Question

我有一个UIPageViewController，它显示两个UIViewControllers并允许用户在两者之间滑动。我实现了一个按钮，允许用户在两者之间手动切换。执行此操作的代码如下：

[self setViewControllers:@[[self.storyboard instantiateViewControllerWithIdentifier:@"PlayersViewController"]] direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:^(BOOL completion){}];

不幸的是，每次按下按钮，我都会收到一个例外情况：

*由于未捕获的异常终止应用＆＃39; NSInvalidArgumentException＆＃39;，原因：＆＃39; * - [__ NSPlaceholderArray initWithObjects：count：]：尝试从对象插入nil对象[ 0]＆＃39;

我从我的自定义类中调用该方法，该类扩展了UIPageViewControllerDelegate。

非常感谢任何帮助！

**编辑：

以下是我的自定义类的相关部分：

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.dataSource = self;
    gvc = [[GamesViewController alloc] init];
    pvc = [[PlayersViewController alloc] init];
    [self setViewControllers:@[[self.storyboard instantiateViewControllerWithIdentifier:@"GamesViewController"]] direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];
}

- (void) slidepage
{
    [self setViewControllers:@[[self.storyboard instantiateViewControllerWithIdentifier:@"PlayersViewController"]] direction:UIPageViewControllerNavigationDirectionReverse animated:NO completion:^(BOOL completion){NSLog(@"hihi");}];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
    if ([viewController isKindOfClass:[GamesViewController class]])
        return nil;

    return [self.storyboard instantiateViewControllerWithIdentifier:@"GamesViewController"];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    if ([viewController isKindOfClass:[PlayersViewController class]])
        return nil;

    return [self.storyboard instantiateViewControllerWithIdentifier:@"PlayersViewController"];
}

Answer 1

似乎

[self.storyboard instantiateViewControllerWithIdentifier:@"PlayersViewController"]

返回nil。这意味着self.storyboard为nil或故事板无法找到给定标识符的视图控制器。

在UIPageViewController中手动切换视图会导致异常

1 个答案: