interactivePopGestureRecognizer

1. [_currentNav pushViewController:viewController animated:YES];  
2. //开启iOS7的滑动返回效果  
3. if ([_currentNav respondsToSelector:@selector(interactivePopGestureRecognizer)]) {  
4.     _currentNav.interactivePopGestureRecognizer.delegate = nil;  
5. }