设置导航栏的背景图像

Question

In my UINavigationController I have added an add button through the storyboard. My add button is the default "+" UIBarButtonItem from iOS/xcode. I would like to add a custom background image to the button. My codes is not working: the background image is not added.

-(void)addBackgroundToPlusSign
{
    UIImage *addBkg = [UIImage imageNamed:@"plus_sign"];
    addBkg = [addBkg imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    [self.navigationItem.rightBarButtonItem setBackButtonBackgroundImage:addBkg forState:UIControlStateNormal barMetrics:0];
}

I try calling the method in viewDidLoad and then in viewWillAppear . No luck.

Answer 1

Your issue is that you are setting the back button's background image on the right nav button... The right navigation button is not the back button. From the documentation:

This modifier applies only to navigation bar back buttons and is ignored by other buttons.

You want to use setBackgroundImage:forState:barMetrics:

Answer 2

You can add UIImageView or button example:

UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(100, 0, 70, 30)];

[button setImage:[UIImage imageNamed:@"plus_sign"] forState:UIControlStateNormal];
[button addTarget:self action:@selector(your_method) forControlEvents:UIControlEventTouchUpInside];

UIBarButtonItem *buttonItem = [[UIBarButtonItem alloc] initWithCustomView:button];

self.navigationItem.rightBarButtonItem = buttonItem;

Answer 3

try doing:

UIBarButtonItem * addBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(btnHandler:)];

UIImage *addBkg = [UIImage imageNamed:@"plus_sign"];
addBkg = [addBkg imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
[addBtn setBackgroundImage:addBkg forState:UIControlStateNormal barMetrics:0];

self.navigationItem.rightBarButtonItem = addBtn;

I think there used to be a bug where setting the background of an existing button didn't work until the view was re-added to the view stack. You could also try just doing:

self.navigationItem.rightBarButtonItem = self.navigationItem.rightBarButtonItem;