UIImagePickerController startVideoCapture with custom overlay - iphone

Question

I am using UIImagePickerController with a custom overlay to record a video in my app. For the implementation of the UIImagePickerController, I have used the code from a great Ray Wenderlich tutorial.
I have hidden the controls for the camera, and created a simple custom overlay view. This has worked and loads fine.
I have then created a toolbar and buttons for the view, to record the video:
- (BOOL) startCameraControllerFromViewController: (UIViewController*) controller
usingDelegate: (id <UIImagePickerControllerDelegate,
UINavigationControllerDelegate>) delegate {
if (([UIImagePickerController isSourceTypeAvailable:
UIImagePickerControllerSourceTypeCamera] == NO)
|| (delegate == nil)
|| (controller == nil))
return NO;
UIImagePickerController *cameraUI = [[UIImagePickerController alloc] init];
cameraUI.sourceType = UIImagePickerControllerSourceTypeCamera;
// Displays a control that allows the user to choose movie capture
cameraUI.mediaTypes = [[NSArray alloc] initWithObjects: (NSString *) kUTTypeMovie, nil];
// Hides the controls for moving & scaling pictures, or for
// trimming movies. To instead show the controls, use YES.
cameraUI.allowsEditing = NO;
cameraUI.delegate = delegate;
//Overlay view and toolbar setup
// creating overlayView
UIView* overlayView = [[UIView alloc] initWithFrame:cameraUI.view.frame];
// letting png transparency be
float width = 320;
float AR = (4.0/3.0);
float toolbar_height = 480 - (AR*width);
UIToolbar *toolBar=[[UIToolbar alloc]initWithFrame:CGRectMake(0, (AR*width), 320, toolbar_height)];
//toolBar.tintColor = [UIColor colorWithRed:(252/255.) green:(0/255.) blue:(48/255.) alpha:1];
toolBar.tintColor = [UIColor colorWithRed:(49/255.) green:(52/255.) blue:(49/255.) alpha:1];
UIBarButtonItem *flexibleSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
UIBarButtonItem *RecordBarButtonItem = [[UIBarButtonItem alloc ] initWithBarButtonSystemItem:UIBarButtonSystemItemCamera target:self action:#selector(recordPressed:)];
UIBarButtonItem *CancelBarButtonItem = [[UIBarButtonItem alloc ] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:#selector(imagePickerControllerDidCancel:)];
NSArray *buttons = [NSArray arrayWithObjects: CancelBarButtonItem, flexibleSpace, RecordBarButtonItem, flexibleSpace, nil];
[toolBar setItems: buttons animated:NO];
[overlayView addSubview:toolBar];
[overlayView.layer setOpaque:NO];
overlayView.opaque = NO;
cameraUI.showsCameraControls = NO;
cameraUI.cameraOverlayView = overlayView;
[controller presentViewController: cameraUI animated: YES completion:nil];
return YES;
}
My button recordBarButtonItem calls recordPressed which is given by:
- (void) recordPressed: (UIImagePickerController *) picker {
NSLog(#"lets record");
[picker startVideoCapture];
}
So the 'lets record' appears on the log, but I receive an NSInvalidArgumentException error for the startVideoCapture. I know theres something obviously wrong with the way im trying to start the video capture through the button press, but I cant figure it out. Still quite a novice at iOS so forgive me if the solution is simple!
Cheers,
Mike

Answer 1

The problem is that the action you attach to the initWithBarButtonSystemItem call doesn't pass the UIImagePickerController instance along.
What I would do is set the UIImagePickerController as a property of your class and access that property from your action, like this:
In your .h:
#property (nonatomic, strong) UIImagePickerController *cameraUI;
In your .m:
- (BOOL) startCameraControllerFromViewController: (UIViewController*) controller
usingDelegate: (id <UIImagePickerControllerDelegate,
UINavigationControllerDelegate>) delegate {
...
self.cameraUI = [[UIImagePickerController alloc] init];
...
UIBarButtonItem *RecordBarButtonItem = [[UIBarButtonItem alloc ] initWithBarButtonSystemItem:UIBarButtonSystemItemCamera target:self action:#selector(recordPressed)]; // Removed the ':'
...
}
- (void) recordPressed {
NSLog(#"lets record");
[self.cameraUI startVideoCapture];
}

Answer 2

Actually I've just quickly tested it in some code I've gotten open, the sender for your action on the button press is UIBarButtonItem *. So there's a couple of things you can do, you can either go down the root of
UIBarButtonItem *senderButton = (UIBarButtonItem *)sender;
if(senderButton.image == UIBarButtonSystemItemCamera)
{
//Handle behaviour
}
Or set the tag variable for each button and skip the image check and look at the tags instead, which might make the logic a bit easier.