IssueTracker

Project: platform/frameworks/support
Branch: androidx-main
Author: Louis Pullen-Freilich <lpf@google.com>
Link:      https://android-review.googlesource.com/3328184

Adds OverscrollEffect#withoutDrawing and OverscrollEffect#withoutEventHandling

Adds OverscrollEffect#withoutDrawing and OverscrollEffect#withoutEventHandling 
 
These APIs allow overscroll to have events dispatched to it by one component, and rendered in a separate component. 
 
Fixes: b/266550551 
Fixes: b/204650733 
Fixes: b/255554340 
Fixes: b/229537244 
Test: OverscrollTest 
Relnote: "Adds OverscrollEffect#withoutDrawing and OverscrollEffect#withoutEventHandling APIs - these APIs create a wrapped instance of the provided overscroll effect that doesn't draw / handle events respectively, which allows for rendering  overscroll in a separate component from the component that is dispatching events. For example, disabling drawing the overscroll inside a lazy list, and then drawing the overscroll separately on top / elsewhere." 
Change-Id: Idbb3d91546b49c1987a041f959bce4b2b09a9f61

The following release(s) address this bug.It is possible this bug has only been partially addressed:

• androidx.compose.foundation:foundation:1.8.0-alpha06
• androidx.compose.foundation:foundation-android:1.8.0-alpha06
• androidx.compose.foundation:foundation-jvmstubs:1.8.0-alpha06
• androidx.compose.foundation:foundation-linuxx64stubs:1.8.0-alpha06

Nona, Siyamed,

I think what we need for FilledTextField is a bit different - here is the ticket b/152973638.

I pushed back the CL since it was not clear the expected behavior. We need to define the behavior first, or even we may drop maxLines from TextField.

I checked the resources Anastasia pointed.

The following are use cases from the material perspective:

• single line Textfield (scrolls horizontally)
• multi-line and growing TextField (grows as text does not fit)
• multi-line fixed height TextField (scrolls)

I want to add the following to this list:

• multi-line growing TextField until a height is reached

I checked CSS a bunch, however the amount of attributes related to line clamp behavior is a lot. Some related attrbutes are

• whitespace
• line-clamp
• max-lines

As far I understood input(type=text) is single line, and textarea is multi line in html

• text-area has rows and cols attribute where rows match to height in terms of lines

One of concerns I have (applies to Text(maxLines) as well) is providing the maximum0 height in terms of line height can be done using a modifier

• option a: by converting max lines or lines to from sp to dp
• option b: by providing a modifier that does it for API user.

If we were to assume that sp will be converted to dp, we will need to make sure that the line height can be identified before the composition.

Some nites: From the perspective of TextField:

• single line is an important configuration since we also have to inform IME about this
• we can provide a "lines" attribute/modifier with the semantics of the visual height will be that many lines
• I am not sure if "lines=1" would be singleLine semantics
• we can provide a "maxLines" attribute/modifier with the semantics of the visual height will be at most that many lines

comment copied from b/167396627

FYI scrolling behaviour WIP CL https://android-review.googlesource.com/c/platform/frameworks/support/+/1394667. It's planned to be moved into CoreTextField or BaseTextField (I couldn't do it earlier because cursor was not in coretextfield). We discussed it a few syncs ago and I mentioned that one frame lag was not an issue in my prototype CL.

Please let me know if you're adding the scrolling behaviour, or whether I should continue working on my CL. As I don't want us to do the duplicate work :)