iphone UINavigationBar 自定义返回按钮

很多时候我们使用navigationController时由于上一个navigationController.title的字符串太长，而导致下一个界面的返回按钮变的很长也很难看，为了美观我们我们可以把返回按钮的title改为back，或者是用自定义的图片。 

1.把返回按钮的title改为back：这里要特别说明一下，需要在上一个viewController里面写上以下代码。若是在当前viewController中无论你是用self.navigationItem.leftBarButtonItem.title = @"back"; 还是用self.navigationItem.backBarButtonItem.title = @"back"; 都不会修改返回按钮的title。代码如下： 

- (void)back:(id)sender {
 [self.navigationController popViewControllerAnimated:YES];
}
  
// The designated initializer. Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
-(id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
// 下一个界面的返回按钮
UIBarButtonItem *temporaryBarButtonItem = [[UIBarButtonItem alloc] init];
temporaryBarButtonItem.title = @"back";
temporaryBarButtonItem.target = self;
temporaryBarButtonItem.action = @selector(back:);
self.navigationItem.backBarButtonItem = temporaryBarButtonItem;
[temporaryBarButtonItem release];
}
return self;
}

.用自定义的图片修改返回按钮：

-(IBAction)backAction{
 [self.navigationController popViewControllerAnimated:YES];
}
 // The designated initializer. Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
 if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
 // Custom initialization
 UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
 backButton.frame = CGRectMake(0.0, 0.0, 40.0, 27.0);
 [backButton setImage:[UIImage imageNamed:@"Btn_Back_Off.png"] forState:UIControlStateNormal];
 [backButton setImage:[UIImage imageNamed:@"Btn_Back_On.png"] forState:UIControlStateSelected];
 [backButton addTarget:self action:@selector(backAction) forControlEvents:UIControlEventTouchUpInside];
 UIBarButtonItem *temporaryBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
 temporaryBarButtonItem.style = UIBarButtonItemStylePlain;
 self.navigationItem.leftBarButtonItem=temporaryBarButtonItem;
[temporaryBarButtonItem release];
}
return self;
}

原文地址：http://blog.csdn.net/jinglijun/article/details/7001356