Activity 指示器未显示在视图控制器上

Question

我想弄清楚为什么我的 activity 指示器没有显示在我的视图控制器上，下面是我的代码

var activityIN : UIActivityIndicatorView = UIActivityIndicatorView(frame: CGRectMake(0,0, 50, 50)) as UIActivityIndicatorView
        activityIN.center = self.view.center
        activityIN.hidesWhenStopped = true
        activityIN.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
        activityIN.startAnimating()

Answer 1

试试这个，看到最后一行你忘记了

var activityIN : UIActivityIndicatorView = UIActivityIndicatorView(frame: CGRectMake(100 ,200, 50, 50)) as UIActivityIndicatorView
activityIN.center = self.view.center
activityIN.hidesWhenStopped = true
activityIN.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
activityIN.startAnimating()
self.view.addSubview(activityIN)

Activity 指示器未显示在视图控制器上

Activity Indicator not showing on view controller

swift

uiactivityindicatorview