根据MBProgressHUD版本不同举例以下两种方法解决：
方法一：
MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:KeyWindow.rootViewController.view animated:YES]; ;
hud.mode = MBProgressHUDModeText;
hud.detailsLabel.font = [UIFont boldSystemFontOfSize:16];
hud.detailsLabel.text= string;
hud.removeFromSuperViewOnHide = YES;
[hud hideAnimated:YES afterDelay:1.5];
方法二：
MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:KeyWindow.rootViewController.view animated:YES]; ;
hud.mode = MBProgressHUDModeText;
hud.detailsLabelText= @"感谢您的反馈，我们已经收到！";
hud.detailsLabelFont = [UIFont boldSystemFontOfSize:16];
hud.removeFromSuperViewOnHide = YES;
[hud hide:YES afterDelay:1.5];
