Variables not kept when changed in a callback - ios

Question

I am making a game made in C++ which at some point wants to open make use of the camera.
To do this it interfaces with an Objective C class which presents the modal view controller:
UIImagePickerController* cameraUI = [[UIImagePickerController alloc] init];
cameraUI.sourceType = UIImagePickerControllerSourceTypeCamera;
cameraUI.mediaTypes = [[NSArray alloc] initWithObjects:(NSString*)kUTTypeImage, nil];
cameraUI.allowsEditing = YES;
cameraUI.delegate = self;
[[[[UIApplication sharedApplication] keyWindow] rootViewController] presentModalViewController:cameraUI animated:YES];
This class exposes a State variable to allow the game to watch the progress of the modal view controller.
It is initalized:
State = CAMERA_ACTIVITY_WORKING;
And updated by the UIImageControllerDelegate functions:
- (void)imagePickerControllerDidCancel: (UIImagePickerController*) picker
{
State = CAMERA_ACTIVITY_CANCELED;
[[[[UIApplication sharedApplication] keyWindow] rootViewController] dismissModalViewControllerAnimated:YES];
[picker release];
}
- (void)imagePickerController: (UIImagePickerController*) picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
State = CAMERA_ACTIVITY_IMAGECAPTURED;
[[[[UIApplication sharedApplication] keyWindow] rootViewController] dismissModalViewControllerAnimated:YES];
[picker release];
}
The modal view controller opens and closes as it should and the delegates definately get called. However, when the game polls the State variable it appears to have not been updated returning CAMERA_ACTIVITY_WORKING.
I have tried making the variable volatile but this had no effect.
Can anybody help?
Edit: Full Class Source Code
.h
#interface Camera : UIViewController<UIImagePickerControllerDelegate, UINavigationControllerDelegate>
{
volatile State State;
UIImage* CapturedImage;
}
- (void)imagePickerControllerDidCancel: (UIImagePickerController*) picker;
- (void)imagePickerController: (UIImagePickerController*) picker didFinishPickingMediaWithInfo:(NSDictionary *)info;
- (bool) IsAvailable;
- (bool) Show;
- (State) GetState;
#end
.m
#implementation Camera
- (id)init
{
self = [super init];
if(!self) return self;
State = CAMERA_ACTIVITY_WORKING;
CapturedImage = NULL;
return self;
}
- (void)imagePickerControllerDidCancel: (UIImagePickerController*) picker
{
DEBUG_LOG("imagePickerControllerDidCancel");
State = Poppet::ICameraActivity::CAMERA_ACTIVITY_CANCELED;
DEBUG_LOG("State: " + STRING_CAST(State));
[[[[UIApplication sharedApplication] keyWindow] rootViewController] dismissModalViewControllerAnimated:YES];
[picker release];
}
- (void)imagePickerController: (UIImagePickerController*) picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
State = CAMERA_ACTIVITY_IMAGECAPTURED;
[[[[UIApplication sharedApplication] keyWindow] rootViewController] dismissModalViewControllerAnimated:YES];
[picker release];
}
- (bool) IsAvailable
{
return [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] == YES;
}
- (bool) Show
{
if(![self IsAvailable]) return false;
State = CAMERA_ACTIVITY_WORKING;
UIImagePickerController* cameraUI = [[UIImagePickerController alloc] init];
cameraUI.sourceType = UIImagePickerControllerSourceTypeCamera; //Get Image From Camera
cameraUI.mediaTypes = [[NSArray alloc] initWithObjects:(NSString*)kUTTypeImage, nil];
cameraUI.allowsEditing = YES;
cameraUI.delegate = self;
[[[[UIApplication sharedApplication] keyWindow] rootViewController] presentModalViewController:cameraUI animated:YES];
return true;
}
- (State) GetState
{ return State; }
#end

Answer 1

It looks like your not using your custom Camera class.
You create a class
UIImagePickerController* cameraUI = [[UIImagePickerController alloc] init];
set the delegate and some other items and display it to the user. But this is not an instance of a Camera class, it's an instance of UIImagePickerController. I believe you want to do
Camera* cameraUI = [[Camera alloc] init];
which will give you the implementation of your custom UIViewController however there is a another problem. Your Camera class is not a sub-class of UIImagePickerController, it is a sub-class of UIViewController so it will not be a UIImagePickerController. I think you intended it to be
#interface Camera : UIImagePickerController<UIImagePickerControllerDelegate, UINavigationControllerDelegate>
On a side note, naming convention says only Class names should start with capital letters. Method names and variables should start with lower case letters.
Edit from comment:
Your Show method doesn't appeared to be called from anywhere, so I'm not sure how it would be used. More than that, looking at the method, I'm not sure how it would be used. The - at the beginning means it's an instance method which can only be called on an instance of Camera, but it is used to create and show an instance of Camera so the method requires and instance of an object to create and display a newly created instance of the object. Probably not what is intended. You could use a + to make it a class method and call it with [Camera Show], but you wouldn't be able to access instance variables because they would not exist.
Currently, I don't see anywhere where a Camera is created (outside Show) and could become the active view controller so it looks like you are just displaying a generic UIImagePickerController and not your custom class.