[C, iOS, Android] LayoutCompression #1136

StephaneDelcroix · 2017-09-12T08:45:46Z

Description of Change

Enable Layout Compression for iOS and Android.

NOTE: this feature is still in beta, and opt-in only

Layout Compression allows the user to avoid creating renderers for Layouts (i.e. StackLayout, ContentView, ...).

Pros:

less renderers to create, manage and dispose
less UI elements on screen

Cons:

compressed layouts can't have BG colors, gesture recognizers
no transformation
...

Sample:

<?xml version="1.0" encoding="UTF-8"?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
	xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
	x:Class="Xamarin.Forms.Controls.CompressedLayout"
	Padding="0,20,0,0">
	<StackLayout Padding="6" CompressedLayout.IsHeadless="true">
		<Label Text="First"/>
		<StackLayout Padding="6" CompressedLayout.IsHeadless="true">
			<Label Text="Second"/>
			<ContentView Padding="6" CompressedLayout.IsHeadless="true" BackgroundColor="Pink" >
				<Label x:Name="this" Text="Third"/>
			</ContentView>
			<Label Text="Fourth"/>
		</StackLayout>
		<Label Text="Fifth"/>
	</StackLayout>
</ContentPage>

Enabling LayoutCompression for this layout only creates a Renderer for the page, and one for each label. The BackgroundColor property on the inner ContentView is ignored.

Bugs Fixed

/

API Changes

Added:

public static readonly BindableProperty CompressedLayout.IsHeadlessProperty;

Behavioral Changes

/

PR Checklist

Has tests (if omitted, state reason in description)
Rebased on top of master at time of PR
Changes adhere to coding standard
Consolidate commits as makes sense

hartez · 2017-09-12T20:13:34Z

Xamarin.Forms.Platform.Android/Renderers/LocalizedDigitsKeyListener.cs

@@ -34,7 +34,9 @@ public static NumberKeyListener Create(InputTypes inputTypes)
 			if ((inputTypes & InputTypes.NumberFlagDecimal) == 0)
 			{
 				// If decimal isn't allowed, we can just use the Android version
+#pragma warning disable 0618 // Find issues with Android API usage


Which part of the next line is giving an obsolete warning?

On X.A 7.5.0.15 (Alpha channel at this time): 'DigitsKeyListener.GetInstance(bool, bool)' is obsolete

[Register ("getInstance", "(ZZ)Landroid/text/method/DigitsKeyListener;", ""), Obsolete ("deprecated")] public unsafe static DigitsKeyListener GetInstance (bool sign, bool @decimal);

fixed in master

hartez · 2017-09-12T20:14:12Z

Xamarin.Forms.Platform.Android/VisualElementPackager.cs

-		public VisualElementPackager(IVisualElementRenderer renderer)
+		VisualElement _element;
+
+		IElementController ElementController => _element;// _renderer.Element as IElementController;


Can probably remove this comment.

hartez · 2017-09-12T20:17:54Z

Xamarin.Forms.Platform.iOS/RendererPool.cs

+					if (CompressedLayout.GetIsHeadless(child)) {
+						child.IsPlatformEnabled = true;
+						FillChildrenWithRenderers(child);
+					} else {


Missing a tab on the next line.

hartez · 2017-09-12T20:18:32Z

Xamarin.Forms.Platform.iOS/VisualElementPackager.cs

@@ -13,16 +13,20 @@ public class VisualElementPackager : IDisposable

 		bool _isDisposed;

-		IElementController ElementController => Renderer.Element as IElementController;
+		IElementController ElementController => _element;// Renderer.Element as IElementController;


Can probably remove this comment.

samhouts

elegant!

samhouts · 2017-09-12T20:03:04Z

Xamarin.Forms.Platform.Android/VisualElementPackager.cs

-		public VisualElementPackager(IVisualElementRenderer renderer)
+		VisualElement _element;
+
+		IElementController ElementController => _element;// _renderer.Element as IElementController;


Remove commented code

samhouts · 2017-09-12T20:05:05Z

Xamarin.Forms.Core/Layout.cs

@@ -237,6 +237,13 @@ protected void UpdateChildrenLayout()
 			double w = Math.Max(0, width - Padding.HorizontalThickness);
 			double h = Math.Max(0, height - Padding.VerticalThickness);

+			var isHeadless = CompressedLayout.GetIsHeadless(this);
+			var headlessOffset = CompressedLayout.GetHeadlessOffset(this);
+			for (var i = 0; i < LogicalChildrenInternal.Count; i++) {


Braces on their own lines. You're in Core territory, now! muwahaha

don't scratch that itch! :)

fixed by removing the braces.

samhouts · 2017-09-12T20:17:57Z

Xamarin.Forms.Platform.Android/VisualElementPackager.cs

-			if (_childViews == null)
-				_childViews = new List<IVisualElementRenderer>();
+			if (CompressedLayout.GetIsHeadless(view)) {
+				var _packager = new VisualElementPackager(_renderer, view);


the underscore in the variable name is a little confusing here, I think.

fixed. at some point that variable was a field...

adrianknight89 · 2017-09-13T02:23:23Z

compressed layouts can't have BG colors, gesture recognizers
no transformation

Are these limitations permanent or to be fixed in the future?

<ContentView Padding="6" CompressedLayout.IsHeadless="true" BackgroundColor="Pink" >

Should there be a compile-time / run-time error for this instead of silent fail of the bgcolor set? The reason I ask this is I don't like it when people pollute their visual tree with redundant stuff. If bgcolor has no use there, then it shouldn't be there?

StephaneDelcroix · 2017-09-13T07:29:26Z

@adrianknight89 at this point we have no plan for supporting BgColor on headless layouts, nor do we have plans for validating that case

alexsorokoletov · 2017-09-25T19:17:19Z

@StephaneDelcroix thank you for this PR and this feature. Wondering, where can one read about limitations and why they are there. Maybe it's just me can't find the information

bentmar · 2017-10-23T08:23:22Z

Can we please have some more information on how to use this?

davidortinau · 2017-10-24T03:18:46Z

@bentmar I'll have a blog out shortly with more samples, and then docs to come. Really any layout that you don't need a background on, doesn't transform, and doesn't accept gestures is a candidate. So just add CompressedLayout.IsHeadless="true" to it. I suspect we may discover some other cons as we test further. So far the reduction of renderers created is looking good, especially if you have lots of layout nesting. In my page I saw nearly a 50% reduction, though granted it was a poorly constructed page in many respects to begin with.

alexsorokoletov · 2017-10-26T21:26:08Z

https://blog.xamarin.com/3-big-things-explore-xamarin-forms-2-5-0-pre-release/

BlueRaja · 2017-11-10T16:18:52Z

Seems like this should be on by default, and only disabled when there's a background/transform/gesture/explicitly disabled?

* Implement vertical accuracy in GeoLocation API (#1103) * Location: add property 'VerticalAccuracy' (#1099) * vertical accuracy is only available in Android API level 26 and above (#1099) * update Samples app to show vertical accuracy on GeolocationPage * add missing documentation bits for Location.VerticalAccuracy * .gitattributes: get better diff context for C# code (#1115) * Location.VerticalAccuracy: add runtime check for Android version (#1099) (#1116) * the compile-time check is not enough * it crashed on old Android versions (<8.0) * GH-1102 Fix launcher on older devices (#1120) * Update Launcher.ios.tvos.cs * OpenUrlAsync was introduced in iOS 10 not 12 https://docs.microsoft.com/en-us/dotnet/api/uikit.uiapplication.openurlasync?view=xamarin-ios-sdk-12 * Fix trailing whitespace * Really? fix whitespace * Really! Fix whitespace * Fixes #1129 - set empty required declarations on UWP (#1133) * Fixes #1129 - set empty required declarations on UWP * Update Permissions.uwp.cs * Update Xamarin.Essentials.csproj (#1136) * GH-1142 AccessBackgroundLocation only when compile & running Q (#1143) * AccessBackgroundLocation only when compile & running Q * put if compile check around permission * GH-1121 If VC is null use TraitCollection (#1144) * Fixes #1123 (#1126) * Update PlacemarkExtensions.xml (#1132) Co-authored-by: Janus Weil <janus@gcc.gnu.org> Co-authored-by: James Montemagno <james.montemagno@gmail.com> Co-authored-by: Michael <Michael@ZPF.fr>

* Implement vertical accuracy in GeoLocation API (#1103) * Location: add property 'VerticalAccuracy' (#1099) * vertical accuracy is only available in Android API level 26 and above (#1099) * update Samples app to show vertical accuracy on GeolocationPage * add missing documentation bits for Location.VerticalAccuracy * .gitattributes: get better diff context for C# code (#1115) * Location.VerticalAccuracy: add runtime check for Android version (#1099) (#1116) * the compile-time check is not enough * it crashed on old Android versions (<8.0) * GH-1102 Fix launcher on older devices (#1120) * Update Launcher.ios.tvos.cs * OpenUrlAsync was introduced in iOS 10 not 12 https://docs.microsoft.com/en-us/dotnet/api/uikit.uiapplication.openurlasync?view=xamarin-ios-sdk-12 * Fix trailing whitespace * Really? fix whitespace * Really! Fix whitespace * Fixes #1129 - set empty required declarations on UWP (#1133) * Fixes #1129 - set empty required declarations on UWP * Update Permissions.uwp.cs * Update Xamarin.Essentials.csproj (#1136) * GH-1142 AccessBackgroundLocation only when compile & running Q (#1143) * AccessBackgroundLocation only when compile & running Q * put if compile check around permission * GH-1121 If VC is null use TraitCollection (#1144) * Fixes #1123 (#1126) * Update PlacemarkExtensions.xml (#1132) Co-authored-by: Janus Weil <janus@gcc.gnu.org> Co-authored-by: James Montemagno <james.montemagno@gmail.com> Co-authored-by: Michael <Michael@ZPF.fr> Co-authored-by: Jonathan Dick <jodick@microsoft.com> Co-authored-by: Janus Weil <janus@gcc.gnu.org> Co-authored-by: Michael <Michael@ZPF.fr>

[C, iOS, Android] LayoutCompression

32a63b3

dnfclas added the cla-required label Sep 12, 2017

StephaneDelcroix added cla-not-required and removed cla-required labels Sep 12, 2017

StephaneDelcroix requested review from jassmith and hartez September 12, 2017 08:46

fix docs

8db6e9e

hartez suggested changes Sep 12, 2017

View reviewed changes

samhouts reviewed Sep 12, 2017

View reviewed changes

StephaneDelcroix added 2 commits September 13, 2017 09:41

minor fixups

dab9d62

Merge branch 'master' into LayoutCompression

106cdd1

StephaneDelcroix merged commit 8ee62e8 into master Sep 13, 2017

StephaneDelcroix deleted the LayoutCompression branch September 13, 2017 09:19

samhouts added D-15.5 and removed cla-not-required labels Oct 10, 2017

michaeldwan mentioned this pull request Jan 5, 2018

ViewCell - Specified CAST is not valid (iOS) #1424

Closed

samhouts added this to the 2.5.0 milestone May 5, 2018

samhouts modified the milestones: 2.5.0, 2.3.0 Jun 27, 2018

samhouts modified the milestones: 2.5.0, 2.3.0 Aug 23, 2019

melimion mentioned this pull request Jun 2, 2020

About the 1675 open bugs in Xamarin.Forms dotnet/maui#109

Closed

mattleibow pushed a commit that referenced this pull request Jan 28, 2021

Update Xamarin.Essentials.csproj (#1136)

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[C, iOS, Android] LayoutCompression #1136

[C, iOS, Android] LayoutCompression #1136

StephaneDelcroix commented Sep 12, 2017 •

edited by samhouts

hartez Sep 12, 2017

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StephaneDelcroix Sep 13, 2017

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adrianknight89 commented Sep 13, 2017

StephaneDelcroix commented Sep 13, 2017

alexsorokoletov commented Sep 25, 2017

bentmar commented Oct 23, 2017

davidortinau commented Oct 24, 2017

alexsorokoletov commented Oct 26, 2017

BlueRaja commented Nov 10, 2017

[C, iOS, Android] LayoutCompression #1136

[C, iOS, Android] LayoutCompression #1136

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StephaneDelcroix commented Sep 12, 2017 • edited by samhouts

Description of Change

Bugs Fixed

API Changes

Behavioral Changes

PR Checklist

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adrianknight89 commented Sep 13, 2017

StephaneDelcroix commented Sep 13, 2017

alexsorokoletov commented Sep 25, 2017

bentmar commented Oct 23, 2017

davidortinau commented Oct 24, 2017

alexsorokoletov commented Oct 26, 2017

BlueRaja commented Nov 10, 2017

StephaneDelcroix commented Sep 12, 2017 •

edited by samhouts