如何向Navbar添加活动指标？

Question

嘿，当我的用户更改Picker Wheel选择时，我想在Navbar的右角显示活动指示器。我不知道如何添加活动指示器，我只能在那里添加普通的Navbar按钮。有帮助吗？提前致谢！

Answer 1

UIActivityIndicatorView *activityIndicator =  
[[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0, 0, 20, 20)];  
UIBarButtonItem *barButton = [[UIBarButtonItem alloc] 
                                         initWithCustomView:activityIndicator];  
[[self navigationItem] setRightBarButtonItem:barButton];  

[barButton release];  
[activityIndicator startAnimating];  

这应该起作用。从： http://iosdevelopertips.com/user-interface/adding-an-activity-indicator-spinner-pinner-spinner-to-navigation-bar.html