IOS弹出对话框让用户等待

今天看《iPhone开发秘籍》，有段代码非常优雅的完成了这个功能，如下：

 -(void)performDismiss
 {
 [baseAlertdismissWithClickedButtonIndex:0animated:NO];
 }

 -(void)action:(UIBarButtonItem*)item
 {
 baseAlert=[[[UIAlertViewalloc]initWithTitle:@"PleaseWait"message:nildelegate:selfcancelButtonTitle:nilotherButtonTitles:nil]autorelease];
 [baseAlertshow];

 //Createandaddtheactivityindicator
 UIActivityIndicatorView*aiv=[[UIActivityIndicatorViewalloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
 aiv.center=CGPointMake(baseAlert.bounds.size.width/2.0f,baseAlert.bounds.size.height-40.0f);
 [aivstartAnimating];
 [baseAlertaddSubview:aiv];
 [aivrelease];

 //Autodismissafter3seconds
 [selfperformSelector:@selector(performDismiss)withObject:nilafterDelay:3.0f];
 }

首先，显示一个无按钮的alertView，然后添加一个UIActivityIndicatorView作为alertView的子视图

最后，通过alertView的dismissWithClickedButtonIndex:animated:取消显示alertView。

代码和显示效果都非常优雅

其中，UIActivityIndicatorView就是代替了我之前代码中gif图片的作用。

转自http://blog.csdn.net/xianpengliu/article/details/6591592