计算属性:

1. 全选状态
2. 总价
3. 总数量

src/pages/cart/cart.vue

@@ -18,8 +18,8 @@
       <radio :checked="selectAll" color="#E03440" class="select_btn" />
       <text class="select_text">全选</text>
       <text class="total_text">合计：</text>
-      <text class="price">3999</text>
+      <text class="price">{{totalPrice}}</text>
-      <view class="bottom_btn">去结算(12)</view>
+      <view class="bottom_btn">去结算({{totalCount}})</view>
     </view>
   </view>
 </template>
@@ -29,13 +29,13 @@ export default {
   data(){
     return {
       cartList: [],
-      selectAll: false
+    //   selectAll: false
     } 
   },
   onShow() {
     const cartList = uni.getStorageSync("cartList") || [];
     this.cartList = cartList
-    this.selectAll = this.cartList.every(item=>item.goods_select === true)
+    // this.selectAll = this.cartList.every(item=>item.goods_select === true)
   },
   methods: {
       // 商品选择按钮切换
@@ -46,7 +46,7 @@ export default {
         this.cartList[index].goods_select = !this.cartList[index].goods_select
 
         // 判断全选
-         this.selectAll = this.cartList.every(item=>item.goods_select === true)
+        //  this.selectAll = this.cartList.every(item=>item.goods_select === true)
       },
 
       // 商品数量的增减
@@ -74,6 +74,33 @@ export default {
               uni.setStorageSync("cartList", val)
           }
       }
+  },
+  // 计算属性
+  computed: {
+      // 全选状态
+      selectAll(){
+          return this.cartList.every(item=>item.goods_select === true)
+      },
+      // 总价格
+      totalPrice(){
+          let totalPrice = 0
+          this.cartList.forEach(item => {
+              if(item.goods_select){
+                  totalPrice += item.goods_price * item.goods_count
+              }
+          })
+          return totalPrice
+      },
+      // 总数量
+      totalCount(){
+          let totalCount = 0
+          this.cartList.forEach(item => {
+              if(item.goods_select){
+                  totalCount += item.goods_count
+              }
+          })
+          return totalCount
+      }
   }
 }
 </script>