1:了解，当创建一个UINavigationcontroller中时，当创建一个子视图控制器压入uiNavigationController中，其中里面的view也别加入UINavigationcontoller.view中去了
验证代码
-(void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
[self digui:self.navigationController.view];
NSLog(@"2.1-->%p",self.view.superview);
}
-(void)digui:(UIView *)view{
for (UIView *child in view.subviews) {
NSLog(@"---%p",child);
[self digui:child];
}
}转场动画第一种方式
-(void)click{
MyViewController *my=[[MyViewController alloc] init];
[self.navigationController pushViewController:my animated:NO];
//因为一个事件循环机制中
CATransition *tran=[CATransition animation];
tran.duration=0.75;
tran.type=@"cameraIrisHollowOpen";
tran.subtype=kCATransitionFromLeft;
[self.navigationController.view.layer addAnimation:tran forKey:nil];
}转场动画第二种方式
-(void)click{
[UIView transitionWithView:self.navigationController.view duration:0.5 options:UIViewAnimationOptionTransitionCurlUp animations:^{
MyViewController *my=[[MyViewController alloc] init];
[self.navigationController pushViewController:my animated:NO];
} completion:^(BOOL finished) {
}];
}转场动画第三种方式
-(void)click{
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.5];
[UIView setAnimationTransition:UIViewAnimationTransitionCurlUp forView:self.navigationController.view cache:YES];
MyViewController *my=[[MyViewController alloc] init];
[self.navigationController pushViewController:my animated:NO];
[UIView commitAnimations];
}