从Java中删除ArrayList中的对象出错[Eclipse]

Question

我有这个方法从ArrayList 中删除特定的对象P.

这是我的代码:

public void removeProduct(Product p) throws StockException{
        int flag=0;
        for(Product i:StockProducts)
            if(p.getCode()==i.getCode()){
                this.StockProducts.remove(p);
                flag=1;
            }

        if(flag==0){
                StockException e = new StockException("could not remove the Product , PRODUCT IS NOT IN THE STOCK:  ", p);
        throw e;
          }
    }

错误:

Exception in thread "main" java.util.ConcurrentModificationException
    at java.util.ArrayList$Itr.checkForComodification(Unknown Source)
    at java.util.ArrayList$Itr.next(Unknown Source)
    at Stock.removeProduct(Stock.java:29)
    at Test.main(Test.java:18)

如果您需要有关我的代码的更多信息,请告诉我

添加方法

public void addProduct(Product p) throws StockException{
        for(Product i:StockProducts)
            if(p.getCode()==i.getCode()){
                        StockException e = new StockException("could not add the Product , CODE ALREADY EXIST IN STOCK: ", p);
                throw e;
                    }

                    this.StockProducts.add(p);  
    }

Answer 1

您正在ArrayList尝试迭代它时从中删除对象.正如其他人向你指出的那样,这不起作用并且正在给你ConcurrentModificationException.你想要这样的东西:

if(StockProducts.contains(p))
   StockProducts.remove(p);

或者,如果您真的想要遍历列表并进行更改,那么您应该可以使用ListIterator如下所示:

ListIterator<Product> iter = StockProducts.listIterator();
while(iter.hasNext()){
    if(iter.next().equals(p)){
        iter.remove(p);
    }
}

或者如果列表可以有多个Product具有相同结果的s getCode():

ListIterator<Product> iter = StockProducts.listIterator();
while(iter.hasNext()){
    if(iter.next().getCode() == p.getCode()){
        iter.remove(p);
    }
}