iOS如何让主界面不显示NavigationBar

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    [self.navigationController setNavigationBarHidden:YES animated:animated];
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];

    [self.navigationController setNavigationBarHidden:NO animated:animated];
}

注意，animated设为YES，仍是会有一个瞬间的过渡效果。只有设置为animated才能真正实现。