iphone - ELCUIApplication timeout issue -

i new ios.

i have app in have login. after login user can use application.

now have functionality if user have no user intraction 2 mins app navigate login screen.

i have used -

http://www.icodeblog.com/2011/09/19/timing-out-an-application-due-to-inactivity/

for implementing it.

everything working fine expect when user login in app , use apple button app in background , not uses device few minutes , iphone in lock mode.

now if user open lock , open app, can see black screen,ui not present on there.

but if click on keyboard shown login screen's textview nothing visible.

my code of main.m

nsautoreleasepool *pool = [[nsautoreleasepool alloc] init];     int retval = uiapplicationmain(argc, argv, @"elcuiapplication", nil);     [pool release];     return retval; 

when ever timer of inactivity fires pop view controller root.

thanks help.

first check background color.

if black, make clear color.

i had similar problem , solved way.