ios - removing a view controller on click of a button -

i developing library ios app authenticate users on basis of credential entered them.

what doing that, view controller testviewcontroller setting new view controller loginscreenviewcontroller on top of testviewcontroller when user taps button using following code.

loginscreenviewcontroller * loginscreen = [[loginscreenviewcontroller alloc] initwithnibname:nil bundle:nil];  [self.view addsubview:loginscreen.view]; 

this loginscreenviewcontroller contains cancel button, on want remove loginscreenviewcontroller. using following code

[self.view removefromsuperview]; 

the problem when executing code, app crashing.

since loginscreenviewcontroller defined library, want independent of caller's implementation.

edit:
in loginscreenviewcontroller.m have used following code add event handler cancel button.

[button addtarget:self action:@selector(cancelbuttonhandler:) forcontrolevents:uicontroleventtouchupinside]; 

the app crashing when tapping cancel button. if cancelbuttonhandler not contain line of code.

you trying remove wrong view. remove loginscreen view do:

[loginscreen.view removefromsuperview];