问题描述
我有一个名为 removeSup 的方法，它应该从补充列表中删除一个对象 Supplement 。
这是方法的代码：
I've got a method called removeSup which is supposed to remove an object Supplement from a list of supplements.this is the code for the method:
private static void removeSup(Supplement supToRemove, List<Supplement> listToRemoveFrom) {
Iterator<Supplement> iterator = listToRemoveFrom.iterator();
while(iterator.hasNext()){
if(iterator.next().equals(supToRemove)){
iterator.remove();
}
}
}
有一个叫做 magazine ，它定义了补充列表。
there is a class called magazine which defines the list of supplements.
public class Magazine {
private List<Supplement> supList;
public List<Supplement> getSupList() {
return this.supList;
}
public void setSupList(List<Supplement> supList) {
this.supList = supList;
}
public Magazine(Double cost, String _name){
this.supList = new ArrayList<>();
this.weekCost = cost;
this.name = _name;
}
}
班级补充具有以下构造函数
public Supplement(String _name, Double _price, String _magName ){
this.name=_name;
this.price=_price;
this.magName = _magName;
}
c>搜索用户可以删除某个补充
in the main class client there is a search that the user can do to remove a certain Supplement
private static void searchSup(){
System.out.println("Search for Supplement");
String search = scanner.nextLine();
for (Supplement sup : magazine.getSupList()) {
if (!sup.getSupName().equalsIgnoreCase(search)) {
//do something
}
else{
removeSup(sup,magazine.getSupList());
}
}
}
客户端的主要方法课程如下：
}the main method in the client class is as follows:
private Magazine magazine;
public static void main(String[] args) {
magazine = new Magazine(3.0, "pop");
List<Supplement> startList = new ArrayList<>();
startList.add(new Supplement("Nat Geo", 3.0,"pop"));
startList.add(new Supplement("Discovery", 5.0,"pop"));
startList.add(new Supplement("Health", 6.3,"pop"));
startList.add(new Supplement("IT", 8.3,"pop"));
magazine.setSupList(startList);
searchSup();
}
当我运行此程序并输入任何添加的补充剂时，我得到一个错误
When I run this program and type any of the added supplements, i get an error
Exception in thread "main" java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:859)
at java.util.ArrayList$Itr.next(ArrayList.java:831)
at Client.searchSup(Client.java:131)
at Client.searchSup(Client.java:140)
at Client.main(Client.java:588)
是我用来搜索的for循环给我一个错误？如果是这样我将如何解决此问题？
is it the for loop i am using to search giving me an error? if so how would i go about fixing this?
推荐答案
我发现我正在进行的搜索不适用于我我想这样做我创建了一个方法，它返回列表中Supplement的整数。
I figured out that the search i was doing was not working with what i wanted to do so i created a method which returns an integer of the Supplement in the list.
private static int indexOfSup(List<Supplement> supSearchList, String nameOfSup) {
for (Supplement sup : supSearchList) {
if (sup.getSupName().equalsIgnoreCase(nameOfSup)) {
return supSearchList.indexOf(sup);
}
}
return -1;
}
然后使用此整数从列表中删除。
a简单 List.Remove（index）工作正常
i then use this integer to remove from the list.a simple List.Remove(index) worked fine
感谢所有回复。
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