在UISplitViewController中,无法使showDetailViewController:sender:push into detail navigationController

Question

在iOS 8中,视图控制器现在可以调用showDetailViewController:sender:以让系统确定正确的视图控制器以呈现详细视图控制器.

在我的应用程序中,我有一个UISplitViewController,它的viewControllers数组中包含两个UINavigationControllers.第一个UINavigationController包含我的"主"视图,UITableViewController的子类.第二个UINavigationController包含我的"详细信息"视图.

因为我试图使这项工作普遍,我试图showDetailViewController:sender:用来显示详细信息视图:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

    self.itemVC.item = self.itemStore.items[indexPath.row];

    [self showDetailViewController:self.itemVC sender:self];
}

这适用于水平紧凑特性(iPhone风格)时self.splitViewController.collapsed == YES,但不适用于特性为常规(iPad,未折叠)时.在iPad上,它用细节视图控制器替换细节UINavigationController(而不是替换UINavigationController的viewControllers数组).

为了解决这个问题,我已经测试了它是否已经崩溃,如果不是,我会在显示它之前将详细视图控制器包装在另一个UINavigationController中:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

    self.itemVC.item = self.itemStore.items[indexPath.row];

    UIViewController *vcToShow;

    // For whatever reason, when not collapsed, showDetailViewController replaces the detail view, doesn't push onto it.
    if (self.splitViewController.collapsed) {
        vcToShow = self.itemVC;
    } else {
        vcToShow = [[UINavigationController alloc] initWithRootViewController:self.itemVC];
    }

    [self showDetailViewController:vcToShow sender:self];
}

我想或者我可以配置self.itemVC并避免showDetailViewController:sender:在self.splitViewController.collapsed == NO以下情况下完全调用:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

    self.itemVC.item = self.itemStore.items[indexPath.row];

    // For whatever reason, when not collapsed, showDetailViewController replaces the detail view, doesn't push onto it.
    if (self.splitViewController.collapsed) {
        [self showDetailViewController:vcToShow sender:self];
    }
}

但是,这感觉就像它破坏了目的showDetailViewController:sender:,即放松self视图层次结构之间的耦合.

有没有更好的方法来处理这个？

Answer 1

在showDetailViewController:sender:视collapse财产,你需要创建要在细节显示控制器.

例如,在横向模式的iPad上,它已经从故事板创建了详细视图控制器,但在iPhone 5上折叠时,视图控制器尚不存在.

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    UINavigationController *detail;
    ImageViewController *imageVC;

   // on the iPhone (compact) the split view controller is collapsed
   // therefore we need to create the navigation controller and its image view controllerfirst
   if (self.splitViewController.collapsed) {
       detail = [[UINavigationController alloc] init];
       imageVC = [self.storyboard instantiateViewControllerWithIdentifier:@"ImageViewController"];
       [detail setViewControllers:@[imageVC] animated: NO];
   }
   // if the split view controller shows the detail view already there is no need to create the controllers
   else {
       id vc = self.splitViewController.viewControllers[1];
       if ([vc isKindOfClass:[UINavigationController class]]) {
           detail = (UINavigationController *)vc;
           imageVC = [detail.viewControllers firstObject];
       }
    }

    [self prepareImageViewController:imageVC forPhoto:self.photos[indexPath.row]];
    // ask the split view controller to show the detail view
    // the controller knows on iPhone and iPad how to show the detail
    [self.splitViewController showDetailViewController:detail sender:self];
}

我希望这能解决你的问题.