ios - view.removeFromSuperview() 很多水龙头的 fatal error

Question

我创建了自己的滑出式导航菜单，但是当我在链接菜单上点击很多时，会导致错误:

fatal error: unexpectedly found nil while unwrapping an Optional value

在滑动面板动画上:

func animateLeftPanel(shouldExpand shouldExpand: Bool) {
    if (shouldExpand) {
        currentState = .LeftPanelExpanded

        animateCenterPanelXPosition(targetPosition: CGRectGetWidth(centerNavigationController.view.frame) - centerPanelExpandedOffset)
    } else {
        animateCenterPanelXPosition(targetPosition: 0) { finished in
            self.currentState = .BothCollapsed

            self.leftViewController!.view.removeFromSuperview()
            self.leftViewController = nil;
        }
    }
}

在 self.leftViewController!.view.removeFromSuperview() 行，我不明白为什么会出现此错误以及如何解决。

Answer 1

尝试:

func animateLeftPanel(shouldExpand shouldExpand: Bool) {
    if (shouldExpand) {
        currentState = .LeftPanelExpanded

        animateCenterPanelXPosition(targetPosition: CGRectGetWidth(centerNavigationController.view.frame) - centerPanelExpandedOffset)
    } else {
        animateCenterPanelXPosition(targetPosition: 0) { finished in
            self.currentState = .BothCollapsed

            if let view = self.leftViewController!.view {
                view.removeFromSuperview()
                self.leftViewController = nil
            }
        }
    }
}

还要检查您的动画 block ，请记住您也可以在动画之前执行此操作以防止在动画期间点击:

self.leftViewController.view.userInteractionEnabled = false

在动画完成 block 中:

self.leftViewController.view.userInteractionEnabled = true

如果你使用一个不在 leftViewController.view 中的按钮来扩展，同样的事情:你可以在动画之前禁用它并在动画完成 block 中重新启用它