// 拦截返回按钮事件
if ([self.navigationController.viewControllers indexOfObject:self] == NSNotFound) {
ZFLOG(@"clicked navigationbar back button");
[self.tabBarController.tabBar setHidden:NO];
}
// 拦截返回按钮事件
if ([self.navigationController.viewControllers indexOfObject:self] == NSNotFound) {
ZFLOG(@"clicked navigationbar back button");
[self.tabBarController.tabBar setHidden:NO];
}