Java在使用相同类型时抱怨类型不兼容

Question

I tried looking around some around here and on Google, but unfortunatly found nothing.

Here is my code:

class DeleteLists
{
    public static void main(String[] args)
    {
        TokenAuth auth = new TokenAuth("xxxxx", "xxxxx");
        JKippt jkippt = new JKippt(auth);

            ClipList[] lists = jkippt.getLists();

            for (int i = 0; i <= lists.length - 1; i++)
            {
                if (lists[i].isPrivate() == false);
                {
                    {System.out.println(lists[i].getTitle);
                    jkippt.deleteList(lists[i].getId());
                }
            }
    }
}

When I try compiling it, it outputs this:

DeleteLists.java:18: error: incompatible types
        ClipList[] lists = jkippt.getLists();
                                  ^
    required: ClipList[]
    found:    Iterator<ClipList>

This could very possibly be a very basic mistake, but what am I doing wrong here?

Thank you very much in advance! Eden.

Answer 1

This method returns an Iterator :

Iterator<ClipList> it = jkippt.getLists();
while (it.hasNext()) {
  ClipList clipList = it.next();
  // do stuff with clipList
}

Deciding to return an Iterator from an API method (particularly one named getLists() ) is a strange decision, it would be better if it returned a List or a Collection (or at least a Iterable ). If that where the case, you could use it like this:

for (ClipList clipList : jkippt.getLists()) {
  // do stuff
}

Answer 2

The getLists() method returns an Iterator of ClipList elements. There are more examples in the library project page: https://code.google.com/p/jkippt/

Disclaimer: I'm the author of the library.

Answer 3

The method returns an Iterator, not an array. To go over the elements of an iterator you can use the while loop:

Iterator<ClipList> iter = jkippt.getLists();
while (iter.hasNext()) {
    ClipList list = iter.next();
    ...
}

Answer 4

You have to use an Iterator loop:

for (Iterator<ClipList> i = jkippt.getLists(); i.hasNext(); ) {
    ClipList list = i.next();
    if (!list.isPrivate()) {
        System.out.println(list.getTitle);
        i.remove();
    }
}

Note that you have a bug in your code - there is an errant semicolon after your if , which has the effect of making the if statement have an empty block.

Also, this line of yours will probably throw an ConcurrentModificationException :

jkippt.deleteList(list.getId());

so I changed it to the proper way to delete using an iterator via the remove() method.

Also note the change here to using if (!list.isPrivate()) rather than your if (list.isPrivate() == false) , which is unnecessarily cluttered.

Answer 5

As said, getLists() returns an iterator. You can convert it to an arraylist with the following code sample:

Iterator<String> lists = jkippt.getLists();
List<String> result = new ArrayList<String>();
while (list.hasNext())
  result.add(list.next());

Here result is your arraylist. If you want to convert it to an array I suggest you visit the topic ArrayList to array