ios 自定义转场动画的问题_course

我现在在写自定义转场动画 present跳转的动画，遵循了代理但是代理方法不执行，push跳转的同样是自定义没问题，网上看了demo对比了下没发现区别但是就是不行，下面贴代码 @interface ViewController () < UIViewControllerTransitioningDelegate > @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; [self initSubviews]; self.transitioningDelegate = self; } -(void)initSubviews{ self.view.backgroundColor = [UIColor whiteColor]; UIButton * btn = [[UIButton alloc]init]; btn.frame = CGRectMake(100, 100, 50, 50); btn.backgroundColor = [UIColor redColor]; [btn addTarget:self action:@selector(push) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:btn]; } -(void)push{ ViewController3 * vc = [[ViewController3 alloc]init]; [self presentViewController:vc animated:YES completion:nil]; } -(id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed{ return [[obj_Animation alloc]init]; } -(id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source{ return [[obj_Animation alloc]init]; } 求教是什么问题