Resolved by changing window level property
window.windowLevel = UIWindowLevelAlert + 1;
Question
I have Timeout screen. if UIAlertView is displaying on screen and application is ideal for some time then lock screen appears, so issue is that lock screen is going below the alert view
Solution
Resolved by changing window level property
window.windowLevel = UIWindowLevelAlert + 1;
OTHER TIPS
Hide alertView and display Timeout screen. After timeout screen dismissal display alertView again.