弹出框的运用

介绍弹出框的用法 - (IBAction)btn:(id)sender { PoPoverViewController * popover = [[[PoPoverViewController alloc]initWithNibName:@"PoPoverViewController" bundle:nil] autorelease]; popover.mainViewController = self; UIPopoverController * pcr = [[[UIPopoverController alloc] initWithContentViewCont