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?

Answer 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