为什么在导航栏中未显示uiactivity指示器

Question

UIActivityIndicatorView *activityView = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0, 0, 14, 14)]; 
[activityView sizeToFit]; 
[activityView setAutoresizingMask:(UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin)]; 

activityView.hidesWhenStopped = NO; 

self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:activityView]; 

[activityView startAnimating]; 

uiactivity指示器未显示在右上角的原因是什么？什么都不显示在右上方的导航栏中。

Answer 1

因为你不分配活动指示灯的颜色 指定颜色的话，我会在导航栏中显示

activityView.color = [UIColor blackColor]; 

Answer 2

你需要设置活动的指标类型...试试这个：

UIActivityIndicatorView * activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite]; 
activityView.frame = CGRectMake(0, 0, 14, 14); 
[activityView sizeToFit]; 
[activityView setAutoresizingMask:(UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin)]; 

activityView.hidesWhenStopped = NO; 

self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:activityView]; 

[activityView startAnimating];