for (UIView * thebtn in [self.view subviews]) {         if ([thebtn isKindOfClass:[UIButton class]])         {     //***改变字体颜色                            [(UIButton *)thebtn setTitleColor:[UIColor redColor]     forState:UIControlStateNormal];             //***改变背景                         [(UIButton *)thebtn setBackgroundImage:nil forState:UIControlStateNormal];                    }               }