salesforce 零基础学习（六十三）Comparable实现Object列表数据的自定义排序

Posted 2020-08-27 zero.zhang

项目中通常有些需求为需要将某个sObject的数据列表按照某种规则排序显示到前台页面上，但是list上面的sort远远满足不了复杂的功能，此种情况需要自定义比较两个object大小的方法，所以需要创建Compare相关的类实现Comparable接口。

 需求：实现Goods__c列表排序，GoodsBrand__c为华为的按照价格升序排序，GoodsBrand__c为联想的按照价格降序排列。

 1 public without sharing class ComparedGoods implements Comparable{
 2     private Goods__c goods{get;set;}
 3     
 4     private static final String GOODS_BRAND_HUAWEI = \'华为\';
 5     
 6     private static final String GOODS_BRAND_LIANXIANG = \'联想\';
 7     
 8     public ComparedGoods(Goods__c obj) {
 9         goods = obj;
10     }
11     
12     public Integer compareTo(Object objectToCompareTo) {
13             Goods__c comparedGoods = (Goods__c)objectToCompareTo;
14             Integer comparedResult = 0;
15             if(comparedGoods.GoodsBrand__c == GOODS_BRAND_HUAWEI) {
16                 if(goods.GoodsPrice__c > comparedGoods.GoodsPrice__c) {
17                     comparedResult = 1;
18                 } else if(goods.GoodsPrice__c < comparedGoods.GoodsPrice__c) {
19                     comparedResult = -1;
20                 }
21             } else if(comparedGoods.GoodsBrand__c == GOODS_BRAND_LIANXIANG) {
22                 if(goods.GoodsPrice__c > comparedGoods.GoodsPrice__c) {
23                     comparedResult = -1;
24                 } else if(goods.GoodsPrice__c == comparedGoods.GoodsPrice__c) {
25                     comparedResult = 0;
26                 } 
27                 else if(goods.GoodsPrice__c < comparedGoods.GoodsPrice__c) {
28                     comparedResult = 1;
29                 }
30             }
31             return comparedResult;
32     }
33 }

用法：

总结：针对object需要比较大小的时候，可以实现Comparable接口，在其compareTo方法中实现比较的逻辑即可。此篇有错误的地方欢迎指正，有问题欢迎留言。