changing UIBarButtonItem UIButton's image - iphone

Question

I have a UIBarButtonItem with a custom view of a UIbutton with an image, I want to have a different UIImage for different orientation, so here's my code:
UIButton * backButton = (UIButton *) ((UIBarButtonItem *) self.navBar_.topItem.leftBarButtonItem).customView;
if (UIInterfaceOrientationIsLandscape([[UIApplication sharedApplication] statusBarOrientation]) && IS_IPAD) {
[backButton setBackgroundImage:[UIImage imageNamed:#"back-landscape.png"] forState:UIControlStateNormal];
[backButton setFrame: CGRectMake(0, 0, 46, 35)];
} else {
[backButton setBackgroundImage:[UIImage imageNamed:#"back-reading.png"] forState:UIControlStateNormal];
[backButton setFrame: CGRectMake(0, 0, 23, 19)];
}
However this doesn't change the UIButton image, why is this?

Answer 1

Try this:-
UIButton * backButton ;
if (UIInterfaceOrientationIsLandscape([[UIApplication sharedApplication] statusBarOrientation]) && IS_IPAD)
{
backButton = [[UIButton alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 66.0f, 36.0f)];
[backButton setImage:[UIImage imageNamed:#"back-landscape.png"] forState:UIControlStateNormal];
}
else
{
backButton = [[UIButton alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 23, 19)];
[backButton setImage:[UIImage imageNamed:#"back-reading.png"] forState:UIControlStateNormal];
[backButton setFrame: CGRectMake(0, 0, 23, 19)];
}
[backButton addTarget:self action:#selector(goToHome) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *HomeButton = [[UIBarButtonItem alloc] initWithCustomView: backButton];
[self.navigationItem setLeftBarButtonItem:HomeButton];

Answer 2

You should notify that you say it is a UIBarButtonItem , but you use UIButton in code.
From ios5.0, you can use UIAppearence Protocol to change UIBarButtonItem background image, like:
[[UIBarButtonItem appearance] setBackgroundImage: forState: barMetrics:]
You can also use elppa's method, but notice you can directly use UIImageView for the customView parameter.

Answer 3

You could use the new proxy class with +appereance method check the DOC, but is only for iOS5. For earlier support you can update the image while the view is rotating the view controller method -willRotateToInterfaceOrientation.
Ciao

Answer 4

Create a UIBarButton using a custom UIButton:
_optionsButton = [UIButton buttonWithType:UIButtonTypeCustom];
[_optionsButton setImage:[UIImage imageNamed:#"menu2.png"] forState:UIControlStateNormal];
[_optionsButton addTarget:self action:#selector(optionsButtonPressed) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem * optionsItem = [[UIBarButtonItem alloc] initWithCustomView:_optionsButton];
Then set a background image as you would normally for that UIButton (instead of trying to change the image for the UIBarButton).
[_optionsButton setImage:[UIImage imageNamed:#"keyboard.png"] forState:UIControlStateNormal];
This worked great for me
Note: When I was going through this I was changing the picture depending on what the current picture was. I found I had to use:
if ([[_optionsButton imageForState:UIControlStateNormal] isEqual:[UIImage imageNamed: #"keyboard.png"]]) {
// Code for the certain button function
}
to get it to work