iOS: Positioning navigation bar buttons within custom navigation bar

问题

I'm building an app with a custom navigation bar. After some research I decided to do this using a category on UINavigationBar. The navigation bar needs to be a bit larger than usual to accomodate a drop shadow. Here is the code:

#import "UINavigationBar+CustomWithShadow.h"

@implementation UINavigationBar (CustomWithShadow)

- (void)drawRect:(CGRect)rect {

    // Change the tint color in order to change color of buttons
    UIColor *color = [UIColor colorWithHue:0.0 saturation:0.0 brightness:0.0 alpha:0.0];
    self.tintColor = color;

    // Add a custom background image to the navigation bar 
    UIImage *image = [UIImage imageNamed:@"NavBar.png"];
    [image drawInRect:CGRectMake(0, 0, self.frame.size.width, 60)];
}

- (void)layoutSubviews {

    self.frame = CGRectMake(0, 20, self.frame.size.width, 60);
}
@end

The only problem now is that the larger navigation bar means that the navigation bar buttons end up too far down, like so:

Does anyone know how I can correct the position of the buttons?

Thanks for all help!

Update:

I add the buttons to the nav bar in the init method of the view controller like so:

// Create "Add" button for the nav bar
UIBarButtonItem *addButton = [[UIBarButtonItem alloc] 
    initWithBarButtonSystemItem:UIBarButtonSystemItemAdd 
    target:self 
    action:@selector(createNewEntry:)];
[[self navigationItem] setRightBarButtonItem:addButton];
[addButton release];

回答1:

You'll need to add the leftBarButtonItem and rightBarButtonItem as custom items and mess with the frames.... for example:

UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0,5,buttonImage.size.width,buttonImage.size.height)];
[button setBackgroundImage:buttonImage forState:UIControlStateNormal];
[button addTarget:delegate action:@selector(barButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
[button setTitle:titleString forState:UIControlStateNormal];
[button setTitleColor:CUSTOM_BAR_BUTTON_TITLE_COLOR forState:UIControlStateNormal];
[[button titleLabel] setFont:[UIFont boldSystemFontOfSize:14]];
[[button titleLabel] setShadowColor:CUSTOM_BAR_BUTTON_SHADOW_COLOR];
[[button titleLabel] setShadowOffset:CGSizeMake(0,-1)];

UIBarButtonItem *barButton = [[UIBarButtonItem alloc] initWithCustomView:button];
[button release];

[[self navigationItem] setRightBarButtonItem:barButton];
[barButton release];

回答2:

Try adding the buttons to the nav bar in the viewDidLoad method of the view controller instead.

回答3:

My solution, not the best, but it works for me fine. My custom navigation bar has height 55 (default height is 44). I cut from my custom navigation bar only 44 of height and insert it to the navigation bar. Then I cut next part of my custom navigation bar (shadows etc.) and insert it as image view under the navigation bar. And that's it. Buttons are at right places...

来源：https://stackoverflow.com/questions/6169474/ios-positioning-navigation-bar-buttons-within-custom-navigation-bar