我正在使用jivesoftware Smack SDk进行实时聊天功能.
为了创建连接,我使用以下代码,

XMPPTCPConnectionConfiguration.Builder config = XMPPTCPConnectionConfiguration.builder();
    config.setSecurityMode(ConnectionConfiguration.SecurityMode.disabled);

    config.setServiceName("world-pc");
    config.setHost(serverAddress);
    config.setPort(5222);
    config.setDebuggerEnabled(true);
    XMPPTCPConnection.setUseStreamManagementResumptiodDefault(true);
    XMPPTCPConnection.setUseStreamManagementDefault(true);
    connection = new XMPPTCPConnection(config.build());
    XMPPConnectionListener connectionListener = new XMPPConnectionListener();
    connection.addConnectionListener(connectionListener);
    connection.connect();
    connection.login("username","password");

它的工作非常好.
现在问题是,我希望获得特定用户的在线状态或获取所有在线用户的列表.
我从堆栈溢出尝试了很多解决方案,但没有什么对我有用.
我试过的解决方案之一是,

Presence presence = new Presence(Presence.Type.available);
connection.sendPacket(presence);
Roster roster = xmppConnection.getRoster();
Collection<RosterEntry> entries = roster.getEntries();
Presence presence;

for(RosterEntry entry : entries) {
presence = roster.getPresence(entry.getUser());

System.out.println(entry.getUser());
System.out.println(presence.getType().name());
System.out.println(presence.getStatus());
 }

这会返回一个列表,但所有用户的状态为null.
请有人帮我准确解决方案.

谢谢

解决方法:

您可以使用Presence.Type.subscribe来了解(作为用户)另一个用户的状态：

Presence subscribe = new Presence(Presence.Type.subscribe);
subscribe.setTo('another_user@example.com');
connection.sendPacket(subscribe);

并且“another_user”应以同样的方式批准您的请求：

Presence subscribe = new Presence(Presence.Type.subscribe);
subscribe.setTo('another_user@example.com');
connection.sendPacket(subscribe);