Question

我正在制作一个带有摇摆的简单应用程序，当涉及到arraylists和listiterator时，我是新的。我想要做的是一个按钮，可以让你更新有关arraylist中人物的信息。我应该这样做而不使用for或for-each循环。这是我的代码：

String searchedName = JOptionPane.showInputDialog(null, "Type in the first name of the person you want to update:");
ListIterator<Student> listIt = peopleArray.listIterator();
    while(listIt.hasNext()){
        String firstname = listIt.next().getFirstname();
            if(searchedName.equalsIgnoreCase(firstname){
                String newFirstname = JOptionPane.showInputDialog(null, "Input new first name:");
                String newLastname = JOptionPane.showInputDialog(null, "Type in new last name:");
                String newEmail = JOptionPane.showInputDialog(null, "Type in new email:");
                String newOccupation = JOptionPane.showInputDialog(null, "Type in new occupation:");
                listIt.previous().setFirstname(newFirstname);
                listIt.next().setLastname(newLastname);
                listIt.previous().setEmail(newEmail);
                listIt.next().setOccupation(newOccupation);
    }
}

此代码有效，但看起来很奇怪。我是否必须跳回到第四个（listIt.next（）然后listIt.previous（））或者有更好的方法吗？

//Ñ

Answer 1

你不要急于跳起来，确保只调用next（）一次。那怎么样：

    String searchedName = JOptionPane.showInputDialog(null, "Type in the first name of the person you want to update:");
        ListIterator<Student> listIt = peopleArray.listIterator();
            while(listIt.hasNext()){
                Student studentToUpdate = listIt.next();
                    if(searchedName.equalsIgnoreCase(studentToUpdate.getFirstname()){
                        String newFirstname = JOptionPane.showInputDialog(null, "Input new first name:");
                        String newLastname = JOptionPane.showInputDialog(null, "Type in new last name:");
                        String newEmail = JOptionPane.showInputDialog(null, "Type in new email:");
                        String newOccupation = JOptionPane.showInputDialog(null, "Type in new occupation:");
                        studentToUpdate.setFirstname(newFirstname);
                        studentToUpdate.next().setLastname(newLastname);
                        studentToUpdate.setEmail(newEmail);
                        studentToUpdate.setOccupation(newOccupation);
            }
        }

Answer 2

使用旧迭代器语法的正常习语是：

Iterator<Student> studentIterator = peopleArray.iterator();
while(studentIterator.hasNext()){
  Student student = studentIterator.next();
  // Do stuff with student. For example:
  if(student.getFirstName().equalsIgnoreCase(firstname)) {
    // ...
  }
}

更新arraylist中的元素，有比这更好的方法吗？

2 个答案: