How to get Firebase Realtime Database server time with Kotlin in Android

Question

I need to get Firebase Database current milliseconds epoch time in Kotlin Android app, i tried to push the value to firebase and then read it, i have a button calls a function named pushEndTime() then calls read() but it always get's null value on the first click then on the second click it get's the past value of endTime

this is the code:

private fun pushEndTime(){
    rootRef.child("user/endTime").setValue(ServerValue.TIMESTAMP)
}

then i read it using

private fun read(){
    rootRef.child("user/endTime").addValueEventListener(
        object : ValueEventListener {
            override fun onDataChange(dataSnapshot: DataSnapshot) {

                endTime = dataSnapshot.value.toString()

            }

            override fun onCancelled(databaseError: DatabaseError) {
                Log.w(TAG, "LoginData:onCancelled", databaseError.toException())
                Toast.makeText(this@HomeFragment.context, "Error! check your internet", Toast.LENGTH_LONG)
                .show()
            }
        })
}

i use these methods in onActivityCreated like this :

button.setOnClickListener {
    pushEndTime()
    read()
}

i can't put pushEndTime() in onActivityCreated, it has to be inside a function creates endTime once the button is clicked and some other values checked, but i also tried to put it inside on create and still returns null result on the first button click

I found some answers here suggesting to use Firebase.database.ServerValue.TIMESTAMP but it dosen't work for me

this is how i used it: endTime = ServerValue.TIMESTAMP.getValue(".sv") but it returns this value and not the epoch time: Timestamp

i tried this: Firebase.database.ServerValue.TIMESTAMP.getValue(".sv") but it shows unresolved reference: ServerValue error

also i tried it like this: Firebase.database.reference.ServerValue.TIMESTAMP.getValue(".sv") and the same unresolved reference error

com.google.firebase.database.ServerValue is imported

I need to get firebase server time, if there is defiantly no way, how to get the internet time in kotlin?

Your code is correct. How do you call these methods. Can you share it? — Kasım Özdemir, May 19 '20 at 21:03
I think the main problem is, when you click on button to load server time from Firebase, it take time to response. You should implement async to await for the Firebase response. — Mohamed Mamun, May 19 '20 at 21:09
To get real time/date use my answer https://stackoverflow.com/a/73029062/4965949 — Mahmoud Mabrok, Jul 18 '22 at 22:01

score 1 · Accepted Answer · answered May 19 '20 at 21:14

1

You can try this:

private fun pushEndTime(){
    rootRef.child("user/endTime").setValue(ServerValue.TIMESTAMP).addOnSuccessListener {
        read()
    }
}

private fun read(){
    rootRef.child("user/endTime").addListenerForSingleValueEvent(
        object : ValueEventListener {
            override fun onDataChange(dataSnapshot: DataSnapshot) {

              endTime = dataSnapshot.value.toString()

            }

            override fun onCancelled(databaseError: DatabaseError) {
                Log.w("SignedActivity.TAG", "LoginData:onCancelled", databaseError.toException())

            }
        })
}

Call read method when setValue is success

answered May 19 '20 at 21:14

Kasım Özdemir

5,414
3
18
35

still getting null on the first click, i used it like this: button.setOnClickListener { pushEndTime() } then i print it, but still getting null value from firebase realtime database – Obada Zayadneh May 20 '20 at 12:16
Thanks, the last problem was that i used endTime variable inside another function called after pushEndTime(), i had to declare endTime globally, so that it kept returning null which is the deceleration value, until it gets the response, i have called checkout function inside on onDataChange in read() after getting endTime value to make sure endTime value has changed – Obada Zayadneh May 20 '20 at 15:29

How to get Firebase Realtime Database server time with Kotlin in Android

1 Answers1