模态视图PresentRotation

-(void)btnClick:(UIButton *)btn{

    DetailViewController *dvc = [[DetailViewController alloc]init];

    if (btn.tag == 100) {

        //上下切换:默认切换方式

        dvc.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

    }

    else if (btn.tag == 101){

        //左右翻转切换

        dvc.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;

    }

    else if (btn.tag == 102){

        //渐变切换

        dvc.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;

    }

    else{

        //卷页切换

        dvc.modalTransitionStyle = UIModalTransitionStylePartialCurl;

    }

    [self presentViewController:dvc animated:YES completion:^{

        NSLog(@"切换完成");

    }];

}