UIImagePIckerController appears but the camera does not start - objective-c

Question

Yes, It might be a duplicate question of this. But since it didn't get an answer, I will be more specific on the case and code:
I have 3 involved UIViewControllers:
WelcomeView - the first one
TakePhotoViewController - the second one who is delegate of the OverlayviewController
OverlayViewController - custom view for the camera.
Scenario:
User enter WelcomeView and clicks on a button to be transfered with segue to TakeView.
UIImageViewController is being opened to take a photo.
The user clicks on cancel button - didCancelCamera method in TakePhotoViewController is being invoked and he returns to WelcomeView
The user leaves the app.
The user re-opens the app and perform step 1 again.
THE IMAGE PICKER IS NOT BEING OPENED. I COULD TAKE A PHOTO AND IT'S OK - BUT THE USER CAN'T SEE WHAT HE IS TAKING.
OverlayViewController.h
#interface OverlayViewController : BaseViewController<UIImagePickerControllerDelegate,UINavigationControllerDelegate>
#property (nonatomic,weak) id<OverlayViewControllerDelegate> delegate;
#property (nonatomic,retain) UIImagePickerController *imagePickerController;
#end
OverlayViewController.m:
- (id)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self) {
self.imagePickerController = [[UIImagePickerController alloc] init];
self.imagePickerController.delegate = self;
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.view.backgroundColor = [UIColor clearColor];
}
- (IBAction)takePicture:(id)sender {
[self.imagePickerController takePicture];
}
- (IBAction)cancelImagePicker:(id)sender {
[self.delegate didCancelCamera];
}
- (void) setupImagePicker:(UIImagePickerControllerSourceType) sourceType
{
self.imagePickerController.sourceType = sourceType;
if (sourceType == UIImagePickerControllerSourceTypeCamera)
{
self.imagePickerController.showsCameraControls = NO;
if ([[self.imagePickerController.cameraOverlayView subviews] count] ==0)
{
CGRect overlayViewFrame = self.imagePickerController.cameraOverlayView.frame;
CGRect newFrame = CGRectMake(0.0, CGRectGetHeight(overlayViewFrame)-self.view.frame.size.height-10.0, CGRectGetWidth(overlayViewFrame), self.view.frame.size.height + 10.0);
self.view.frame = newFrame;
[self.imagePickerController.cameraOverlayView addSubview:self.view];
}
}
}
- (void)finishAndUpdate
{
[NSThread detachNewThreadSelector:#selector(threadStartAnimating:) toTarget:self withObject:nil];
[self.delegate didFinishWithCamera]; // tell our delegate we are done with the camera
}
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
[self finishAndUpdate];
}
TakePhotoViewController.h
#interface TakePhotoViewController : BaseViewController<UIImagePickerControllerDelegate,UINavigationControllerDelegate,OverlayViewControllerDelegate>
#property (nonatomic, retain) OverlayViewController *overlayViewController;
#end
TakePhotoViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
UIStoryboard *sb = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
// Insert the overlay
self.overlayViewController = (OverlayViewController *)[sb instantiateViewControllerWithIdentifier:#"Overlay"];
self.overlayViewController.delegate = self;
}
- (void)viewDidUnload
{
self.overlayViewController = nil;
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (void)openImagePicker {
if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){
[self showImagePicker:UIImagePickerControllerSourceTypeCamera];
}
else{
[self showImagePicker:UIImagePickerControllerSourceTypePhotoLibrary];
}
}
- (void)viewDidAppear:(BOOL)animated{
if (appDelegate.shouldOpenPicker){
[self openImagePicker];
}
}
- (void)showImagePicker:(UIImagePickerControllerSourceType)sourceType
{
if ([UIImagePickerController isSourceTypeAvailable:sourceType])
{
[self.overlayViewController setupImagePicker:sourceType];
[self presentViewController:self.overlayViewController.imagePickerController animated:YES completion:nil];
}
}
-(void)didCancelCamera{
[[self.overlayViewController.imagePickerController presentingViewController] dismissViewControllerAnimated:NO completion:^ {
[self performSegueWithIdentifier:#"fromTakeToWelcome" sender:self];
}];
}

Answer 1

I found the bug.
The method
-(void)didCancelCamera from TakePhotoViewController is being called when the user clicks on - (IBAction)cancelImagePicker:(id)sender in OverlayViewController.
However, somehow the code in didCancelCamera causes viewDidAppear method of TakePhotoViewController to be invoked again and reopen the image picker.
I have no idea why
[[self.overlayViewController.imagePickerController presentingViewController] dismissViewControllerAnimated:NO completion:^ {
[self performSegueWithIdentifier:#"fromTakeToWelcome" sender:self];
}];
causes the viewDidAppear method of that view (TakePhoto) being recalled again.
Hope that it will help someone