swift5:

let alertController = UIAlertController(title: "删除该好友",
                                                message: "确认是否删除该好友", preferredStyle: .alert)
        let cancelAction = UIAlertAction(title: "再想想", style: .cancel, handler:{
            action in
            
        })
        
        let okAction = UIAlertAction(title: "确认删除", style: .default, handler: {
            action in
            self.deleteFriend()
        })
        okAction.setValue(UIColor.red, forKey:"titleTextColor")//alertController按钮颜色
        alertController.addAction(cancelAction)
        alertController.addAction(okAction)
        self.present(alertController, animated: true, completion: nil)

UIAlertController *alertController = [[UIAlertController alloc] init];
    
    NSMutableAttributedString *title = [[NSMutableAttributedString alloc] initWithString:@"抵用券选择"];
    [title addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:17] range:NSMakeRange(0,5)];
    [title addAttribute:NSForegroundColorAttributeName value:[UIColor blackColor] range:NSMakeRange(0,5)];
    [alertController setValue:title forKey:@"attributedTitle"];

    if ([[[UIDevice currentDevice]systemVersion]floatValue]>8.3) {
        UIAlertAction*cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
        //修改取消按钮颜色
        [cancelAction setValue:[UIColor redColor] forKey:@"_titleTextColor"];
        [alertController addAction:cancelAction];
        for (L_yh *yh in _model.l_yh) {
            UIAlertAction *action = [UIAlertAction actionWithTitle:yh.name style:UIAlertActionStyleDefault handler:nil];
            //修改按钮颜色、这里如果加了判断
            [action setValue:_kMainColor forKey:@"_titleTextColor"];
            [alertController addAction:action];
        }
    }else {
        UIAlertAction*cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
        [alertController addAction:cancelAction];
        //修改取消按钮颜色

        for (L_yh *yh in _model.l_yh) {
            UIAlertAction *action = [UIAlertAction actionWithTitle:yh.name style:UIAlertActionStyleDefault handler:nil];
            [alertController addAction:action];
        }
        alertController.view.tintColor = _kMainColor;
    }

    [_controll presentViewController:alertController animated:YES completion:nil];

自定义action对的颜色和大小
https://github.com/Friend-LGA/LGAlertView

https://github.com/szk-atmosphere/MSAlertController