iOS 界面多次present后，dismiss到指定的界面方法

- (void)backAction:(UIButton *)sender{

 

    

    UIViewController *vc =self.presentingViewController;

 //ReadBookController要跳轉的界面

    while (![vc isKindOfClass:[ReadBookController class]]) {

        

          vc = vc.presentingViewController;

    }

    

   [vc dismissViewControllerAnimated:YES completion:nil];

}