java - 我如何从好友图像更改 Xmpp android 获得通知

Question

我正在尝试开发一个 Xmpp 客户端并显示带有图像的好友列表。我将图像存储在缓存目录中以便快速检索和不必要的网络使用。这里的问题是如果好友更改了他的图像，我如何得到通知以获取新图像来自服务器，而不是来自本地缓存。请建议。

我正在使用 asmack api。

Answer 1

private static XMPPConnection connection;

// If any changes occured in buddylist
connection.getRoster().addRosterListener(new RosterListener() {

            @Override
            public void presenceChanged(Presence arg0) {

            }

            @Override
            public void entriesUpdated(Collection<String> arg0) {

            }

            @Override
            public void entriesDeleted(Collection<String> arg0) {

            }

            @Override
            public void entriesAdded(Collection<String> arg0) {

            }
        });

获取用户列表

private ArrayList<HashMap<String, String>> getUserList() throws Exception {

        ArrayList<HashMap<String, String>> userList = new ArrayList<HashMap<String, String>>();
        if (isConnectionAlive() || reConnectAndAuth()) {
            Roster roster = connection.getRoster();
            Collection<RosterEntry> entries = roster.getEntries();
            for (RosterEntry entry : entries) {
                String avatarPath = "";
                VCard vCard = new VCard();
                try {
                    vCard.load(connection, entry.getUser());
                    vCard.getExtensions();
                    byte[] b = vCard.getAvatar();
                    Bitmap avatar = BitmapFactory.decodeByteArray(vCard.getAvatar(), 0, b.length);
                    avatarPath = savaAvatar(avatar, entry.getUser());
                } catch (Exception e) {
                }

                HashMap<String, String> user = new HashMap<String, String>();
                user.put("name", entry.getName());
                user.put("userid", entry.getUser());
                user.put("statusMsg", "" + entry.getStatus());
                user.put("user_avatar", avatarPath);
                user.put("status", "" + connection.getRoster().getPresence(entry.getUser()).isAvailable());
                userList.add(user);
            }
        }
        return userList;
    }