ios - UIPageViewController 有条件地转到下一页

Question

我有 UIPageViewController，我可以使用以下委托(delegate)方法转到下一页和上一页。

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

    if(_counter < 1) {
       return nil;
    }

    self.view.backgroundColor = [UIColor lightGrayColor];
    return [self.storyboard instantiateViewControllerWithIdentifier:@"memoTable"];
}

编辑:

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    //NSLog(@"Child controller count  = %lu",(unsigned long)pageViewController.childViewControllers.count);

    if ([viewController isKindOfClass:[PageController class]])
        return nil;

    if([viewController isKindOfClass:[TableViewController class]])
    {
        TableViewController *viewController1 = (TableViewController*) viewController;
        if (viewController1.dataArr.count < 5) {
            return nil;
        }
    }

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

如果满足某些条件，现在我想转到下一页。就像上一页一样viewController.isCheck == true。

我怎样才能做到这一点？

Answer 1

您可以将该条件添加到现有 ifs 之一，如果条件未验证则返回 nil。像这样的东西:

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    if ([viewController isKindOfClass:[PageController class]] || ((YourViewControllerClass *)viewController).isCheck == false)
       return nil;

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