导航栏返回按钮消失

Question

我用下面的代码来导航栏上显示的UIImage

-(void)hideTopBanner:(bool)b; 
{ 
    if(b) 
    { 

     [UIView animateWithDuration:0.35 animations:^{ 

     UIView *bannerView =[self.navigationController.navigationBar viewWithTag:999]; 
      [bannerView setFrame:CGRectMake(-320, 8, 144, 30)]; 


     }]; 
    } 
    else { 

     [UIView animateWithDuration:0.35 animations:^{ 



      UIView *bannerView =[self.navigationController.navigationBar viewWithTag:999]; 
      [bannerView setFrame:CGRectMake(88 , 8, 144, 30)]; 



     }]; 
    } 
} 

// --------------

UIImageView *bgImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"topbg1.png"]] ; 
[bgImageView setFrame:CGRectMake(0, 0, 320, 46)]; 
[self.navigationController.navigationBar addSubview:bgImageView]; 
bgImageView.tag=999; 
[bgImageView release]; 

我尝试使用

UIBarButtonItem *myBarButtonItem = [[UIBarButtonItem alloc] init]; 
    myBarButtonItem.title = @back"; // or whatever text you want 
    self.navigationItem.backBarButtonItem = myBarButtonItem; 
    [myBarButtonItem release]; 

显示后退按钮，但没有显示

但是当它导航到另一个视图控制器。 导航栏上的后退按钮消失。

欢迎任何评论

Answer 1

确保你的新视图控制器（你导航到一个）有一个标题。当我的观点没有设置标题时，我遇到了这个问题。

Answer 2

如果一切失败（设置标题等），使用此：

UIBarButtonItem *myBarButtonItem = [[UIBarButtonItem alloc] init]; 
[myBarButtonItem addTarget:self action:@selector(myBarButtonItemPressed) forControlEvents:UIControlEventTouchUpInside]; 
myBarButtonItem.title = @"back"; // or whatever text you want 
self.navigationItem.leftBarButtonItem = myBarButtonItem; 
[myBarButtonItem release]; 

- (void)myBarButtonItemPressed 
{ 
    // Do your stuff, like pop view controller 
}