java - 添加到 ArrayList 时出现问题

Question

我看过视频、搜索过这个网站和许多其他网站，但没有什么真正有帮助的。这是我第一次使用ArrayList。如果我将 ArrayList 作为字符串，那很好，但是一旦我设置 Comment(这是类)，它就不再起作用。但导师暗示这就是它的用途。我还有另外两个类需要访问它，显然还有 main 方法。

我遇到的主要问题是它不允许我添加到数组列表中。我很困惑，这可能真的很简单。

public class Comment {

// somehow need to link it to the game/app
private ArrayList<Comment> Reply = new ArrayList<Comment>();

private String usrComment;
private String usrID;

public Comment() {
}

public Comment(String usrID, String usrComs) {
    this.usrComment = usrComs;
    this.usrID = usrID;
}

public void addReview(String addRev) {

    this.Reply.add(addRev); // not working
}

public void addReply(String addRep) {

    Reply.add(addRep); // not working and I cannot figure it out
}

public void printRep() {
    for (Comment comment : Reply) {
        System.out.println(comment);
    }
}

}

Answer 1

问题是您正在尝试添加一个String，但数组列表需要一个Comment

public void addReview(String addRev) {
    // Reply is an ArrayList<Comment> of Comments not of Strings
    // this.Reply.add(addRev); // not working
    // you can create a new Comment and then add that comment
    this.Reply.add(new Comment("userId", addRev));
}

public void addReply(String addRep) {
    // same here
    // Reply.add(addRep); // not working and I cannot figure it out
    // you can create a new Comment and then add that comment
    this.Reply.add(new Comment("userId", addRep));
}