UINavigationController先pop再push

HXChatMsgViewController *chatMessage = [[HXChatMsgViewController alloc]initWithChatter:model.profile.userId isGroup:NO];
NSMutableArray *ViewCtr = [NSMutableArray arrayWithArray:self.navigationController.viewControllers];
NSLog(@"navigation viewControllers is %@", ViewCtr);
int index = (int)[ViewCtr indexOfObject:self];
[ViewCtr removeObjectAtIndex:index];
[ViewCtr addObject:chatMessage];
NSLog(@"the viewCtl is %@", ViewCtr);
[self.navigationController setViewControllers:ViewCtr animated:YES];