Unable to update the ConvexAppBar's index.

[JaisonST]

Hey! love the package it works great. I was trying to automatically move the index along with page swipes. I have a setState() that is updating a global index value. I'm unable to access currentIndex or some kind of active index that would auto update the navbar.

Here's my code:

  final _pageViewController = PageController();
  int _activePage = 0;

@override
  void dispose() {
    _pageViewController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: PageView(
        controller: _pageViewController,
        children: <Widget>[
          Container(color: Colors.red),
          Container(color: Colors.green),
          Container(color: Colors.blue)
        ],
        onPageChanged: (index) {
          setState(() {
            _activePage = index;
          });
        },
      ),
      bottomNavigationBar: ConvexAppBar(
        items: [
          TabItem(icon: Icons.message, title: 'Chat'),
          TabItem(icon: Icons.home, title: 'Home'),
          TabItem(icon: Icons.people, title: 'Profile'),
        ],
        onTap: (int i) {
          _pageViewController.animateToPage(i,
              duration: Duration(milliseconds: 200), curve: Curves.bounceOut);
        },
        backgroundColor: Colors.black,
        initialActiveIndex: _activePage,
      ),
    );
  }

as u can see, i've swiped to Profile screen but its still on chat in the ConvexAppBar.

[mt-akar]

This is because the widget includes an initialActiveIndex property instead of the standard selectedIndex property.

My project requires has the same situation. It requires to go back to the previous page when the back button is pressed, which in turn requires a selectedIndex property to be present.

This is a common behavior pattern and exists in both flutter's own BottomNavigationBar and in almost all other packages. It should be included here as well.

[JaisonST]

@m-azyoksul, Yea maybe most packages don't have an active index, however i was able to build the functionality i was looking for without the ConvexAppBar package using a BottomNavigationBar's property of currentIndex. Couldn't recreate the Animation that ConvexAppBar provided tho. Fingers Crossed there'd be an update with access to currentIndex.

[mt-akar]

@JaisonST What I mean by selectedIndex is exactly the same as BottomNavigationBar's currentIndex.

There are a bunch of packages that do have a currentIndex property besides the framework one such as flutter_snake_navigationbar, salomon_bottom_bar, water_drop_nav_bar, sliding_clipped_nav_bar, persistent_bottom_nav_bar, bottom_bar, etc. You might like the design of one of these packages. bottom_bar package even explains how to make the swipeable-page layout as you want it.

I still think this package should also implement the currentIndex property.

[avenwu]

will take into consideration

[dishankjindal1]

I am having a same issue. I am trying to rebuild the bottom nav bar.

In my Scenario, I have 2 Tab Items if auth is false otherwise 3 Tab Items if auth is true.

what is happening in my case, i am forcing the parent of the convex bottom bar to restart with the fresh data.
It updates the tab correctly but the alignment of the active items initally is as per the previous state but after i tap on the items everything is fixed.

Screenshot1	Screenshot2
As you can see, my app is initially designed to have 2 tabs, But when it see an admin user, I added a new tab to the screen	now when I press on any tab the issue fixes itself, but it happening on every cold start

[povpros]

check this
https://github.com/hacktons/convex_bottom_bar/blob/master/doc/issue-change-active-tab-index.md

[vytautas-pranskunas-]

wow.. cannot believe this package lacks such simple thing.... Instead suggesting

_appBarKey.currentState.animateTo(2/* index*/);

it would so much cleaner to implement currentIndex because for example now I am changing select index from MobX store and have to do hacks (in order not to break single responsibility) to listen to index change and animate to tab.... This is really not right way...