i = 0; i < list.length; i++) {
const element = list[i];
var buttonText = '<button class="btn btn-primary add" id="add' + i + '">+</button><button class="btn btn-primary" name="remove">-</button>';
foodList.append("<li class='list-inline-item'><h4>" + element.name + "</h4><p>" + element.price + " zł</p><img alt=''height='200' width='200' class='img-thumbnail' src='" + element.pictureSrc + "'><br>" + buttonText + "</li>");
$('#add' + i).click(function() {
sessionStorage.setItem("cart", JSON.stringify(element));
});
}
}
function RetrieveDataFromCart() {
var elements = [];
for (let i = 0; i < sessionStorage.length; i++) {
var element = JSON.parse(sessionStorage.getItem(localStorage.key(i)));
elements.push(element);
console.log(element.name);
}
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>
<button onclick="InitializeFoodList()">Click me</button>
<button onclick="RetrieveDataFromCart()">Retrieve</button>
<ul id="foodList" class="list-inline"></ul>
</div>
答案 0 :(得分:1)
我只是将整个数组保存在一个键下
然后,您可以在内存中添加/删除或修改数组中的对象,并在每次更改时存储已修改的数组
function getStoredCart(){
// return stored array and if not existing return an empty array
return JSON.parse(sessionStorage.getItem('cart') || '[]')
}
function saveCart(array){
sessionStorage.setItem("cart", JSON.stringify(array));
}
// example deleting item
function deleteItem(item){
var itemIndex = cartList.indexOf(item)
cartArray.splice(itemIndex,1); // remove from stored array
saveCart(cartArray ); // save it back into storage
}
// example adding item
function addItem(itemObject){
cartArray .push(itemObject); // push new object to array
saveCart(cartArray ); // save it back into storage
}
// keep array reference in variable whole time page is active
var cartArray = getStoredCart();
$.each(cartArray , function(i, item){
// add the html for each item and use `item` reference in click handlers when doing modifications
})
答案 1 :(得分:0)
您正在使用sessionStorage,但此代码段中存在一些问题。首先,在sessionStorage中设置项目时,每次都会添加“cart”作为键,因此它会覆盖存储的先前值,因为sessionStorage中的项目存储为键值对,键应该是唯一的,否则它会更新存储在同样的关键。
所以我增加了i的值,键名为'cart',即'cart'+ i。您可以根据用例使用任何唯一键。 其次,而不是使用localStorage使用会话存储获取特定密钥(似乎是一些错字)
更新了代码段
var list = [{
id: 1,
name: "Spaghetti",
price: 15,
category: "main",
pictureSrc: "images/food/spaghetti.jpg"
},
{
id: 2,
name: "Lasagne",
price: 20,
category: "main",
pictureSrc: "images/food/Lasagne.jpg"
},
{
id: 3,
name: "Coca-cola",
price: 5,
category: "drinks",
pictureSrc: "images/food/cola.jpg"
},
{
id: 4,
name: "Chicken",
price: 12,
category: "main",
pictureSrc: "images/food/chicken.jpg"
},
];
function InitializeFoodList() {
var foodList = $('#foodList');
for (let i = 0; i < list.length; i++) {
const element = list[i];
var buttonText = '<button class="btn btn-primary add" id="add' + i + '">+</button><button class="btn btn-primary" name="remove">-</button>';
foodList.append("<li class='list-inline-item'><h4>" + element.name + "</h4><p>" + element.price + " zł</p><img alt=''height='200' width='200' class='img-thumbnail' src='" + element.pictureSrc + "'><br>" + buttonText + "</li>");
$('#add' + i).click(function() {
sessionStorage.setItem("cart" + i, JSON.stringify(element));
});
}
}
function RetrieveDataFromCart() {
var elements = [];
for (let i = 0; i < sessionStorage.length; i++) {
var element = JSON.parse(sessionStorage.getItem(sessionStorage.key(i)));
elements.push(element);
console.log(element.name);
}
}