ios - UINavigation bar back button in ios 7

Question

i am developing a application which have a activity indicator in UINavigationbar and the problem is that when i hide the activity indicator the default navigation back button not displayed in ios 7 but in ios 6 it works perfectly

i am getting self.navigationItem.backBarButtonItem as nil when i print it in console

after hiding activity indicator i have written below code

[self.navigationItem setLeftBarButtonItem:self.navigationItem.backBarButtonItem];

Thanks in advance

Answer 1

代替：

[self.navigationItem setLeftBarButtonItem:self.navigationItem.backBarButtonItem];

尝试使用：

[self.navigationItem setBackBarButtonItem:self.navigationItem.backBarButtonItem];

（我不确定这是否会完全像这样工作。您可能必须在显示活动指示器之前将后退按钮存储在一个变量中，然后再将后退按钮设置为该变量。）

Answer 2

我是一名初学者，但我的理解是显示的后退按钮实际上是前一个视图控制器的属性，而不是显示的视图控制器的属性。

除非您为当前可见的视图控制器手动设置了后退按钮，否则它应该为零。

尝试从堆栈中的前一个视图控制器记录后退按钮项，这可能会有所帮助