From cf533a7b6d6607aefd39c06978578bb2b453eb3d Mon Sep 17 00:00:00 2001
From: Eduardo Speroni <edusperoni@users.noreply.github.com>
Date: Fri, 10 May 2019 05:05:28 -0300
Subject: [PATCH] feat(android): elevation shadow support (#7136)

---
 apps/app/ui-tests-app/css/elevation.css       | 43 ++++++++++
 apps/app/ui-tests-app/css/elevation.ts        | 20 +++++
 apps/app/ui-tests-app/css/elevation.xml       | 25 ++++++
 apps/app/ui-tests-app/css/main-page.ts        |  1 +
 tns-core-modules/ui/button/button.android.ts  | 26 +++++-
 .../ui/core/view-base/view-base.ts            |  2 +-
 tns-core-modules/ui/core/view/view-common.ts  | 14 ++++
 tns-core-modules/ui/core/view/view.android.ts | 84 ++++++++++++++++++-
 tns-core-modules/ui/core/view/view.d.ts       | 10 +++
 .../ui/styling/style-properties.ts            |  6 ++
 tns-core-modules/ui/styling/style/style.d.ts  |  8 +-
 tns-core-modules/ui/styling/style/style.ts    |  8 +-
 12 files changed, 236 insertions(+), 11 deletions(-)
 create mode 100644 apps/app/ui-tests-app/css/elevation.css
 create mode 100644 apps/app/ui-tests-app/css/elevation.ts
 create mode 100644 apps/app/ui-tests-app/css/elevation.xml

diff --git a/apps/app/ui-tests-app/css/elevation.css b/apps/app/ui-tests-app/css/elevation.css
new file mode 100644
index 000000000..5ebb8a2ab
--- /dev/null
+++ b/apps/app/ui-tests-app/css/elevation.css
@@ -0,0 +1,43 @@
+Label, Button {
+    text-align: center;
+    padding: 10;
+    margin: 16;
+    background-color: #bbb;
+}
+
+.elevation-0 {
+    android-elevation: 0;
+}
+
+.elevation-2 {
+    android-elevation: 2;
+}
+
+.elevation-4 {
+    android-elevation: 4;
+}
+
+.elevation-4:highlighted {
+    android-elevation: 2;
+}
+
+.elevation-8 {
+    android-elevation: 8;
+}
+
+.elevation-10 {
+    android-elevation: 10;
+}
+
+.pressed-z-10 {
+    android-dynamic-elevation-offset: 10;
+}
+
+.round {
+    color: #fff;
+    background-color: #ff1744;
+    border-radius: 50%; /* TODO kills elevation */
+    width: 80;
+    height: 80;
+    android-elevation: 8;
+}
\ No newline at end of file
diff --git a/apps/app/ui-tests-app/css/elevation.ts b/apps/app/ui-tests-app/css/elevation.ts
new file mode 100644
index 000000000..dd7e54701
--- /dev/null
+++ b/apps/app/ui-tests-app/css/elevation.ts
@@ -0,0 +1,20 @@
+import { Button } from "tns-core-modules/ui/button/button";
+import { EventData } from "tns-core-modules/ui/page/page";
+
+const states = [
+    { class: "", text: "default elevation" },
+    { class: "elevation-10", text: "elevetion 10" },
+    { class: "elevation-10 pressed-z-10", text: "elevetion 10 pressed-z 10" },
+    { class: "elevation-0", text: "elevetion 0" },
+]
+let currentState = 0;
+
+export function buttonTap(args: EventData) {
+    let btn: Button = args.object as Button;
+    currentState++;
+    if (currentState >= states.length) {
+        currentState = 0;
+    }
+    btn.className = states[currentState].class;
+    btn.text = states[currentState].text;
+}
\ No newline at end of file
diff --git a/apps/app/ui-tests-app/css/elevation.xml b/apps/app/ui-tests-app/css/elevation.xml
new file mode 100644
index 000000000..37a492e92
--- /dev/null
+++ b/apps/app/ui-tests-app/css/elevation.xml
@@ -0,0 +1,25 @@
+<Page xmlns="http://schemas.nativescript.org/tns.xsd" loaded="onLoaded">
+    <ScrollView>
+        <StackLayout backgroundColor="aliceblue" androidElevation="2" padding="10" margin="20">
+            <Button text="default elevation" tap="buttonTap"/>
+
+            <Button class="elevation-0" text="elevation 0"/>
+
+            <Label class="elevation-2" text="Label with elevation 2"/>
+
+            <StackLayout androidElevation="4" backgroundColor="#ff1744" horizontalAlignment="center" margin="20">
+                <Button class="elevation-2" text="elevation 2"/>
+                <Button class="elevation-4" text="elevation 4"/>
+            </StackLayout>
+
+            <StackLayout orientation="horizontal" horizontalAlignment="center">
+                <Button class="round" androidElevation="4" text="el. 4"/>
+                <Button class="elevation-8 round" text="el. 8"/>
+            </StackLayout>
+
+            <Label class="elevation-8" text="elevation 8"/>
+            <Button class="elevation-8" text="elevation 8, with radius" borderRadius="4"/>
+            <Button class="elevation-10" text="elevation 10"/>
+        </StackLayout>
+    </ScrollView>
+</Page>
\ No newline at end of file
diff --git a/apps/app/ui-tests-app/css/main-page.ts b/apps/app/ui-tests-app/css/main-page.ts
index 464da8189..c892c71ea 100644
--- a/apps/app/ui-tests-app/css/main-page.ts
+++ b/apps/app/ui-tests-app/css/main-page.ts
@@ -38,6 +38,7 @@ export function loadExamples() {
     examples.set("margins-paddings-with-percentage", "css/margins-paddings-with-percentage");
     examples.set("padding-and-border", "css/padding-and-border");
     examples.set("combinators", "css/combinators");
+    examples.set("elevation", "css/elevation");
     examples.set("styled-formatted-text", "css/styled-formatted-text");
     examples.set("non-uniform-radius", "css/non-uniform-radius");
     examples.set("missing-background-image", "css/missing-background-image");
diff --git a/tns-core-modules/ui/button/button.android.ts b/tns-core-modules/ui/button/button.android.ts
index 66db08e2d..2a2104652 100644
--- a/tns-core-modules/ui/button/button.android.ts
+++ b/tns-core-modules/ui/button/button.android.ts
@@ -3,11 +3,16 @@
     paddingLeftProperty, paddingTopProperty, paddingRightProperty, paddingBottomProperty,
     Length, zIndexProperty, textAlignmentProperty, TextAlignment
 } from "./button-common";
+import { androidElevationProperty, androidDynamicElevationOffsetProperty } from "../styling/style-properties";
 import { profile } from "../../profiling";
 import { TouchGestureEventData, GestureTypes, TouchAction } from "../gestures";
+import { device } from "../../platform";
+import lazy from "../../utils/lazy";
 
 export * from "./button-common";
 
+const sdkVersion = lazy(() => parseInt(device.sdkVersion));
+
 interface ClickListener {
     new(owner: Button): android.view.View.OnClickListener;
 }
@@ -146,9 +151,28 @@ export class Button extends ButtonBase {
         org.nativescript.widgets.ViewHelper.setZIndex(this.nativeViewProtected, value);
     }
 
+    [androidElevationProperty.getDefault](): number {
+        if (sdkVersion() < 21) {
+            return 0;
+        }
+
+        // NOTE: Button widget has StateListAnimator that defines the elevation value and
+        // at the time of the getDefault() query the animator is not applied yet so we
+        // return the hardcoded @dimen/button_elevation_material value 2dp here instead
+        return 2;
+    }
+
+    [androidDynamicElevationOffsetProperty.getDefault](): number {
+        if (sdkVersion() < 21) {
+            return 0;
+        }
+
+        return 4; // 4dp @dimen/button_pressed_z_material
+    }
+
     [textAlignmentProperty.setNative](value: TextAlignment) {
         // Button initial value is center.
         const newValue = value === "initial" ? "center" : value;
         super[textAlignmentProperty.setNative](newValue);
     }
-}
\ No newline at end of file
+}
diff --git a/tns-core-modules/ui/core/view-base/view-base.ts b/tns-core-modules/ui/core/view-base/view-base.ts
index 1863ce05d..caf868b0c 100644
--- a/tns-core-modules/ui/core/view-base/view-base.ts
+++ b/tns-core-modules/ui/core/view-base/view-base.ts
@@ -1018,7 +1018,7 @@ export const classNameProperty = new Property<ViewBase, string>({
     valueChanged(view: ViewBase, oldValue: string, newValue: string) {
         let classes = view.cssClasses;
         classes.clear();
-        if (typeof newValue === "string") {
+        if (typeof newValue === "string" && newValue !== "") {
             newValue.split(" ").forEach(c => classes.add(c));
         }
         view._onCssStateChange();
diff --git a/tns-core-modules/ui/core/view/view-common.ts b/tns-core-modules/ui/core/view/view-common.ts
index 26acd3e68..166f2205e 100644
--- a/tns-core-modules/ui/core/view/view-common.ts
+++ b/tns-core-modules/ui/core/view/view-common.ts
@@ -683,6 +683,20 @@ export abstract class ViewCommon extends ViewBase implements ViewDefinition {
         this.style.scaleY = value;
     }
 
+    get androidElevation(): number {
+        return this.style.androidElevation;
+    }
+    set androidElevation(value: number) {
+        this.style.androidElevation = value;
+    }
+
+    get androidDynamicElevationOffset(): number {
+        return this.style.androidDynamicElevationOffset;
+    }
+    set androidDynamicElevationOffset(value: number) {
+        this.style.androidDynamicElevationOffset = value;
+    }
+
     //END Style property shortcuts
 
     public automationText: string;
diff --git a/tns-core-modules/ui/core/view/view.android.ts b/tns-core-modules/ui/core/view/view.android.ts
index 7e27b8e5a..7c4e92e60 100644
--- a/tns-core-modules/ui/core/view/view.android.ts
+++ b/tns-core-modules/ui/core/view/view.android.ts
@@ -15,19 +15,27 @@ import {
     minWidthProperty, minHeightProperty, widthProperty, heightProperty,
     marginLeftProperty, marginTopProperty, marginRightProperty, marginBottomProperty,
     rotateProperty, scaleXProperty, scaleYProperty, translateXProperty, translateYProperty,
-    zIndexProperty, backgroundInternalProperty
+    zIndexProperty, backgroundInternalProperty, androidElevationProperty, androidDynamicElevationOffsetProperty
 } from "../../styling/style-properties";
 
 import { Background, ad as androidBackground } from "../../styling/background";
 import { profile } from "../../../profiling";
 import { topmost } from "../../frame/frame-stack";
 import { AndroidActivityBackPressedEventData, android as androidApp } from "../../../application";
+import { device } from "../../../platform";
+import lazy from "../../../utils/lazy";
 
 export * from "./view-common";
 
 const DOMID = "_domId";
 const androidBackPressedEvent = "androidBackPressed";
 
+const shortAnimTime = 17694720; // android.R.integer.config_shortAnimTime
+const statePressed = 16842919; // android.R.attr.state_pressed
+const stateEnabled = 16842910; // android.R.attr.state_enabled
+
+const sdkVersion = lazy(() => parseInt(device.sdkVersion));
+
 const modalMap = new Map<number, DialogOptions>();
 
 let TouchListener: TouchListener;
@@ -255,6 +263,8 @@ export class View extends ViewCommon {
     private layoutChangeListener: android.view.View.OnLayoutChangeListener;
     private _manager: android.support.v4.app.FragmentManager;
     private _rootManager: android.support.v4.app.FragmentManager;
+    private _originalElevation: number;
+    private _originalStateListAnimator: any; /* android.animation.StateListAnimator; */
 
     nativeViewProtected: android.view.View;
 
@@ -709,6 +719,74 @@ export class View extends ViewCommon {
         this.nativeViewProtected.setAlpha(float(value));
     }
 
+    [androidElevationProperty.getDefault](): number {
+        if (sdkVersion() < 21) {
+            return 0;
+        }
+
+        // NOTE: overriden in Button implementation as for widgets with StateListAnimator (Button)
+        // nativeView.getElevation() returns 0 at the time of the getDefault() query
+        return layout.toDeviceIndependentPixels((<any>this.nativeViewProtected).getElevation());
+    }
+    [androidElevationProperty.setNative](value: number) {
+        if (sdkVersion() < 21) {
+            return;
+        }
+
+        this.refreshStateListAnimator();
+    }
+
+    [androidDynamicElevationOffsetProperty.getDefault](): number {
+        return 0;
+    }
+    [androidDynamicElevationOffsetProperty.setNative](value: number) {
+        if (sdkVersion() < 21) {
+            return;
+        }
+
+        this.refreshStateListAnimator();
+    }
+
+    private refreshStateListAnimator() {
+        const nativeView: any = this.nativeViewProtected;
+
+        const ObjectAnimator = android.animation.ObjectAnimator;
+        const AnimatorSet = android.animation.AnimatorSet;
+
+        const duration = nativeView.getContext().getResources().getInteger(shortAnimTime) / 2;
+        const elevation = layout.toDevicePixels(this.androidElevation || 0);
+        const z = layout.toDevicePixels(0);
+        const pressedZ = layout.toDevicePixels(this.androidDynamicElevationOffset || 0);
+
+        const pressedSet = new AnimatorSet();
+        pressedSet.playTogether(java.util.Arrays.asList([
+            ObjectAnimator.ofFloat(nativeView, "translationZ", [pressedZ])
+                .setDuration(duration),
+            ObjectAnimator.ofFloat(nativeView, "elevation", [elevation])
+                .setDuration(0),
+        ]));
+
+        const notPressedSet = new AnimatorSet();
+        notPressedSet.playTogether(java.util.Arrays.asList([
+            ObjectAnimator.ofFloat(nativeView, "translationZ", [z])
+                .setDuration(duration),
+            ObjectAnimator.ofFloat(nativeView, "elevation", [elevation])
+                .setDuration(0),
+        ]));
+
+        const defaultSet = new AnimatorSet();
+        defaultSet.playTogether(java.util.Arrays.asList([
+            ObjectAnimator.ofFloat(nativeView, "translationZ", [0]).setDuration(0),
+            ObjectAnimator.ofFloat(nativeView, "elevation", [0]).setDuration(0),
+        ]));
+
+        const stateListAnimator = new (<any>android.animation).StateListAnimator();
+        stateListAnimator.addState([statePressed, stateEnabled], pressedSet);
+        stateListAnimator.addState([stateEnabled], notPressedSet);
+        stateListAnimator.addState([], defaultSet);
+        nativeView.setStateListAnimator(stateListAnimator);
+    }
+
     [horizontalAlignmentProperty.getDefault](): HorizontalAlignment {
         return <HorizontalAlignment>org.nativescript.widgets.ViewHelper.getHorizontalAlignment(this.nativeViewProtected);
     }
@@ -946,7 +1024,7 @@ function createNativePercentLengthProperty(options: NativePercentLengthPropertyO
     const { getter, setter, auto = 0 } = options;
     let setPixels, getPixels, setPercent;
     if (getter) {
-        View.prototype[getter] = function (this: View): PercentLength {
+        View.prototype[getter] = function(this: View): PercentLength {
             if (options) {
                 setPixels = options.setPixels;
                 getPixels = options.getPixels;
@@ -962,7 +1040,7 @@ function createNativePercentLengthProperty(options: NativePercentLengthPropertyO
         }
     }
     if (setter) {
-        View.prototype[setter] = function (this: View, length: PercentLength) {
+        View.prototype[setter] = function(this: View, length: PercentLength) {
             if (options) {
                 setPixels = options.setPixels;
                 getPixels = options.getPixels;
diff --git a/tns-core-modules/ui/core/view/view.d.ts b/tns-core-modules/ui/core/view/view.d.ts
index 9b9fb84d9..5325ab9ed 100644
--- a/tns-core-modules/ui/core/view/view.d.ts
+++ b/tns-core-modules/ui/core/view/view.d.ts
@@ -224,6 +224,16 @@ export abstract class View extends ViewBase {
      */
     color: Color;
 
+    /**
+     * Gets or sets the elevation of the android view.
+     */
+    androidElevation: number;
+
+    /**
+     * Gets or sets the dynamic elevation offset of the android view.
+     */
+    androidDynamicElevationOffset: number;
+
     /**
      * Gets or sets the background style property.
      */
diff --git a/tns-core-modules/ui/styling/style-properties.ts b/tns-core-modules/ui/styling/style-properties.ts
index 185446827..0963cf353 100644
--- a/tns-core-modules/ui/styling/style-properties.ts
+++ b/tns-core-modules/ui/styling/style-properties.ts
@@ -1099,3 +1099,9 @@ export const visibilityProperty = new CssProperty<Style, Visibility>({
     }
 });
 visibilityProperty.register(Style);
+
+export const androidElevationProperty = new CssProperty<Style, number>({ name: "androidElevation", cssName: "android-elevation", valueConverter: parseFloat });
+androidElevationProperty.register(Style);
+
+export const androidDynamicElevationOffsetProperty = new CssProperty<Style, number>({ name: "androidDynamicElevationOffset", cssName: "android-dynamic-elevation-offset", valueConverter: parseFloat });
+androidDynamicElevationOffsetProperty.register(Style);
diff --git a/tns-core-modules/ui/styling/style/style.d.ts b/tns-core-modules/ui/styling/style/style.d.ts
index b7c0091c8..a337088d8 100644
--- a/tns-core-modules/ui/styling/style/style.d.ts
+++ b/tns-core-modules/ui/styling/style/style.d.ts
@@ -92,6 +92,8 @@ export class Style extends Observable {
     public fontWeight: FontWeight;
     public font: string;
 
+    public androidElevation: number;
+    public androidDynamicElevationOffset: number;
     public zIndex: number;
     public opacity: number;
     public visibility: Visibility;
@@ -127,13 +129,13 @@ export class Style extends Observable {
     public selectedTabTextColor: Color;
     public androidSelectedTabHighlightColor: Color;
 
-    // ListView-specific props 
+    // ListView-specific props
     public separatorColor: Color;
 
     //SegmentedBar-specific props
     public selectedBackgroundColor: Color;
 
-    // Page-specific props 
+    // Page-specific props
     public statusBarStyle: "light" | "dark";
     public androidStatusBarBackground: Color;
 
@@ -167,4 +169,4 @@ interface PropertyBagClass {
 }
 interface PropertyBag {
     [property: string]: string;
-}
\ No newline at end of file
+}
diff --git a/tns-core-modules/ui/styling/style/style.ts b/tns-core-modules/ui/styling/style/style.ts
index 656aa14f9..a16d83e95 100644
--- a/tns-core-modules/ui/styling/style/style.ts
+++ b/tns-core-modules/ui/styling/style/style.ts
@@ -65,6 +65,8 @@ export class Style extends Observable implements StyleDefinition {
     public fontWeight: FontWeight;
     public font: string;
 
+    public androidElevation: number;
+    public androidDynamicElevationOffset: number;
     public zIndex: number;
     public opacity: number;
     public visibility: Visibility;
@@ -100,13 +102,13 @@ export class Style extends Observable implements StyleDefinition {
     public selectedTabTextColor: Color;
     public androidSelectedTabHighlightColor: Color;
 
-    // ListView-specific props 
+    // ListView-specific props
     public separatorColor: Color;
 
     //SegmentedBar-specific props
     public selectedBackgroundColor: Color;
 
-    // Page-specific props 
+    // Page-specific props
     public statusBarStyle: "light" | "dark";
     public androidStatusBarBackground: Color;
 
@@ -124,4 +126,4 @@ export class Style extends Observable implements StyleDefinition {
 
     public PropertyBag: { new(): { [property: string]: string }, prototype: { [property: string]: string } };
 }
-Style.prototype.PropertyBag = class { [property: string]: string; }
\ No newline at end of file
+Style.prototype.PropertyBag = class { [property: string]: string; }