如何在联系人之间发送和接收状态

Question

我希望花名册中的所有联系人列表都显示为在线（如果已连接）和离线（如果未连接）。

我做了什么？ 我从xmpp服务器请求了用户名册，然后创建了IQ节以请求用户节，然后将IQ节发送到服务器，因此我收到了请求的名册，然后从响应的query元素中提取了所有名册项并将其存储在userRosterClone < / p>

const userRosterClone = this.userRoster.slice(); 

我现在要做的是在名单中显示每个用户的在线状态，因此我创建了一个功能并发送了名单

 this.requestUserPresence(userRosterClone);

 requestUserPresence(contactList): void{
  for (let i = 0 ; i<contactList.length; i++){

  console.log("Requesting the user\'s presence...");

  // 1. Creating presence stanza to request the user's contact list stanza

  const presence = $pres({
 id: generateUUIDv4(),
 to: contactList[i].contactJid,
 type: "subscribe"

   })

  console.log("presence to request the user's presence:", 
   presence.tree());

  // 2. Sending the presence stanza to the server


   this.connection.addHandler(this. 
   onReceivingRequestedPresence.bind(this), null, "presence");

   this.connection.sendPresence(presence);

    }

问题出在onReceivingRequestedPresence无法正常工作，我无法将在线状态发送到已订阅类型的花名册。

   onReceivingRequestedPresence(presence){

   console.log("Server Response to roster presence request: ", 
    presence);

   const pres= $pres({
    from: presence.to,
    id: presence.id,
    to: this.connection.jid,
    type: "subscribed"
    })

  // 2. Sending the IQ stanza to the server

this.connection.sendPresence(pres)


  }