如何使用angularjs添加购物车内物品的总金额价格

<!-- 购物按钮 -->
<button ng-click="addToCart(item)">添加到购物车</button>

<!-- 购物车视图 -->
<div>
  <h2>购物车</h2>
  <ul>
    <li ng-repeat="item in cartItems">{{ item.name }} - {{ item.price }}</li>
  </ul>
  <p>总金额：{{ calculateTotalPrice() }}</p>
</div>

// 购物车服务
app.service('CartService', function() {
  var items = [];

  this.addToCart = function(item) {
    items.push(item);
  };

  this.calculateTotalPrice = function() {
    var totalPrice = 0;
    for (var i = 0; i < items.length; i++) {
      totalPrice += items[i].price;
    }
    return totalPrice;
  };
});

// 控制器
app.controller('CartController', function($scope, CartService) {
  $scope.cartItems = CartService.items;

  $scope.addToCart = function(item) {
    CartService.addToCart(item);
  };

  $scope.calculateTotalPrice = function() {
    return CartService.calculateTotalPrice();
  };
});