ios - 呈现另一个 View Controller 将 UITableView 滚动到顶部

Question

I have a PFQueryTableViewController, which is set up to instantiate and present a new view controller, inside of a UINavigationViewController, when a row is selected.

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    if ([self objectAtIndexPath:indexPath]) { // Check our object exists
        MyNewViewController *card = [[MyNewViewController alloc] init];

        UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:card];
        [nav.navigationBar configureFlatNavigationBarWithColor:[UIColor pomegranateColor]];
        [self presentViewController:nav animated:YES completion:^{}];
    }
    else { // Otherwise, do what we would have done.
        [super tableView:tableView didSelectRowAtIndexPath:indexPath];
    }
}

当我选择一行时， TableView 一直滚动(不是动画)到顶部，就在新 View Controller 出现之前。这是第一个问题，因为它使用户很难跟踪他们的位置。

第二个问题是，当我退出新的 View Controller ，返回到 TableView Controller 时，我无法从第一个单元格向下滚动。它反弹，我可以看到一些第二个细胞，但它不会下降。重新加载表格会导致滚动再次起作用。

如何防止滚动回到顶部，为什么滚动到顶部后限制滚动？

Answer 1

尝试这样的事情:

@implementation PFQueryTableViewController
{
    UIViewController* _rootViewController;
    UINavigationController* _nav
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    if ([self objectAtIndexPath:indexPath]) { // Check our object exists
        MyNewViewController *card = [[MyNewViewController alloc] init];

        _nav = [[UINavigationController alloc] initWithRootViewController: card];
        [nav.navigationBar configureFlatNavigationBarWithColor: [UIColor pomegranateColor]];
        AppDelegate* appDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
        _rootViewController = appDelegate.window.rootViewController;

        [UIView transitionFromView: _rootViewController
                            toView: _nav.view
                          duration: 0.5
                           options: UIViewAnimationOptionTransitionFlipFromRight |
         UIViewAnimationOptionAllowUserInteraction    |
         UIViewAnimationOptionBeginFromCurrentState
                        completion: ^(BOOL finished)
         {
             appDelegate.window.rootViewController = nav;
             [appDelegate.window makeKeyAndVisible];
         }];
    }
    else { // Otherwise, do what we would have done.
        [super tableView:tableView didSelectRowAtIndexPath:indexPath];
    }
}

然后你需要从 navcontroller 调用下一个方法返回到表:

- (void) returnToTheQueryTableViewController
{
    [UIView transitionFromView: _nav.view
                        toView: _rootViewController.view
                      duration: 0.5
                       options: UIViewAnimationOptionTransitionFlipFromRight |
     UIViewAnimationOptionAllowUserInteraction    |
     UIViewAnimationOptionBeginFromCurrentState
                    completion: ^(BOOL finished)
     {
         AppDelegate* appDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
         appDelegate.window.rootViewController = _rootViewController;
         [appDelegate.window makeKeyAndVisible];
     }];
}

希望对你有帮助。