Merge pull request #2269 from NativeScript/cankov/label-smart-layout-invalidation

Layout will not requestLayout when its text is changed if it has fixed size

tests/app/ui/label/label-tests.ts

@@ -1,4 +1,4 @@
-import TKUnit = require("../../TKUnit");
+import * as TKUnit from "../../TKUnit";
 import testModule = require("../../ui-test");
 import styling = require("ui/styling");
 
@@ -17,6 +17,13 @@ import labelTestsNative = require("./label-tests-native");
 import fs = require("file-system");
 import background = require("ui/styling/background");
 
+import {StackLayout} from "ui/layouts/stack-layout";
+import {GridLayout} from "ui/layouts/grid-layout";
+import {isIOS} from "platform";
+import {Label} from "ui/label";
+import {LayoutBase} from  "ui/layouts/layout-base";
+import * as helper from "../helper";
+
 export class LabelTest extends testModule.UITest<LabelModule.Label> {
 
     public create(): LabelModule.Label {
@@ -524,8 +531,77 @@ export class LabelTest extends testModule.UITest<LabelModule.Label> {
         page.addCss("label { < !--Test wrong comment-- > background-color: red; }");
         TKUnit.assertNotEqual(this.errorMessage, undefined);
     }
+
+    private requestLayoutFixture(expectRequestLayout: boolean, setup: (label: Label) => LayoutBase): void {
+        if (!isIOS) {
+            return;
+        }
+
+        let label = new Label();
+        let host = setup(label);
+
+        host.addChild(label);
+
+        let mainPage = helper.getCurrentPage();
+        mainPage.content = host;
+        TKUnit.waitUntilReady(() => host.isLoaded);
+
+        let called = false;
+        label.requestLayout = () => called = true;
+        label.text = "Hello World";
+
+        if (expectRequestLayout) {
+            TKUnit.assertTrue(called, "label.requestLayout should be called.");
+        } else {
+            TKUnit.assertFalse(called, "image.requestLayout should not be called.");
+        }
+    }
+
+    public test_SettingTextWhenInFixedSizeGridShouldNotRequestLayout() {
+        this.requestLayoutFixture(false, () => {
+            let host = new GridLayout();
+            host.width = 100;
+            host.height = 100;
+            return host;
+        });
+    }
+
+    public test_SettingTextWhenFixedWidthAndHeightDoesNotRequestLayout() {
+        this.requestLayoutFixture(false, label => {
+            let host = new StackLayout();
+            label.width = 100;
+            label.height = 100;
+            return host;
+        });
+    };
+
+    public test_SettingTextWhenSizedToContentShouldInvalidate() {
+        this.requestLayoutFixture(true, () => {
+            let host = new StackLayout();
+            host.orientation = "horizontal";
+            return host;
+        });
+    };
+
+    public test_SettingTextOnSingleLineTextWhenWidthIsSizedToParentAndHeightIsSizedToContentShouldNotRequestLayout() {
+        this.requestLayoutFixture(false, () => {
+            let host = new StackLayout();
+            host.width = 100;
+            return host;
+        });
+    }
+
+    public test_SettingTextOnMultilineLineTextWhenWidthIsSizedToParentAndHeightIsSizedToContentShouldRequestLayout() {
+        this.requestLayoutFixture(true, label => {
+            label.textWrap = true;
+            let host = new StackLayout();
+            host.width = 100;
+            return host;
+        });
+    }
 }
 
 export function createTestCase(): LabelTest {
     return new LabelTest();
 }
+

tns-core-modules/ui/label/label.ios.ts

@@ -57,8 +57,16 @@ class UILabelImpl extends UILabel {
     }
 }
 
+enum FixedSize {
+    NONE = 0,
+    WIDTH = 1,
+    HEIGHT = 2,
+    BOTH = 3
+}
+
 export class Label extends common.Label {
     private _ios: UILabel;
+    private _fixedSize: FixedSize;
 
     constructor() {
         super();
@@ -81,6 +89,17 @@ export class Label extends common.Label {
         this.style._updateTextDecoration();
         this.style._updateTextTransform();
     }
+    
+    _requestLayoutOnTextChanged(): void {
+        if (this._fixedSize === FixedSize.BOTH) {
+            return;
+        }
+        if (this._fixedSize === FixedSize.WIDTH && !this.textWrap) {
+            // Single line label with fixed width will skip request layout on text change.
+            return;
+        }
+        super._requestLayoutOnTextChanged();
+    }
 
     public onMeasure(widthMeasureSpec: number, heightMeasureSpec: number): void {
         var nativeView = this._nativeView;
@@ -99,6 +118,9 @@ export class Label extends common.Label {
                 height = Number.POSITIVE_INFINITY;
             }
 
+            this._fixedSize = (widthMode === utils.layout.EXACTLY ? FixedSize.WIDTH : FixedSize.NONE)
+                            | (heightMode === utils.layout.EXACTLY ? FixedSize.HEIGHT : FixedSize.NONE);
+
             var nativeSize = nativeView.sizeThatFits(CGSizeMake(width, height));
             var labelWidth = nativeSize.width;
 

tns-core-modules/ui/text-base/text-base-common.ts

@@ -17,7 +17,7 @@ function ensureWeakEvents() {
 var textProperty = new dependencyObservable.Property(
     "text",
     "TextBase",
-    new proxy.PropertyMetadata("", dependencyObservable.PropertyMetadataSettings.AffectsLayout)
+    new proxy.PropertyMetadata("", dependencyObservable.PropertyMetadataSettings.None)
 );
 
 var formattedTextProperty = new dependencyObservable.Property(
@@ -127,6 +127,10 @@ export class TextBase extends view.View implements definition.TextBase, formatte
     public _addChildFromBuilder(name: string, value: any): void {
         formattedString.FormattedString.addFormattedStringToView(this, name, value);
     }
+
+    _requestLayoutOnTextChanged(): void {
+        this.requestLayout();
+    }
 }
 
 tbs.TextBaseStyler.registerHandlers()

tns-core-modules/ui/text-base/text-base.d.ts

@@ -49,6 +49,11 @@
         //@private
         _onTextPropertyChanged(data: dependencyObservable.PropertyChangeData): void;
         _setFormattedTextPropertyToNative(value: any): void;
+        /**
+         * @private
+         * Called when the text property is changed to request layout.
+         */
+        _requestLayoutOnTextChanged(): void;
         //@endprivate
     }
 }

tns-core-modules/ui/text-base/text-base.ios.ts

@@ -8,6 +8,7 @@ export class TextBase extends common.TextBase {
         this.ios.text = newValue;
         this.style._updateTextDecoration();
         this.style._updateTextTransform();
+        this._requestLayoutOnTextChanged();
     }
 
     public _setFormattedTextPropertyToNative(value) {