UINavigationBar自定义返回按钮

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[self.navigationController pushViewController:self.bView animated:YES];

一开始想当然的，在B视图的viewDidLoad里直接使用：

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self.navigationItem.backBarButtonItem.title = @"back";

来更改后退按钮标题，结果后退后，发现A视图的导航栏标题也变成“back”了。

于是网上搜了一下，别人推荐在B视图的viewDidLoad/viewWillAppear里使用：

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UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"back" style:UIBarButtonItemStyleBordered target:nil action:nil];[self.navigationItem setBackBarButtonItem:backItem];[backItem release];

我试了，发现无效。

无奈之下，只好研读UINavigationController ClassReference去，在“Updating the Navigation Bar”小节，有这么一段话：

The bar button itemon the left side of the navigation bar allows for navigation backto the previous view controller on the navigation stack. Thenavigation controller updates the left side of the navigation baras follows:

• If the newtop-level view controller has a custom left bar button item, thatitem is displayed. To specify a custom left bar button item, setthe leftBarButtonItem property of the view controller’s navigationitem.
• If the top-levelview controller does not have a custom left bar button item,but the navigationitem of the previous viewcontroller has a valid item in itsbackBarButtonItem property,the navigation bar displays that item.
• If a custom barbutton item is not specified by either of the view controllers, adefault back button is used and its title is set to the value ofthe title property of the previous view controller—that is, theview controller one level down on the stack. (If there is only oneview controller on the navigation stack, no back button isdisplayed.)

我大致解释一下，使用pushViewController切换到下一个视图时，navigationcontroller按照以下3条顺序更改导航栏的左侧按钮。

1、如果B视图有一个自定义的左侧按钮（leftBarButtonItem），则会显示这个自定义按钮；

2、如果B没有自定义按钮，但是A视图的backBarButtonItem属性有自定义项，则显示这个自定义项；

3、如果前2条都没有，则默认显示一个后退按钮，后退按钮的标题是A视图的标题。

按照这个解释，我把UIBarButtonItem*backItem……这段代码放在A视图的pushViewController语句之前。

OK问题解决了，B视图的后退按钮的标题变成back了。

 

UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"back" style:UIBarButtonItemStyleBordered target:nilaction:nil]; 

[self.navigationItem setBackBarButtonItem:backItem];

  [backItem release]; 

[self.navigationController pushViewController:self.bView animated:YES];

转载自：http://zgia.net/?p=306