UIViewController *rootController = [self.keyWindowrootViewController];    [rootController presentViewController:self.photoNavigationControlleranimated:YEScompletion:nil];

UIViewController *vc = [[UIViewControlleralloc] init];    vc.view.hidden = YES; // 在回来之后上面会覆盖一层view所以要设为hidden, 否则界面无法操作    [self.keyWindowaddSubview:vc.view];    [vc presentViewController:self.photoNavigationControlleranimated:YEScompletion:nil];