AnimatedBuilder should be renamed

The class AnimatedBuilder should have its name replaced. As it is not related to animation in reality.

For example, the following is possible :

final valueNotifier = ValueNotifier(0);

AnimatedBuilder(
  animation: valueNotifier,
  builder: (context, _) {
    return Text(valueNotifier.value.toString());
  },
)

Same goes for ScrollController, ...

I suggest to rename it to ListenableBuilder as it makes more sense.

@Hixie

@Hixie

We can raise the same question about AnimatedWidget. Ultimately it faces the same problem.
Although AnimatedWidget is more honest about its behavior. As AnimatedWidget has its parameter named listenable. While AnimatedBuilder named it animation instead.

These names would be fine if the parameter had for type Animation<T> instead of Listenable.

Maybe an alternative is to keep AnimatedBuilder/Widget but with the type Animation<T>. And change the builder to

Widget animationBuilder(BuildContext context, Widget chid, T value);

And then offer a ListenableBuilder/Widget as a replacement to the current API.

AnimatedWidget used to take an Animation, we changed it to a Listenable much later in its life (when it was first invented, Listenable didn't exist).

Changing this would be a very breaking change, it's probably too late to really make changes here. But it's something we can study when we look at the animation API updates we've discussed.

A bit off topic but where can I find that "animation API update discussion"?

Is ~~#19637~~ #19729 related?

I'm assuming you linked the wrong PR and are probably referring to #19729. I originally wanted to extract some base class out of the AnimatedBuilder but I think there's something inconvenient in the existing API (where the listable wasn't passed back into the builder closure signature). Since a ValueListenableBuilder is as much an encapsulation mechanism as a triggering mechanism, it would be inappropriate for its owner to pass the listenable back into the builder function instead of being self sufficient.

TL;DR, we're unlikely to rename the AnimatedBuilder and you can consider using the ValueListenableBuilder once the PR is merged.

That's already a pretty good start, nice !

In the continuation of this PR, would it be valid if I contributed with an ListenableBuilder and ScrollControllerBuilder ?

Back on the topic, can't we create an AnimationBuilder and mark AnimatedBuilder as @deprecated with other the new builders listed as alternatives ?

AnimationBuilder would be fine as name considering it would listen Animation. Afterall we don't have a StreamedBuilder but SteamBuilder.

Ha, we actually made one too
#18136 (for scrolling), though we didn't check it in because we weren't sure if people would use it.

Regarding the existing API, like Hixie said, we're unfortunately unlikely to change it.

Regarding the scroll builder, I was thinking of listening ScrollController instead of notifications.

I used this pattern a lot for things like parallax or when I need to align an overlay next to a scroll item. Which wouldn't be possible with notifications.

It would also make it more user friendly then notifications I guess

I would recommend making packages for these.

Does #19729 solve this?

IMHO we should discuss what possibilities we have here. It's really difficult for beginners to understand that an animation just triggers Listenables and therefore the AnimationBuilder can be used with any Listenable

Please Flutter team, by any means I can't swallow this, it keeps annoying me all the time cause it sounds horribly wrong.
Stream => StreamBuilder
ValueListenable => ValueListenableBuilder
Listenable => AnimatedBuilder

Well, whether or not you guys decide to rename this Class or not, I learned something today 👍

Now I don't need to populate my initState and setState with tons of ScrollController offsets/etc and simply delegate that to AnimatedBuilder for each of my Widgets that need them.

IMO the real confusion is around the member name animation which implies you need an instance of AnimationController and not any controller -- perhaps this is what needs to be changed or made more "generic".

In any case thanks for teaching me something, I feel this a level up in terms of mastering Flutter and should be required reading 💯

@deprecated

Curious why we wouldn't slap an @deprecated on the AnimatedBuilder and replace with ListenableBuilder? After a cpl yrs, pull it out?

While at it, a "plural" version of this would be quite nice as well. Sometimes you have multiple listenables, changing any of them requires a rebuild, nice not to have to nest builders at the same pt in the tree.

While at it, a "plural" version of this would be quite nice as well. Sometimes you have multiple listenables, changing any of them requires a rebuild, nice not to have to nest builders at the same pt in the tree.

Try passing them to Listenable.merge(), and use this listenable in an AnimatedBuilder.

And it would be great if the team accepts your suggestions about slowly moving to ListenableBuilder.

Yeah, I think this is totally doable now. We could simply introduce this:

@Deprecated('Use ListenableBuilder and bla bla bla ')
typedef AnimatedBuilder = ListenableBuilder;

And then we remove it completely in a later stable version.

I don't think it's much of a hassle...

There is a new PR (#97256) to try to solve this issue

Just to kick the tires on this a bit, #95967 (comment)

Actually, I'm a bit unsure if we want to create an alias for an existing API (AnimatedBuilder), just for the sake of it being more discoverable. This might confuse API users as well - why are there two classes doing the same thing?

It would not primarily be to make it more discoverable (though that is a side-benefit), it would be so we can write proper semantic code that reads correctly and does not mis-lead the reader. Using something called AnimatedBuilder when no Animation is in play, is just plain confusing.

From a comment above

It's really difficult for beginners to understand that an animation just triggers Listenables and therefore the AnimationBuilder can be used with any Listenable

The duplicated functionality would not really be confusing if AnimatedBuilder is deprecated, and eventually removed after a few yrs.

We have just started using something like this to make semantics more clear:

class ListenableBuilder extends AnimatedBuilder {
  const ListenableBuilder({
    Key? key,
    required Listenable listenable,
    required TransitionBuilder builder,
    Widget? child,
  }) : super(key: key, animation: listenable, builder: builder, child: child);
}

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AnimatedBuilder should be renamed #19255

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AnimatedBuilder should be renamed #19255

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zoechi commented on Jul 11, 2018

rrousselGit commented on Jul 11, 2018

Hixie commented on Jul 12, 2018

rrousselGit commented on Jul 13, 2018

zoechi commented on Jul 25, 2018

xster commented on Jul 27, 2018

rrousselGit commented on Jul 28, 2018

xster commented on Jul 28, 2018

rrousselGit commented on Jul 28, 2018

Hixie commented on Jul 28, 2018

zoechi commented on Aug 21, 2018

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