java - Android socket io get online user -

i developing android private chat application. in application, want see online user or check whether user online or not. have got reference.

emit("login",userid); 

is used online users. use

public class onlineactivity extends appcompatactivity {     private socket msocket;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_online);          chatapplication app = (chatapplication) getapplication();         msocket = app.getsocket();          jsonobject user = new jsonobject();         try {             user.put("userid", "abc");         } catch (jsonexception e) {             // todo auto-generated catch block             e.printstacktrace();         }          msocket.emit("login",user);          log.d("log", string.valueof(msocket.emit("login",user)));         log.d("log", string.valueof(user));     } } 

where abc user id, not show results. please me.

the answer shown in how check user online or not in socket io , android chat application

socket.on('isactive', function (user) { const userid = user.userid; const user = usernames[userid]; const socketid = socket.id; let response; if(user) {     // user active     response = {isactive: true}; } else {     // user not active     response = {isactive: false}; } const responsesocket = io.sockets.connected[socketid]; if(responsesocket) {     responsesocket.emit('onisactive', response); } });