How to prevent user changing system date/time (in Android)?
Here is a third alternative that should significantly save on battery life:
Register a BroadCast Receiver for when the time gets changed by the user. Then disable the app until the device time is checked against network-time or server-time.
Those Broadcast Receivers exist. I just checked now with this app called Internal Broadcast Monitor I just found on Google Play.
Here is the interesting part below where I changed both the time and the date:
And below is the part where I changed the time zone:
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I don't know of any way that you can change the default behavior of the device.
You can however prevent your application from running if the system time differs from the network time. Or you could use the network time in your app instead of system time.
The answer to this post explains how to access the network time.