ios7禁止默认划动返回

 self.navigationController.interactivePopGestureRecognizer.enabled = NO;

或

在使用之前先要判断是否ios7，不然会导致crash。然后创建一个自己的navigationController继承UINavigationController。之后还要设置UINavigationControllerDelegate，这样以上的方法才能触发。最后就判断要show出来的viewController是否需要支持划动返回了。

 - (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated

{

    if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {

        if (viewController.class == [MyViewController class])

        {

            self.interactivePopGestureRecognizer.enabled = NO;

        } else {

            self.interactivePopGestureRecognizer.enabled = YES;

        }

    }

}