xcode - How to run presentViewController in IOS static library -

i trying build static library camera in ios, showing error in user application

attempt present <uiimagepickercontroller: 0x17e2f740> on <camera: 0x17d3f5b0> view not in window hierarchy! 

i using code in camera.m inside static library libcamera.a

 -(void)callcamera  {   uiimagepickercontroller * picker = [[uiimagepickercontroller alloc] init];   picker.delegate = self;   picker.sourcetype = uiimagepickercontrollersourcetypecamera;   [self presentviewcontroller:picker animated:yes];// error line  } 

i using library in application checkcamera.m importing libcamera.a

-(void)viewdidload  {   [super viewdidload]   camera cam=[[camera alloc]init];   [cam callcamera]   } 

but showing above mentioned error, want know how run presentviewcontroller inside static library?

try move [cam callcamera] viewdidload viewdidappear. according uiviewcontroller class reference viewdidappear exact method indicates view controller's view added window hierarchy.

edited:

if camera subclass of uiviewcontroller, please try this:

- (void)viewdidappear:(bool)animated {     [super viewdidappear:animated];      camera *cam=[[camera alloc] init];      [self.view addsubview:cam.view];     [self addchildviewcontroller:cam];     [cam callcamera]; }