UIPopoverController for iPad "must not be called with `nil`" error - ios

Question

I am trying to make an iPhone app work in an iPad but the UIPopoverController is
comming back with error.
- (IBAction)photoTapped1 {
if(UI_USER_INTERFACE_IDIOM()== UIUserInterfaceIdiomPhone){
// If in editing state, then display an image picker; if not, create and push a photo view controller.
if (self.editing) {
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
imagePicker.delegate = self;
[self presentViewController:imagePicker animated:YES completion:nil];
[imagePicker release];
} else {
RecipePhotoViewController *recipePhotoViewController = [[RecipePhotoViewController alloc] init];
recipePhotoViewController.hidesBottomBarWhenPushed = YES;
recipePhotoViewController.recipe = recipe;
[self.navigationController pushViewController:recipePhotoViewController animated:YES];
[recipePhotoViewController release];
}
}else{
if (self.editing){
self.popover = [[UIPopoverController alloc] initWithContentViewController:popover];
self.popover.delegate =self;
[popover release];
}else{
RecipePhotoViewController *recipePhotoViewController = [[RecipePhotoViewController alloc] init];
recipePhotoViewController.hidesBottomBarWhenPushed = YES;
recipePhotoViewController.recipe = recipe;
[self.navigationController pushViewController:recipePhotoViewController animated:YES];
[recipePhotoViewController release];
}}}
The error I am getting is:
'NSInvalidArgumentException', reason: '-[UIPopoverController initWithContentViewController:] must not be called with nil.'
Anyone available to give me a hand on this code, I have looked on the internet for solutions and samples but can not seem to make it work.
Thank you.
___ added to original question_____
I am adding the recipePhotoViewController here, I am assuming that ImageView manipulation is the same for iPhone and iPad.
my.h File
#class Recipe;
#interface RecipePhotoViewController : UIViewController {
#private
Recipe *recipe;
UIImageView *imageView;
}
#property(nonatomic, retain) Recipe *recipe;
#property(nonatomic, retain) UIImageView *imageView;
#end
Here is my .m file
#implementation RecipePhotoViewController
#synthesize recipe;
#synthesize imageView;
- (void)loadView {
self.title = #"Photo";
imageView = [[UIImageView alloc] initWithFrame:[UIScreen mainScreen].applicationFrame];
imageView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
imageView.contentMode = UIViewContentModeScaleAspectFit;
imageView.backgroundColor = [UIColor blackColor];
self.view = imageView; }
- (void)viewWillAppear:(BOOL)animated {
imageView.image = [recipe.image valueForKey:#"image"];}
- (BOOL)shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation)interfaceOrientation {
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}
- (void)dealloc {
[imageView release];
[recipe release];
[super dealloc];
} #end

Answer 1

You are initializing the popover controller in a wrong way:
self.popover = [[UIPopoverController alloc] initWithContentViewController:popover];
You should pass the controller you would like to display inside of the popover -- not the popover itself (which is nil since you have not yet initialised it)!
Maybe this would do it for you?
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
imagePicker.delegate = self;
self.popover = [[UIPopoverController alloc] initWithContentViewController:imagePicker];
If this is correct, then you should also present the pop over you have just created: – presentPopoverFromRect:inView:permittedArrowDirections:animated:
-- e.g.:
[self.popover presentPopoverFromRect:sender.frame inView:[self view] permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
where sender is the argument to :
- (IBAction)photoTapped1:(id)sender {

Answer 2

The content of your popover which you store in the variable popover is obviously nil. I can't see it ever being created in the code you provided.
Maybe you intended to present the Recipe photo controller as the content of the popover. In that case you would do something like
RecipePhotoViewController *recipePhotoViewController = [[RecipePhotoViewController alloc] init];
self.popover = [[UIPopoverController alloc] initWithContentViewController:recipePhotoViewController];

Answer 3

problem is in this line of your code ,
self.popover = [[UIPopoverController alloc] initWithContentViewController:popover];
try like this
UIViewController* popoverContent = [[UIViewController alloc] init];
UIView* popoverView = [[UIView alloc] initWithFrame:CGRectMake(0, 400, 320, 260)];
popoverContent.view = popoverView;
//Add what ever you want popoverView
self.popover = [[UIPopoverController alloc] initWithContentViewController:popoverContent];
self.popover.delegate =self;