How to protect application from substitution of local time?

Question

Android

The situation is the following. There is an application in which it is possible to work without connecting to the Internet, at this time all operations in the application are recorded according to the time of the phone, and after the appearance of the network, everything is sent to the server en masse.
I guessed to attach a broadcast receiver to ACTION_TIMEZONE_CHANGED and ACTION_TIME_CHANGED, but it already works after the fact - i.e. after the user has changed the time and it is not clear how to find out how much time has left.
Submit an implementation idea.

Answer 1

Why not use server time.
При появлении связи, синхронизируешь время.

object ServerTime {

    private var serverOffset: Long = System.currentTimeMillis() - SystemClock.elapsedRealtime()

    fun getTime(): Long = SystemClock.elapsedRealtime() + serverOffset

    fun syncTime(serverTime: Long) {
        serverOffset = serverTime - SystemClock.elapsedRealtime()
    }
}