IOS 修改导航Push动画

1：第一步：编写一个继承NSObject的动画类YLAnimator遵循协议UIViewControllerAnimatedTransitioning

实现委托方法：

- (NSTimeInterval)transitionDuration:(id)transitionContext{ //动画时长

return 1;

}

- (void)animateTransition:(id)transitionContext   {//动画实现

      UIViewController* toViewController = [transitionContext    viewControllerForKey:UITransitionContextToViewControllerKey];

UIViewController* fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];

[[transitionContext containerView] addSubview:toViewController.view];

CGAffineTransform transform = CGAffineTransformIdentity；

//transform的具体实现形式

//eg   tansform = CGAffineTransformTranslate(tansform, <#CGFloat tx#>, <#CGFloat ty#>)

toViewController.view.transform = transform;

[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{

       toViewController.view.transform = CGAffineTransformIdentity;

} completion:^(BOOL finished) {

fromViewController.view.transform = CGAffineTransformIdentity;

[transitionContext completeTransition:![transitionContext transitionWasCancelled]];

}];

}

2.第二步，自定义UINavigationDelegate类 YLNavigationDelegate

实现委托方法UINavigationControllerDelegate

- (id)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC{

    if (operation == UINavigationControllerOperationPush )    {

           return self.animator;  //自定义的动画

     }

}

return nil;

｝

3:第三步，修改自定义的YLNavigationController,一般继承自UINavigationController

-(instancetype)initWithRootViewController:(UIViewController *)rootViewController{

      if(self = [super initWithRootViewController:rootViewController]){

          _navDelegate = [[YLNavigationControllerDelegate alloc] init];   

        self.delegate = _navDelegate;

}

return self

}