改NavigationBar背景

//  UINavBar.h
#import <Foundation/Foundation.h>


@interface UINavigationBar (UINavigationBarCategory)
UIImageView *bg;
-(void)setBackgroundImage:(UIImage*)image;
- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index;
@end





//  UINavBar.m
#import "UINavBar.h"

@implementation UINavigationBar (UINavigationBarCategory)
-(void)setBackgroundImage:(UIImage*)image {
    if(image == nil) return;
    bg = [[UIImageView alloc]initWithImage:image];
    bg.frame = CGRectMake(0.f, 0.f, self.frame.size.width, self.frame.size.height);
    [self addSubview:bg];
    [self sendSubviewToBack:bg];
    [bg release];
}

- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index
{
    [super insertSubview:view atIndex:index];
    [self sendSubviewToBack:bg];
}
@end



View Controller:

//  MyViewController.m
- (void)viewDidLoad {
    [super viewDidLoad];
    [[self.navigationController navigationBar] setBackgroundImage:[UIImage imageNamed:@"navbar.png"]];
}



返回按钮：

- (void)viewDidLoad {
    [super viewDidLoad];
    UIButton *backButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 63, 30)];
    [backButton setImage:[UIImage imageNamed:@"back.png"] forState:UIControlStateNormal];
    [backButton addTarget:self action:@selector(pushBack) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *backButtonItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
    self.navigationItem.leftBarButtonItem = backButtonItem;
    [backButtonItem release];
    [backButton release];
}