Scrolling trouble on UIWebView since 2.3.0

[Manduro]

Ionic version:
[x] 2.x / 3.x

I'm submitting a ...
[x] bug report

Current behavior:
Before 2.3.0 (specifically, before 7e9bad5), js scrolling was used on UIWebView, but only for the virtual scroll component.

Since 2.3.0, up to current master, js scrolling is enabled on every scroll view when using UIWebView. This causes a lot of other functionality to malfunction (InfiniteScroll, Pull to refresh, scrollToX(), etc.). This is because they track scroll position using content.getContentDimensions(), which gets its scrollTop from the scroll element. But, when using js scrolling, its scrollTop is always zero, because scrolling is done using a transform.

Expected behavior:
Latest Ionic should behave like 2.2.0 on UIWebView.

Steps to reproduce:
Run Ionic's own InfiniteScroll e2e test in a UIWebView, and you'll see it doesn't work.

Related code:
pre 2.3.0, js scrolling is enabled here in virtual-scroll.ts.

if (this._config.getBoolean('virtualScrollEventAssist')) {
  this._content.enableJsScroll();
}

post 2.3.0, js scrolling is enabled here in content.ts's constructor:

const jsScroll = config.getBoolean('virtualScrollEventAssist');
this._scroll = new ScrollView(_app, _plt, _dom, jsScroll);

This changed in this commit: 7e9bad5

Other information:
Issues caused by this regression:
#11081
#10976
#10966
#10936
#11051
#10889

There are probably more of them out there. Some have been closed but weren't really fixed in 3.0.0.

[manucorporat]

This is the first time it is reported as an UIWebView only issue... it was my fault though

I am working in a good fix for UI right now. What is stoping you to use WKWebView? We have plans to deprecate UI very soon, making WK the default option.

[manucorporat]

@Manduro could try this nightly release?

• ionic-angular@3.0.0-201704061344

[Manduro]

@manucorporat Yeah took me long enough to figure it out as well, but it was working on mobile safari so that's how I found out ;). Thanks for the quick fix. It seems to be working fine again on first sight.

Is it possible that the 300ms tap delay has returned though? (only on UIWebView as well)

I've tried WKWebView around the v2 beta's I think, but I ran into some minor issues. It's on my list to give it another go soon. The most significant was that I couldn't get autofocus to work anymore, which I believe is a known WK limitation. Any other issues I ran into have probably been solved in Ionic by now.

Thank you for your amazing work on Ionic :)

[manucorporat]

@Manduro when did the 300ms click delay regression happen? updating to 3.0?

[Manduro]

@manucorporat Just checked, 3.0 non-nightly has the delay as well. 2.2 didn't, not sure about 2.3.

[rossholdway]

@manucorporat I'm pretty sure I'm seeing the delay also when running the nightly.

[Manduro]

Just noticed there's an issue about this: #10935.

So I'm closing this one 🎉

[manucorporat]

@rossholdway @Manduro I can confirm the delay. I am working a new fix and a new nightly

[manucorporat]

@rossholdway @Manduro
here's the fix: 32094f7

and a new nightly: + ionic-angular@3.0.0-201704061551

can you please try it really quick? thanks!

[Manduro]

@manucorporat Works here, awesome!

[rossholdway]

@manucorporat Looks good here too 👍

[engehabahmed]

Thanks too muck , you saved my day :) <3

[ionitron-bot]

Thanks for the issue! This issue is being locked to prevent comments that are not relevant to the original issue. If this is still an issue with the latest version of Ionic, please create a new issue and ensure the template is fully filled out.