which is stored in the SharesPreferences as long as the application needs it.
Why?
As soon as the user wants to exit, the password in the SharedPreferences should be wiped and of course all activities of the application should be closed (it makes no sense to run them without the known password - they would crash).
Even better: don't put the password in SharedPreferences
. Hold onto it in a static data member. The data will naturally go away when all activities in the app are exited (e.g., BACK button) or otherwise destroyed (e.g., kicked out of RAM to make room for other activities sometime after the user pressed HOME).
If you want some sort of proactive "flush password", just set the static data member to null
, and have your activities check that member and take appropriate action when it is null
.