兩種方法:
一:[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:([self.navigationController.viewControllers count] -x)] animated:YES];
這樣就可以獲得你想pop回去的ViewController的指標了，只要改變一下“x”這個數字就行了，嘗試一下。。

二:XXView *rootViewController = nil;
for (UIViewController *VC in self.navigationController.viewControllers) {
    if ([VC isKindOfClass:[XXView class]]) {
        rootViewController = (XXView *)VC;
    }
}
[self.navigationController popToViewController:rootViewController animated:YES];