Revise Android and iOS gestures on Material TextField - #24457

I'm not sure that "concurrent" is the best way to describe the events this widget recognizes. The next paragraph calls them event chains, maybe: A gesture detector that recognizes all of the individual tap up/down and double tap down events in a chain of events.

Reworded

This widget is unlike a plain [GestureDetector] which only recognizes one tap or double tap in a chain of events.

tweaked it

Key key, and pass the key along via a super call

Ah thanks, I always forget it

Not sure what the difference between "tap was held momentarily" and "a short tap" is.

Reworded this part

I think it would be better to explain when this is called. I assume it's called because a tap down occurred - and onTapDown was called, and the pointer only moved a little and was held down long enough to qualify as a "long tap down".

Also: there's no shame in mentioning kDoubleTapTimeout and kDoubleTapSlop

Added some more details. It's not really related to those 2 constants.

This makes the semantics of this widget rather complicated. Where do we define the semantics of a GestureDetector that's a TextSelectionGestureDetector descendant? Or a TextSelectionGestureDetector that's a TextSelectionGestureDetector descendant? It wasn't necessary to explain this kind of thing when the translucent gesture detector was a TextField implementation detail, but now...

Can you elaborate? I'm not sure I understand. The widget structure should be more or less the same as before.

That's right, it is the same as before. But now this is a public class and so it's necessary to explain its semantics.

What happens when a TextSelectionGestureDetector has a GestureDetector descendant? Similarly what does it mean to have a TextSelectionGestureDetector with a TextSelectionGestureDetector descendant?

Did what you suggested last week. Thanks for the tip!

I think this means: not called if it follows a "tap up" within kDoubleTapTimeout?

We don't necessarily need to be too specific and redefine a double click in word. There's other little things like not being too far from the previous tap etc.

If the double tap timer is running, then upon seeing the second tap down, I think it should always be reset. Otherwise we could recognize an arbitrarily long sequence of taps as a double tap, so long as the intermediate ones were outside kDoubleTapSlop.

if (_doubleTapTimer != null) {
  if (widget.onDoubleTapDown != null && _isWithinDoubleTapTolerance(details.globalPosition)) {
     widget.onDoubleTapDown(details);
  }
  ...
}

Also: this logic seems like it would map a sequence of 4 quick taps to a 3 double taps? Doesn't seem right.

We talked about this offline. Also added test

This isn't wrong but we usually just look up the Theme as needed. InheritedWidget lookups are very cheap. Binding the theme to a final var at the top of a build method is probably the closest conventional way to do this.

Yup, removed this

An ordinary [GestureDetector] configured to handle events like tap and double tap will only recognize one or the other. This widget detects both: first the tap and then, if another tap down occurs within a time limit, the double tap.

Took your wording

can be called for one sequence input gestures.

done

but except touches that are quickly => except touches that include enough movement to not qualify as taps (e.g. ...)

done

Called for each distinct tap except for the second tap down of a double tap. For example, if the detector was configured [onSingleTapDown] and [onDoubleTapDown], three quick taps would be recognized as a single tap down, followed by a double tap down, followed by a single tap down.

[I hope I've gotten that right!]

Mostly took your wording. Tweaked the first sentence.

That's right, it is the same as before. But now this is a public class and so it's necessary to explain its semantics.

What happens when a TextSelectionGestureDetector has a GestureDetector descendant? Similarly what does it mean to have a TextSelectionGestureDetector with a TextSelectionGestureDetector descendant?

I think what you mean is that slow double tap doesn't trigger a word selection.

sure. Changed

Not clear what this tap is for? Aren't we just checking a double tap?

Unfortunately the rebase broke the github comment. I can't figure out which line you commented on anymore

What's the tapAt on line 3695 for? It doesn't seem to be needed for the test.

As before, what's this tap for?

This functions look like one liners that return an int. Maybe:

void _handleTapDown(TapDownDetails details) { tapCount += 1; }

done

It seems odd to say a "gesture detector to detect". Maybe: "A gesture detector that matches non-exclusive ...".

Changed to respond which is a fairly standard word

Need to update this because child is required to be non-null.

Ah, big catch. Thanks!

A comment that explained the significance of 300ms would be helpful (I assume 300ms > double tap interval).

Done

two slow taps do not ...

Thanks

What's the tapAt on line 3695 for? It doesn't seem to be needed for the test.