Add onSizeChanged modifier [154108792]

Fixed

Feature Request

Status Update

No update yet.

Description

ch...@google.com

created issue #1

Apr 15, 2020 03:06PM

Currently I'm using Modifier.onPositioned a lot to know the laid out size of a node, but onPositioned is wasteful for this, especially when it's in a scroller.

Ideally I want just a onSizeChanged modifier to know only when the size changes.

Comments

ma...@google.com <ma...@google.com> #2Apr 15, 2020 03:12PM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit c60f33e229e31ab328ef6b59dab63b264954831c
Author: Alexandre Elias <aelias@google.com>
Date: Fri Jul 10 16:23:09 2020

Semantics no-op cleanups

Partly in response to lmr's broad code review, I did a pass of
superficial API/implementation cleanup. The main changes are:

- I changed each Boolean SemanticsProperty where false is equivalent to
not being present to take "Unit" instead. This is conceptually
clearer: it avoids questions like "can I cancel out a semantics from a
merged child by setting it to false?" Because "property = Unit" looks
weird, I also changed the style of these to "property()".

- I moved the Semantics id generator closer to where it's used, in
SemanticsModifierCore. I made it internal and an AtomicInt.
(Note that integer ids are heavily used in the Android
AccessibilityNodeInfo APIs so I can't simply remove them entirely.)

- I deleted dead code. Some examples include SemanticsHintOverrides,
a public API not connected to anything, and SemanticsPropertyKey
merge() open method which is never called. (In both cases I have
a different plan in mind for accessibility.)

Fixes: 145951226
Fixes: 145955412
Test: existing tests
Relnote: "Single-value semantics properties now use a calling style.
For example, 'semantics { hidden = true }' is now written as:
'semantics { hidden() }'."

Change-Id: Ic1afd12ea22c926babc9662f1804d80b33aa0cfc

M ui/integration-tests/benchmark/src/androidTest/java/androidx/ui/benchmark/test/LayoutNodeModifierBenchmark.kt
M ui/ui-core/api/0.1.0-dev15.txt
M ui/ui-core/api/current.txt
M ui/ui-core/api/public_plus_experimental_0.1.0-dev15.txt
M ui/ui-core/api/public_plus_experimental_current.txt
M ui/ui-core/api/restricted_0.1.0-dev15.txt
M ui/ui-core/api/restricted_current.txt
M ui/ui-core/src/androidAndroidTest/kotlin/androidx/ui/graphics/vector/VectorTest.kt
M ui/ui-core/src/androidAndroidTest/kotlin/androidx/ui/semantics/SemanticsTests.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidActuals.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidComposeView.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidComposeViewAccessibilityDelegateCompat.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidPopup.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/Expect.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsConfiguration.kt
D ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsHintOverrides.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsModifier.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsNode.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsOwner.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsWrapper.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/semantics/SemanticsProperties.kt
M ui/ui-foundation/api/0.1.0-dev15.txt
M ui/ui-foundation/api/current.txt
M ui/ui-foundation/api/public_plus_experimental_0.1.0-dev15.txt
M ui/ui-foundation/api/public_plus_experimental_current.txt
M ui/ui-foundation/api/restricted_0.1.0-dev15.txt
M ui/ui-foundation/api/restricted_current.txt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Clickable.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Dialog.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Scroller.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Selectable.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Toggleable.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/semantics/FoundationSemanticsProperties.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/ButtonTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/CardTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/CheckboxScreenshotTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/RadioButtonScreenshotTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/ScaffoldTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/SnackbarTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/SurfaceTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/ripple/RippleIndicationTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/textfield/TextFieldScreenshotTest.kt
M ui/ui-material/src/main/java/androidx/ui/material/AppBar.kt
M ui/ui-material/src/main/java/androidx/ui/material/TextFieldImpl.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/AssertsTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/CallSemanticsActionTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/ErrorMessagesTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/FindersTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/PrintToStringTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/ScrollToTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/TextActionsTest.kt
M ui/ui-test/src/main/java/androidx/ui/test/Actions.kt
M ui/ui-test/src/main/java/androidx/ui/test/Filters.kt
M ui/ui-text/api/0.1.0-dev15.txt
M ui/ui-text/api/current.txt
M ui/ui-text/api/public_plus_experimental_0.1.0-dev15.txt
M ui/ui-text/api/public_plus_experimental_current.txt
M ui/ui-text/api/restricted_0.1.0-dev15.txt
M ui/ui-text/api/restricted_current.txt
M ui/ui-text/src/commonMain/kotlin/androidx/ui/text/CoreTextField.kt
M ui/ui-text/src/commonMain/kotlin/androidx/ui/text/TextSemanticsProperties.kt

https://android-review.googlesource.com/1360099

ch...@google.com <ch...@google.com> #3Apr 15, 2020 03:17PM

Sorry, the scroller thing was just an example of when a onPositioned would be call a lot without the size changing.

In this case, how do you expect onSizeChanged modifier behave differently from onPositioned other than performance?

I imagine it would act similarly, but only for the size, and not position.

ma...@google.com <ma...@google.com> #4Apr 15, 2020 03:24PM

Reassigned to mo...@google.com.

Oh, I see, thanks for explaining.

I imagine notification only about size change can have some performance wins against position + size notification..

Cc-ing Andrey and reassigning to George, they both have some insights I'm sure. It would be handy to have `Modifier.onSizeChanged`, especially it it will be faster

mo...@google.com <mo...@google.com> #5Apr 15, 2020 06:01PM

Reassigned to ch...@google.com.

You can do this yourself with this:

fun Modifier.onSizeChanged(block: (size: IntPxSize) -> Unit): Modifier = object : LayoutModifier2 {
   private var previousSize: IntPxSize = PxSize.Zero

   override Density.modifySize(
     constraints: Constraints,
     layoutDirection: LayoutDirection,
     childSize: IntPxSize
   ) {
     if (childSize != previousSize) {
       previousSize = childSize
       block(childSize)
     }
     return childSize
   }
}

Would you like something that only cares about the content size or is this what you would like added to the library?

ch...@google.com <ch...@google.com> #6Apr 16, 2020 08:09AM

Reassigned to mo...@google.com.

Yep, that's exactly what I'd like in the library.

I can also see the benefit of having another modifier to know the content size within the parent too.

ch...@google.com <ch...@google.com> #7Apr 16, 2020 12:44PM

Just tried the code above but modifySize doesn't seem to be in LayoutModifier2 (it is in the deprecated LayoutModifier though)

mo...@google.com <mo...@google.com> Jul 13, 2020 09:47PM

Accepted by mo...@google.com.

mo...@google.com <mo...@google.com> #8Sep 1, 2020 11:12PM

Chris, I'd like to make a sample for using OnSizeChanged. Can you give me a short example of how it would be used?

ch...@google.com <ch...@google.com> #9Sep 14, 2020 10:19AM

Here's an example: https://github.com/chrisbanes/tivi/blob/cb/discover-compose/ui-discover/src/main/java/app/tivi/home/discover/Discover.kt#L243

Basically I need to know the height of the app bar, to be able to push down content (y-axis) to be visually below.

Message last modified on Sep 14, 2020 10:20AM

mo...@google.com <mo...@google.com> #10Sep 21, 2020 10:05PM

Nice! I've put in a simplified version of that.

ap...@google.com <ap...@google.com> #11Sep 22, 2020 10:05PM

Marked as fixed.

Project: platform/frameworks/support
Branch: androidx-master-dev

commit 9209f5d65524cf83c0860459955bd83c5615a817
Author: George Mount <mount@google.com>
Date: Tue Sep 01 14:55:57 2020

Add onSizeChanged() and OnRemeasuredModifier

Added a new modifier to make it faster to notify only when a
layout's content size changes. This avoids the down-hierarchy
notifications required when using onPositioned.

Relnote: "Added OnRemeasuredModifier and onSizeChanged() to
receive a callback when content layout has been remeasured and
the size has changed, respectively."

Fixes: 154108792
Bug: 162351735

Test: OnSizeChangedTest
Change-Id: I657cf033de811e9279a2b2079933ca0bd89e5e60

M compose/ui/ui/api/current.txt
M compose/ui/ui/api/public_plus_experimental_current.txt
M compose/ui/ui/api/restricted_current.txt
A compose/ui/ui/samples/src/main/java/androidx/compose/ui/samples/OnSizeChangedSamples.kt
M compose/ui/ui/src/androidAndroidTest/kotlin/androidx/compose/ui/input/pointer/PointerInputEventProcessorTest.kt
A compose/ui/ui/src/androidAndroidTest/kotlin/androidx/compose/ui/layout/OnSizeChangedTest.kt
M compose/ui/ui/src/androidMain/kotlin/androidx/compose/ui/platform/AndroidComposeView.kt
A compose/ui/ui/src/commonMain/kotlin/androidx/compose/ui/OnRemeasuredModifier.kt
M compose/ui/ui/src/commonMain/kotlin/androidx/compose/ui/node/LayoutNode.kt

https://android-review.googlesource.com/1418715