相关疑难解决方法(0)

我有一个iOS 7应用程序,我在这里设置一个自定义后退按钮,如下所示:

    UIImage *backButtonImage = [UIImage imageNamed:@"back-button"];
    UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];

    [backButton setImage:backButtonImage forState:UIControlStateNormal];
    backButton.frame = CGRectMake(0, 0, 20, 20);

    [backButton addTarget:self
                   action:@selector(popViewController)
         forControlEvents:UIControlEventTouchUpInside];

    UIBarButtonItem *backBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
    viewController.navigationItem.leftBarButtonItem = backBarButtonItem;

但是这会禁用iOS 7"从左向右滑动"手势以导航到之前的控制器.有谁知道如何设置自定义按钮并仍然启用此手势？

编辑:我试图设置viewController.navigationItem.backBarButtonItem,但这似乎并没有显示我的自定义图像.