iphone - UINavigationBar 中的事件指示器

Question

我已经阅读了一些关于这个特定主题的答案，但由于某种原因，我的代码似乎不起作用。它位于 UISearchBarDelegate 委托(delegate)方法中 -(void)searchBarSearchButtonClicked:(UISearchBar *)searchBar

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

非常感谢任何帮助或建议!

Answer 1

我相信 UIActivityIndi​​catorView 的指定初始化程序是 initWithActivityIndi​​catorStyle:。尝试像这样创建 activityIndi​​cator。

UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];