看视频做了demo,通讯都正常了，但是返回键失灵了，怎么回事。

你好，用[self.navigationController pushViewController:chatController animated:YES];

ChatViewController *chatVC = [[ChatViewController alloc] initWithChatter:self.mobile isGroup:NO];
chatVC.title = self.mobile;

UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:chatVC];
//[self presentViewController:nav animated:YES completion:nil];
[self.navigationController pushViewController:chatVC animated:YES];
 
这样就没法跳过去了。是不是AppDelegate.m里面要做什么初始化？

请参考我们的ios UI继承视频http://v.youku.com/v_show/id_XMTMwMDQ5MDA0NA==.html?f=23630826&from=y1.2-3.4.4