Other ways of specifying the page to go to

[gazialankus]

When navigating between pages in pageListBuilder, it gets tricky to address which one you want to navigate to. Indices or next/prev is not reliable as they tend to shift over time. showPageWithId is best but you have to give ids to each page. It would be nice to have a convenient way to address which one of the pages you want to navigate to.

Since id is an object, I actually give the type as the id and found that it works very well. For example, when I do this,

class UserDetailViewPage extends SliverWoltModalSheetPage {
  UserDetailViewPage(BuildContext context, User user)
      : super(
    id: UserDetailViewPage,
    mainContentSliversBuilder: (context) =>

I'm able to do this later

WoltModalSheet.of(context).showPageWithId(UserDetailViewPage);

However, if I ever want to use two UserDetailViewPage instances I would have to use another solution.

So what I think we can do is to give a discriminator/selector function that will decide which specific page we should go to. Something like:

// there is a single user detail page to find 
// find it by type
WoltModalSheet.of(context).showPageOfType<UserDetailViewPage>();
// find it with a general selector function
WoltModalSheet.of(context).showPage(with: (p) => p is UserDetailViewPage);

// there can be multiple user detail pages but I want to show the one with selectedUserId
// the general selector function can help
WoltModalSheet.of(context).showPage(with: (p) => p is UserDetailViewPage && p.userId == selectedUserId);
// or maybe better with strong types
WoltModalSheet.of(context).showPage<UserDetailViewPage>(with: (p) => p.userId == selectedUserId);

This way we can specify at the time of navigation which one of those instances we want to navigate to. How does this sound?

[ulusoyca]

@gazialankus this is amazing suggestion. Do you think you can create a PR? It should be straigh-forward. You can also update the example project with your suggestion in this file.

WoltModalSheet.of(context).showPage<UserDetailViewPage>(with: (p) => p.userId == selectedUserId);

We should also handle the case where the the condition is not met for example returning true or false as in

  bool showAtIndex(int index) {
    if (index < _pages.length && index >= 0) {
      _currentPageIndex = index;
      return true;
    }
    return false; // No navigation occurred, already at the last page.
  }

[ulusoyca]

Merged. Thanks for the contribution. Target release: 0.10.0