Both a UIImage and a "back" button appearing in my viewController - iphone

Question

I have both a UIImage and a "back" button appearing in my viewcontroller and can't figure out why.
here's a screenshot:
here's my code:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.navigationController setNavigationBarHidden:NO animated:YES];
UIImage *image = [UIImage imageNamed:#"arrow_back.png"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[self.navigationController.navigationBar addSubview:imageView];
}
thanks for any help.

Answer 1

You will have to create a backbarbutton item and add a custom to it. Then you define the action for it, where you pop the current view.
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setImage:buttonImage forState:UIControlStateNormal];
//set the frame of the button to the size of the image (see note below)
button.frame = CGRectMake(0, 0, buttonImage.size.width, buttonImage.size.height);
[button addTarget:self action:#selector(back) forControlEvents:UIControlEventTouchUpInside];
//create a UIBarButtonItem with the button as a custom view
UIBarButtonItem *customBarItem = [[UIBarButtonItem alloc] initWithCustomView:button];
self.navigationItem.leftBarButtonItem = customBarItem;
// selector for backButton
-(void)back{
[self.navigationController popViewController];
}

Answer 2

You need to create a custom button and add it as a subview of self.navigationController.navigationBar.backBarButtonItem.

Answer 3

The back button is automatic when you push a second view controller into the navigation controller. You can override it as Andrew Ebling mentioned. You will need to create a custom UIBarButton item.
UIImage *image = [UIImage imageNamed:#"back.png"];
UIBarButtonItem *back = [UIBarButtonItem alloc] initWithImage:image
style:UIBarButtonItemStylePlain
target:self
action:#selector(backEvent:)];
self.navigationItem.backBarButtonItem = back;