ios - 在第三方 API 上调用属性选择器时应用程序崩溃

Question

我正在使用第三方库并在我的代码中调用方法时随机面临崩溃。

崩溃日志说无法识别的选择器 viewControllers 发送到 .

崩溃日志：由于未捕获的异常“NSInvalidArgumentException”而终止应用程序，原因：“-[ThirdPartyController viewControllers]：无法识别的选择器发送到实例 0x1e959bc0”

但是，如果您在下面看到，我在调用此方法之前已经采取了所有安全处理。有什么问题。

+ (UINavigationController *)currentNavigationController:(UINavigationController *)iPreviousNavigationController {
 UINavigationController *aCurrentNavigationController = iPreviousNavigationController;
 UINavigationController *aChildNavigationController = (UINavigationController *)[iPreviousNavigationController modalViewController];

 if (aChildNavigationController) {
aCurrentNavigationController = [self currentNavigationController:aChildNavigationController];
 } 

 return aCurrentNavigationController;

}

+ (UIViewController *)currentViewController:(UINavigationController *)iPreviousNavigationController {
    UINavigationController *aCurrentNavigationController = [self currentNavigationController:iPreviousNavigationController];

    if (!aCurrentNavigationController || ![aCurrentNavigationController respondsToSelector:@selector(viewControllers)]) {
    aCurrentNavigationController = [self applicationDelegate].navigationController;
    }

    UIViewController *aCurrentViewController;

    if ([aCurrentNavigationController respondsToSelector:@selector(viewControllers)]) {
         aCurrentViewController = [aCurrentNavigationController.viewControllers lastObject];
    }

    return aCurrentViewController;
}