当前左边栏按钮的默认值是加载当前视图的视图的标题,换句话说,当按下按钮(后退按钮)时显示的视图。

我想把按钮上显示的文本更改为其他内容。

我试着把下面这行代码放在视图控制器的viewDidLoad方法中,但它似乎不起作用。

self.navigationItem.leftBarButtonItem.title = @"Log Out";

我该怎么办?

谢谢。


当前回答

UIBarButtonItem *btnBack = [[UIBarButtonItem alloc]
                                   initWithTitle:@"Back" 
                                   style:UIBarButtonItemStyleBordered
                                   target:self
                                   action:@selector(OnClick_btnBack:)];
    self.navigationItem.leftBarButtonItem = btnBack;
    [btnBack release];

其他回答

下面是backBarButtonItem的文档:

时,此导航项位于顶部项的正下方 堆栈时,导航控制器派生返回按钮 此导航项中的导航栏。[…如果你想的话 为后退按钮指定自定义图像或标题,则可以指定 自定义栏按钮项目(与您的自定义标题或图像)到此 财产。”

视图控制器A(父视图控制器):

self.title = @"Really Long Title";
UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:@"Short" style:UIBarButtonItemStyleBordered target:nil action:nil];
self.navigationItem.backBarButtonItem = backButton;

当任何其他视图控制器B在导航堆栈的顶部,而A在它的正下方时,B的后退按钮的标题将是“Short”。

问题:导航栏中的“返回”文本不能被替换。

原因:在推送视图后,导航栏中设置了“Back”标签,因为父视图控制器中的.title属性被设置为nil(或未初始化)。

一个解决方案:如果你设置self.title="Whatever…",你会看到在按下新的视图控制器后,"Back"将出现"Whatever…"。

斯坦的回答是最好的。但它也有一个问题,当你使用带有标签栏的控制器并更改控制器的标题时,你也可以更改标签栏的标题。所以最好的答案是改变view_controller。navigationitem。只使用view_controller.navigationItem。函数中的标题。 答案在这里:(使用ARC并将它们添加到视图的viewDidLoad中)

  static NSString * back_button_title=@"Back"; //or whatever u want
  if (![view_controller.navigationItem.title isEqualToString:back_button_title]){
    UILabel* custom_title_view = [[UILabel alloc] initWithFrame:CGRectZero];
    custom_title_view.text = view_controller.navigationItem.title; // original title
    custom_title_view.font = [UIFont boldSystemFontOfSize:20];
    custom_title_view.backgroundColor = [UIColor clearColor];
    custom_title_view.textColor = [UIColor whiteColor];
    custom_title_view.shadowColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.5];
    custom_title_view.shadowOffset = CGSizeMake(0, -1);

    [custom_title_view sizeToFit];

    view_controller.navigationItem.titleView = custom_title_view;
    view_controller.navigationItem.title = back_button_title;
  }

在我自己的使用中,我使它成为一个这样的函数,只是在viewDidLoad中有一行代码的特性。

+ (void)makeSubViewHaveBackButton:(UIViewController*) view_controller{
  static NSString * back_button_title=@"Back"; //or whatever u want
  if (![view_controller.navigationItem.title isEqualToString:back_button_title]){
    UILabel* custom_title_view = [[UILabel alloc] initWithFrame:CGRectZero];
    custom_title_view.text = view_controller.navigationItem.title; // original title
    custom_title_view.font = [UIFont boldSystemFontOfSize:20];
    custom_title_view.backgroundColor = [UIColor clearColor];
    custom_title_view.textColor = [UIColor whiteColor];
    custom_title_view.shadowColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.5];
    custom_title_view.shadowOffset = CGSizeMake(0, -1);

    [custom_title_view sizeToFit];

    view_controller.navigationItem.titleView = custom_title_view;
    view_controller.navigationItem.title = back_button_title;
  }
}

这应该放在调用名为NewTitle的ViewController的方法中。 就在push或popViewController语句之前。

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

Most of solutions kills the original style of BackButton (The left arrowed bar button) while adding a usual button with desired title. So to keep the original style there are 2 ways: 1st: To use undocumented button style (110 or something like that) which I prefer not to do. But if you want you could find how to do it here, on stackoverflow. 2nd: To use I the Trenskow's idea. I liked it and I use it a bit changed. Instead of overriding - (NSString*)title I've decided to keep the original title in the following way (which allows me to use nib's titles as well as given title at push state btw).

- (void)viewDidLoad {
    [super viewDidLoad];
    static NSString * backButtonTitle=@"Back"; //or whatever u want

    if (![self.title isEqualToString:backButtonTitle]){

        UILabel* customTitleView = [[UILabel alloc] initWithFrame:CGRectZero];
        customTitleView.text = self.title; // original title
        customTitleView.font = [UIFont boldSystemFontOfSize:20];
        customTitleView.backgroundColor = [UIColor clearColor];
        customTitleView.textColor = [UIColor whiteColor];
        customTitleView.shadowColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.5];
        customTitleView.shadowOffset = CGSizeMake(0, -1);

        [customTitleView sizeToFit];

        self.navigationItem.titleView = [customTitleView autorelease];
        self.title = backButtonTitle; 
    }
}

这个解决方案效果很好,看起来很自然。此外,如果在viewDidLoad方法中使用它,它可以防止执行超过1次。 我也试过杰塞德克的解决方案,但看起来很糟糕。它导致可见的用户标题栏的变化,从原来的BackButton的期望和回来。