Merge pull request #2909 from NativeScript/its

ListView item template selector

apps/app/ui-tests-app/list-view/list-view.css

@@ -0,0 +1,8 @@
+Label, Button {
+    font-size: 8;
+}
+
+ListView {
+    border-width: 1;
+    margin: 1;
+}

apps/app/ui-tests-app/list-view/list-view.ts

@@ -0,0 +1,60 @@
+import { EventData } from 'data/observable';
+import { ObservableArray } from "data/observable-array";
+import { View, KeyedTemplate } from "ui/core/view";
+import { Page } from 'ui/page';
+import { ViewModel, Item } from './main-view-model';
+import { ListView } from "ui/list-view";
+import { Label } from "ui/label";
+import { GridLayout } from "ui/layouts/grid-layout";
+import { Color } from "color";
+
+export function selectItemTemplate(item: Item, index: number, items: ObservableArray<Item>): string {
+    return item.id % 10 === 0 ? "red" : item.id % 2 === 0 ? "green" : "yellow"; 
+}
+
+export function pageLoaded(args: EventData) {
+  let page = <Page>args.object;
+  page.bindingContext = new ViewModel();
+
+  let lv4 = page.getViewById<ListView>("lv4");
+  lv4.itemTemplateSelector = (item: Item, index: number, items: ObservableArray<Item>) => {
+    return index % 10 === 0 ? "red" : index % 2 === 0 ? "green" : "yellow"; 
+  };
+
+  let createLabel = (backgroundColor: Color) => { 
+    let label = new Label(); 
+    label.bind({
+        sourceProperty: null,
+        targetProperty: "text",
+        expression: "$value"
+    });
+    label.style.backgroundColor = backgroundColor;
+    return label;
+  };
+
+  lv4.itemTemplates = new Array<KeyedTemplate>(
+      {
+          key: "red",
+          createView: () => { return createLabel(new Color("red")); }
+      },
+      {
+          key: "green",
+          createView: () => { return createLabel(new Color("green")); }
+      },
+      {
+          key: "yellow",
+          createView: () => { return createLabel(new Color("yellow")); }
+      }
+  );
+}
+
+let scrollToBottom = true;
+export function onScroll(args: EventData){
+  let page = (<View>args.object).page;
+  let gridLayout = page.getViewById<GridLayout>("grid-layout");
+  for (let i = 0, length = gridLayout.getChildrenCount(); i < length; i++){
+      let listView = <ListView>gridLayout.getChildAt(i);
+      listView.scrollToIndex(scrollToBottom ? listView.items.length - 1 : 0);
+  }
+  scrollToBottom = !scrollToBottom;
+}

apps/app/ui-tests-app/list-view/list-view.xml

@@ -0,0 +1,50 @@
+<Page loaded="pageLoaded">
+    <StackLayout>
+        <Button text="SCROLL" tap="onScroll" height="30"/>
+        <GridLayout id="grid-layout" columns="*,*" rows="*,*">
+            <ListView id="lv1" col="0" row="0" items="{{ items }}" itemTemplateSelector="selectItemTemplate">
+                <ListView.itemTemplates>
+                    <template key="red">
+                        <Label text="{{ $value }}" textWrap="true" style.backgroundColor="red"/>
+                    </template>
+                    <template key="green">
+                        <Label text="{{ $value }}" textWrap="true" style.backgroundColor="green"/>
+                    </template>
+                    <template key="yellow">
+                        <Label text="{{ $value }}" textWrap="true" style.backgroundColor="yellow"/>
+                    </template>
+                </ListView.itemTemplates>
+            </ListView>
+            <ListView id="lv2" col="1" row="0" items="{{ items }}" itemTemplateSelector="id % 10 === 0 ? 'red' : id % 2 === 0 ? 'green' : 'yellow'">
+                <ListView.itemTemplates>
+                    <template key="red">
+                        <Label text="{{ $value }}" textWrap="true" style.backgroundColor="red"/>
+                    </template>
+                    <template key="green">
+                        <Label text="{{ $value }}" textWrap="true" style.backgroundColor="green"/>
+                    </template>
+                    <template key="yellow">
+                        <Label text="{{ $value }}" textWrap="true" style.backgroundColor="yellow"/>
+                    </template>
+                </ListView.itemTemplates>
+            </ListView>
+            <ListView id="lv3" col="0" row="1" items="{{ items }}" itemTemplateSelector="$index % 10 === 0 ? 'wrong' : $index % 2 === 0 ? 'green' : 'yellow'">
+                <ListView.itemTemplate>
+                    <Label text="{{ $value + ' itemTemplate' }}" textWrap="true"/>
+                </ListView.itemTemplate>
+                <ListView.itemTemplates>
+                    <template key="red">
+                        <Label text="{{ $value }}" textWrap="true" style.backgroundColor="red"/>
+                    </template>
+                    <template key="green">
+                        <Label text="{{ $value }}" textWrap="true" style.backgroundColor="green"/>
+                    </template>
+                    <template key="yellow">
+                        <Label text="{{ $value }}" textWrap="true" style.backgroundColor="yellow"/>
+                    </template>
+                </ListView.itemTemplates>
+            </ListView>
+            <ListView id="lv4" col="1" row="1" items="{{ items }}"></ListView>
+        </GridLayout>
+    </StackLayout>
+</Page>

apps/app/ui-tests-app/list-view/main-view-model.ts

@@ -0,0 +1,51 @@
+import { Observable } from 'data/observable';
+import { ObservableArray } from 'data/observable-array';
+
+export class Item extends Observable {
+  private _name: string;
+  private _id: number;
+
+  constructor(name: string, id: number) {
+    super();
+    this._name = name;
+    this._id = id;
+  }
+
+  get name(): string {
+    return this._name;
+  }
+
+  set name(value: string) {
+    if (this._name !== value) {
+      this._name = value;
+      this.notifyPropertyChange('name', value)
+    }
+  }
+
+  get id(): number {
+    return this._id;
+  }
+
+  set id(value: number) {
+    if (this._id !== value) {
+      this._id = value;
+      this.notifyPropertyChange('id', value)
+    }
+  }
+
+  public toString() {
+    return `${this.name} ${this.id}`;
+  }
+}
+
+export class ViewModel extends Observable {
+  private _items: ObservableArray<Item>;
+
+  get items(): ObservableArray<Item> {
+    this._items = new ObservableArray<Item>();
+    for (let i = 0; i < 100; i++){
+      this._items.push(new Item(`Item`, i));
+    }
+    return this._items;
+  }
+}

apps/app/ui-tests-app/mainPage.ts

@@ -36,6 +36,7 @@ export function pageLoaded(args: EventData) {
     examples.set("transitions", "transitions/page0");
     examples.set("segStyle", "segmented-bar/all");
     examples.set("flexBox", "flexbox/flexbox");
+    examples.set("list-view", "list-view/list-view");
 
     //examples.set("listview_binding", "pages/listview_binding");
     //examples.set("textfield", "text-field/text-field");

tests/app/ui/list-view/list-view-tests.ts

@@ -8,6 +8,7 @@ import utils = require("utils/utils");
 import { Label } from "ui/label";
 import helper = require("../helper");
 import { Page } from "ui/page";
+import { View, KeyedTemplate } from "ui/core/view";
 
 // >> article-require-listview-module
 import listViewModule = require("ui/list-view");
@@ -581,7 +582,7 @@ export class ListViewTest extends testModule.UITest<listViewModule.ListView> {
         if (platform.isAndroid) {
             // simulates Angular way of removing views
             (<any>listView)._realizedItems.forEach((view, nativeView, map) => {
-                console.log("view: " + view);
+                //console.log("view: " + view);
                 listView._removeView(view);
             });
             this.tearDown();
@@ -640,6 +641,7 @@ export class ListViewTest extends testModule.UITest<listViewModule.ListView> {
         for (let i = 0; i < count; i++) {
             items.push({
                 text: "Item " + i,
+                age: i,
                 loadedCount: 0,
                 unloadedCount: 0,
                 onViewLoaded: function onViewLoaded(args) {
@@ -767,10 +769,143 @@ export class ListViewTest extends testModule.UITest<listViewModule.ListView> {
     private waitUntilListViewReady(): void {
         TKUnit.waitUntilReady(() => this.getNativeViewCount(this.testView) === this.testView.items.length);
     }
+
+    // Multiple item templates tests
+    public test_ItemTemplateSelector_WhenWrongTemplateKeyIsSpecified_TheDefaultTemplateIsUsed() {
+        let listView = this.testView;
+        listView.height = 200;
+
+        listView.itemTemplate = "<Label text='default' minHeight='100' maxHeight='100'/>";
+        listView.itemTemplates = this._itemTemplatesString;
+        listView.itemTemplateSelector = "age % 2 === 0 ? 'wrong' : 'green'";
+        listView.items = ListViewTest.generateItemsForMultipleTemplatesTests(2);
+        TKUnit.wait(0.1);
+
+        let firstNativeElementText = this.getTextFromNativeElementAt(listView, 0);
+        
+        TKUnit.assertEqual(firstNativeElementText, "default", "first element text");
+    }
+
+    public test_ItemTemplateSelector_IsCorrectlyParsedFromString() {
+        let listView = this.testView;
+        listView.itemTemplateSelector = "age % 2 === 0 ? 'red' : 'green'";
+        let items = ListViewTest.generateItemsForMultipleTemplatesTests(2);
+        let itemTemplateSelectorFunction = <any>listView.itemTemplateSelector;
+        TKUnit.wait(0.1);
+
+        let templateKey0 = itemTemplateSelectorFunction(items[0], 0, items);
+        TKUnit.assertEqual(templateKey0, "red", "itemTemplateSelector result for first item");
+
+        let templateKey1 = itemTemplateSelectorFunction(items[1], 1, items);
+        TKUnit.assertEqual(templateKey1, "green", "itemTemplateSelector result for second item");
+    }
+
+    public test_ItemTemplateSelector_ItemTemplatesAreCorrectlyParsedFromString() {
+        let listView = this.testView;
+        listView.itemTemplates = this._itemTemplatesString;
+        
+        let itemTemplatesArray = <any>listView.itemTemplates;
+
+        TKUnit.assertEqual(itemTemplatesArray.length, 3, "itemTemplates array length");
+        
+        let template0 = <KeyedTemplate>itemTemplatesArray[0];
+        TKUnit.assertEqual(template0.key, "red", "template0.key");
+        TKUnit.assertEqual((<Label>template0.createView()).text, "red", "template0 created view text");
+        
+        let template1 = <KeyedTemplate>itemTemplatesArray[1];
+        TKUnit.assertEqual(template1.key, "green", "template1.key");
+        TKUnit.assertEqual((<Label>template1.createView()).text, "green", "template1 created view text");
+        
+        let template2 = <KeyedTemplate>itemTemplatesArray[2];
+        TKUnit.assertEqual(template2.key, "blue", "template2.key");
+        TKUnit.assertEqual((<Label>template2.createView()).text, "blue", "template2 created view text");
+    }
+
+    public test_ItemTemplateSelector_CorrectTemplateIsUsed() {
+        let listView = this.testView;
+        listView.height = 200;
+
+        listView.itemTemplates = this._itemTemplatesString;
+        listView.itemTemplateSelector = "age % 2 === 0 ? 'red' : 'green'";
+        listView.items = ListViewTest.generateItemsForMultipleTemplatesTests(4);
+        TKUnit.wait(0.1);
+
+        let firstNativeElementText = this.getTextFromNativeElementAt(listView, 0);
+        let secondNativeElementText = this.getTextFromNativeElementAt(listView, 1);
+        
+        TKUnit.assertEqual(firstNativeElementText, "red", "first element text");
+        TKUnit.assertEqual(secondNativeElementText, "green", "second element text");
+    }
+
+    public test_ItemTemplateSelector_TestVirtualization() {
+        let listView = this.testView;
+        listView.height = 300;
+
+        listView.itemTemplates = this._itemTemplatesString;
+        listView.itemTemplateSelector = "age % 2 === 0 ? 'red' : (age % 3 === 0 ? 'blue' : 'green')";
+        listView.items = ListViewTest.generateItemsForMultipleTemplatesTests(10);
+        TKUnit.wait(0.05);
+
+        // Forward
+        for(let i = 0, length = listView.items.length; i < length; i++){
+            listView.scrollToIndex(i);
+            TKUnit.wait(0.05);
+        }
+        
+        // Back
+        for(let i = listView.items.length - 1; i >= 0; i--){
+            listView.scrollToIndex(i);
+            TKUnit.wait(0.05);
+        }
+
+        if (listView.android){
+            //(<any>listView)._dumpRealizedTemplates();
+            let realizedItems = <Map<android.view.View, View>>(<any>listView)._realizedItems;
+            TKUnit.assertTrue(realizedItems.size <= 6, 'Realized items must be 6 or less');
+            
+            let realizedTemplates = <Map<string, Map<android.view.View, View>>>(<any>listView)._realizedTemplates; 
+            TKUnit.assertEqual(realizedTemplates.size, 3, 'Realized templates');
+            TKUnit.assertTrue(realizedTemplates.get("red").size <= 2, 'Red realized items must be 2 or less');
+            TKUnit.assertTrue(realizedTemplates.get("green").size <= 2, 'Green realized items must be 2 or less');
+            TKUnit.assertTrue(realizedTemplates.get("blue").size <= 2, 'Blue realized items must be 2 or less');
+        }
+    }
+
+    private _itemTemplatesString = `
+        <template key="red">
+            <Label text='red' style.backgroundColor='red' minHeight='100' maxHeight='100'/>
+        </template>
+        <template key='green'>
+            <Label text='green' style.backgroundColor='green' minHeight='100' maxHeight='100'/>
+        </template>
+        <template key='blue'>
+            <Label text='blue' style.backgroundColor='blue' minHeight='100' maxHeight='100'/>
+        </template>
+        `;
+    
+    private static generateItemsForMultipleTemplatesTests(count: number): Array<Item> {
+        let items = new Array<Item>();
+        for (let i = 0; i < count; i++) {
+            items.push({
+                text: "Item " + i,
+                age: i,
+                loadedCount: 0,
+                unloadedCount: 0,
+                onViewLoaded: function onViewLoaded(args) {
+                    this.loadedCount++;
+                },
+                onViewUnloaded: function onViewUnloaded(args) {
+                    this.unloadedCount++;
+                }
+            });
+        }
+        return items;
+    }
 }
 
 interface Item {
     text: string;
+    age: number;
     loadedCount: number;
     unloadedCount: number;
     onViewLoaded: (args) => void;

tns-core-modules/ui/builder/builder.d.ts

@@ -5,6 +5,7 @@
     export function load(fileName: string, exports?: any): view.View;
     export function load(options: LoadOptions): view.View;
     export function parse(value: string | view.Template, exports?: any): view.View;
+    export function parseMultipleTemplates(value: string, exports?: any): Array<view.KeyedTemplate>;
 
     export interface LoadOptions {
         path: string;

tns-core-modules/ui/builder/builder.ts

@@ -1,6 +1,6 @@
 import {debug, ScopeError, SourceError, Source} from "utils/debug";
 import * as xml from "xml";
-import {View, Template} from "ui/core/view";
+import {View, Template, KeyedTemplate} from "ui/core/view";
 import {File, path, knownFolders} from "file-system";
 import {isString, isFunction, isDefined} from "utils/types";
 import {ComponentModule, setPropertyValue, getComponentModule} from "ui/builder/component-builder";
@@ -34,11 +34,16 @@ export function parse(value: string | Template, context: any): View {
         }
 
         return viewToReturn;
-    } else if (isFunction(value)) {
+    } else if ( isFunction(value)) {
         return (<Template>value)();
     }
 }
 
+export function parseMultipleTemplates(value: string, context: any): Array<KeyedTemplate> {
+    let dummyComponent = `<ListView><ListView.itemTemplates>${value}</ListView.itemTemplates></ListView>`;
+    return parseInternal(dummyComponent, context).component["itemTemplates"];
+}
+
 function parseInternal(value: string, context: any, uri?: string): ComponentModule {
     var start: xml2ui.XmlStringParser;
     var ui: xml2ui.ComponentParser;
@@ -347,8 +352,9 @@ namespace xml2ui {
         private _state: TemplateParser.State;
 
         private parent: XmlStateConsumer;
+        private _setTemplateProperty: boolean;
 
-        constructor(parent: XmlStateConsumer, templateProperty: TemplateProperty) {
+        constructor(parent: XmlStateConsumer, templateProperty: TemplateProperty, setTemplateProperty = true) {
             this.parent = parent;
 
             this._context = templateProperty.context;
@@ -356,6 +362,7 @@ namespace xml2ui {
             this._templateProperty = templateProperty;
             this._nestingLevel = 0;
             this._state = TemplateParser.State.EXPECTING_START;
+            this._setTemplateProperty = setTemplateProperty;
         }
 
         public parse(args: xml.ParserEvent): XmlStateConsumer {
@@ -395,29 +402,64 @@ namespace xml2ui {
 
             if (this._nestingLevel === 0) {
                 this._state = TemplateParser.State.FINISHED;
-                this.build();
+                
+                if (this._setTemplateProperty && this._templateProperty.name in this._templateProperty.parent.component){
+                    let template = this._build();
+                    this._templateProperty.parent.component[this._templateProperty.name] = template;
+                }
             }
         }
 
-        private build() {
-            if (this._templateProperty.name in this._templateProperty.parent.component) {
-                var context = this._context;
-                var errorFormat = this._templateProperty.errorFormat;
-                var sourceTracker = this._templateProperty.sourceTracker;
-                var template: Template = () => {
-                    var start: xml2ui.XmlArgsReplay;
-                    var ui: xml2ui.ComponentParser;
+        public _build(): Template {
+            var context = this._context;
+            var errorFormat = this._templateProperty.errorFormat;
+            var sourceTracker = this._templateProperty.sourceTracker;
+            var template: Template = () => {
+                var start: xml2ui.XmlArgsReplay;
+                var ui: xml2ui.ComponentParser;
 
-                    (start = new xml2ui.XmlArgsReplay(this._recordedXmlStream, errorFormat))
-                        // No platform filter, it has been filtered allready
-                        .pipe(new XmlStateParser(ui = new ComponentParser(context, errorFormat, sourceTracker)));
+                (start = new xml2ui.XmlArgsReplay(this._recordedXmlStream, errorFormat))
+                    // No platform filter, it has been filtered allready
+                    .pipe(new XmlStateParser(ui = new ComponentParser(context, errorFormat, sourceTracker)));
 
-                    start.replay();
+                start.replay();
 
-                    return ui.rootComponentModule.component;
-                }
-                this._templateProperty.parent.component[this._templateProperty.name] = template;
+                return ui.rootComponentModule.component;
             }
+            return template;
+        }
+    }
+
+    export class MultiTemplateParser implements XmlStateConsumer {
+        private _childParsers = new Array<TemplateParser>();
+
+        constructor(private parent: XmlStateConsumer, private templateProperty: TemplateProperty) {
+        }
+        
+        public parse(args: xml.ParserEvent): XmlStateConsumer {
+            if (args.eventType === xml.ParserEventType.StartElement && args.elementName === "template"){
+                let childParser = new TemplateParser(this, this.templateProperty, false);
+                childParser["key"] = args.attributes["key"]; 
+                this._childParsers.push(childParser);
+                return childParser;    
+            }
+
+            if (args.eventType === xml.ParserEventType.EndElement){
+                let name = ComponentParser.getComplexPropertyName(args.elementName);
+                if (name === this.templateProperty.name){
+                    let templates = new Array<KeyedTemplate>();        
+                    for (let i = 0; i < this._childParsers.length; i++){
+                        templates.push({
+                            key: this._childParsers[i]["key"],
+                            createView: this._childParsers[i]._build()
+                        });
+                    }
+                    this.templateProperty.parent.component[this.templateProperty.name] = templates;
+                    return this.parent;
+                }
+            }
+            
+            return this;
         }
     }
 
@@ -433,6 +475,7 @@ namespace xml2ui {
 
         private static KNOWNCOLLECTIONS = "knownCollections";
         private static KNOWNTEMPLATES = "knownTemplates";
+        private static KNOWNMULTITEMPLATES = "knownMultiTemplates";
 
         public rootComponentModule: ComponentModule;
 
@@ -480,6 +523,19 @@ namespace xml2ui {
                             sourceTracker: this.sourceTracker
                         });
                     }
+                    
+                    if (ComponentParser.isKnownMultiTemplate(name, parent.exports)) {
+                        return new MultiTemplateParser(this, {
+                            context: (parent ? getExports(parent.component) : null) || this.context, // Passing 'context' won't work if you set "codeFile" on the page
+                            parent: parent,
+                            name: name,
+                            elementName: args.elementName,
+                            templateItems: [],
+                            errorFormat: this.error,
+                            sourceTracker: this.sourceTracker
+                        });
+                    }
+                    
 
                 } else {
 
@@ -550,7 +606,7 @@ namespace xml2ui {
             return isString(name) && name.indexOf(".") !== -1;
         }
 
-        private static getComplexPropertyName(fullName: string): string {
+        public static getComplexPropertyName(fullName: string): string {
             var name: string;
 
             if (isString(fullName)) {
@@ -565,6 +621,10 @@ namespace xml2ui {
             return ComponentParser.KNOWNTEMPLATES in exports && exports[ComponentParser.KNOWNTEMPLATES] && name in exports[ComponentParser.KNOWNTEMPLATES];
         }
 
+        private static isKnownMultiTemplate(name: string, exports: any): boolean {
+            return ComponentParser.KNOWNMULTITEMPLATES in exports && exports[ComponentParser.KNOWNMULTITEMPLATES] && name in exports[ComponentParser.KNOWNMULTITEMPLATES];
+        }
+
         private static addToComplexProperty(parent: ComponentModule, complexProperty: ComponentParser.ComplexProperty, elementModule: ComponentModule) {
             // If property name is known collection we populate array with elements.
             var parentComponent = <any>parent.component;

tns-core-modules/ui/builder/component-builder.ts

@@ -164,7 +164,6 @@ export function getComponentModule(elementName: string, namespace: string, attri
 
 export function setPropertyValue(instance: View, instanceModule: Object, exports: Object, propertyName: string, propertyValue: any) {
     // Note: instanceModule can be null if we are loading custom compnenet with no code-behind.
-
     if (isBinding(propertyValue) && instance.bind) {
         var bindOptions = getBindingOptions(propertyName, getBindingExpressionFromAttribute(propertyValue));
         instance.bind({
@@ -173,7 +172,8 @@ export function setPropertyValue(instance: View, instanceModule: Object, exports
             expression: bindOptions[bindingConstants.expression],
             twoWay: bindOptions[bindingConstants.twoWay]
         }, bindOptions[bindingConstants.source]);
-    } else if (isEventOrGesture(propertyName, instance)) {
+    } 
+    else if (isEventOrGesture(propertyName, instance)) {
         // Get the event handler from page module exports.
         var handler = exports && exports[propertyValue];
 
@@ -181,7 +181,11 @@ export function setPropertyValue(instance: View, instanceModule: Object, exports
         if (isFunction(handler)) {
             instance.on(propertyName, handler);
         }
-    } else {
+    }
+    else if (isKnownFunction(propertyName, instance) && isFunction(exports && exports[propertyValue])) {
+        instance[propertyName] = exports[propertyValue];             
+    }
+    else {
         let attrHandled = false;
         let specialSetter = getSpecialPropertySetter(propertyName);
         if (!attrHandled && specialSetter) {
@@ -211,3 +215,11 @@ function isBinding(value: any): boolean {
 
     return isBinding;
 }
+
+// For example, ListView.itemTemplateSelector
+let KNOWN_FUNCTIONS = "knownFunctions";
+function isKnownFunction(name: string, instance: View): boolean {
+    return instance.constructor 
+        && KNOWN_FUNCTIONS in instance.constructor 
+        && instance.constructor[KNOWN_FUNCTIONS].indexOf(name) !== -1;
+}

tns-core-modules/ui/core/view.d.ts

@@ -656,6 +656,21 @@ declare module "ui/core/view" {
         (): View;
     }
 
+    /**
+     * Defines an interface for Template with a key.
+     */
+    interface KeyedTemplate {
+        /**
+         * The unique key of the template.
+         */
+        key: string;
+
+        /**
+         * The function that creates the view.
+         */
+        createView: Template;
+    }
+
     /**
      * Defines an interface for adding arrays declared in xml.
      */

tns-core-modules/ui/list-view/list-view-common.ts

@@ -8,6 +8,8 @@ import * as builderModule from "ui/builder";
 import * as labelModule from "ui/label";
 import * as observableArrayModule from "data/observable-array";
 import * as weakEventsModule from "ui/core/weak-event-listener";
+import {isString, isFunction} from "utils/types";
+import { Bindable } from "ui/core/bindable";
 
 var builder: typeof builderModule;
 function ensureBuilder() {
@@ -39,6 +41,7 @@ function ensureWeakEvents() {
 
 var ITEMS = "items";
 var ITEMTEMPLATE = "itemTemplate";
+var ITEMTEMPLATES = "itemTemplates";
 var ISSCROLLING = "isScrolling";
 var LISTVIEW = "ListView";
 var SEPARATORCOLOR = "separatorColor";
@@ -48,6 +51,10 @@ export module knownTemplates {
     export var itemTemplate = "itemTemplate";
 }
 
+export module knownMultiTemplates {
+    export var itemTemplates = "itemTemplates";
+}
+
 function onItemsPropertyChanged(data: dependencyObservable.PropertyChangeData) {
     var listView = <ListView>data.object;
     listView._onItemsPropertyChanged(data);
@@ -58,6 +65,11 @@ function onItemTemplatePropertyChanged(data: dependencyObservable.PropertyChange
     listView.refresh();
 }
 
+function onItemTemplatesPropertyChanged(data: dependencyObservable.PropertyChangeData) {
+    var listView = <ListView>data.object;
+    listView._onItemTemplatesPropertyChanged(data);
+}
+
 function onRowHeightPropertyChanged(data: dependencyObservable.PropertyChangeData) {
     var listView = <ListView>data.object;
     listView._onRowHeightPropertyChanged(data);
@@ -67,6 +79,21 @@ export class ListView extends view.View implements definition.ListView {
     public static itemLoadingEvent = "itemLoading";
     public static itemTapEvent = "itemTap";
     public static loadMoreItemsEvent = "loadMoreItems";
+    public static knownFunctions = ["itemTemplateSelector"]; //See component-builder.ts isKnownFunction
+    
+    private _itemTemplateSelector: (item: any, index: number, items: any) => string;
+    private _itemTemplateSelectorBindable = new Bindable();
+    public _defaultTemplate: view.KeyedTemplate = {
+        key: "default",
+        createView: () => {
+            if (this.itemTemplate) {
+                ensureBuilder();
+                return builder.parse(this.itemTemplate, this); 
+            }
+            return undefined;
+        }
+    }
+    public _itemTemplatesInternal = new Array<view.KeyedTemplate>(this._defaultTemplate);
 
     public static separatorColorProperty = new dependencyObservable.Property(
         SEPARATORCOLOR,
@@ -93,6 +120,16 @@ export class ListView extends view.View implements definition.ListView {
             )
         );
 
+    public static itemTemplatesProperty = new dependencyObservable.Property(
+        ITEMTEMPLATES,
+        LISTVIEW,
+        new proxy.PropertyMetadata(
+            undefined,
+            dependencyObservable.PropertyMetadataSettings.AffectsLayout,
+            onItemTemplatesPropertyChanged
+            )
+        );
+
     public static isScrollingProperty = new dependencyObservable.Property(
         ISSCROLLING,
         LISTVIEW,
@@ -126,6 +163,40 @@ export class ListView extends view.View implements definition.ListView {
         this._setValue(ListView.itemTemplateProperty, value);
     }
 
+    get itemTemplates(): string | Array<view.KeyedTemplate> {
+        return this._getValue(ListView.itemTemplatesProperty);
+    }
+    set itemTemplates(value: string | Array<view.KeyedTemplate>) {
+        let newValue = value;
+        if (isString(newValue)){
+            ensureBuilder();
+            newValue = builder.parseMultipleTemplates(<string>newValue, this);
+        }
+        this._setValue(ListView.itemTemplatesProperty, newValue);
+    }
+
+    get itemTemplateSelector(): string | ((item: any, index: number, items: any) => string) {
+        return this._itemTemplateSelector;
+    }
+
+    set itemTemplateSelector(value: string | ((item: any, index: number, items: any) => string)) {
+        if (isString(value)){
+            this._itemTemplateSelectorBindable.bind({
+                sourceProperty: null,
+                targetProperty: "templateKey",
+                expression: <string>value
+            });
+            this._itemTemplateSelector = (item: any, index: number, items: any) => {
+                item["$index"] = index;
+                this._itemTemplateSelectorBindable.bindingContext = item;
+                return this._itemTemplateSelectorBindable.get("templateKey"); 
+            };
+        }
+        else if (isFunction(value)) {
+            this._itemTemplateSelector = <((item: any, index: number, items: any) => string)>value;
+        }
+    }
+
     get isScrolling(): boolean {
         return false;
     }
@@ -156,17 +227,23 @@ export class ListView extends view.View implements definition.ListView {
         //
     }
 
-    public _getItemTemplateContent(index: number): view.View {
-        ensureBuilder();
-
-        var v;
-        if (this.itemTemplate && this.items) {
-            v = builder.parse(this.itemTemplate, this);
+    public _getItemTemplate(index: number): view.KeyedTemplate {
+        let templateKey = "default";
+        if (this.itemTemplateSelector){
+            let dataItem = this._getDataItem(index);
+            templateKey = this._itemTemplateSelector(dataItem, index, this.items);
         }
 
-        return v;
-    }
+        for (let i = 0, length = this._itemTemplatesInternal.length; i < length; i++) {
+            if (this._itemTemplatesInternal[i].key === templateKey){
+                return this._itemTemplatesInternal[i];
+            }
+        }
 
+        // This is the default template
+        return this._itemTemplatesInternal[0]; 
+    }
+    
     public _prepareItem(item: view.View, index: number) {
         if (item) {
             item.bindingContext = this._getDataItem(index);
@@ -211,4 +288,8 @@ export class ListView extends view.View implements definition.ListView {
     public _onRowHeightPropertyChanged(data: dependencyObservable.PropertyChangeData) {
         this.refresh();
     }
+
+    public _onItemTemplatesPropertyChanged(data: dependencyObservable.PropertyChangeData) {
+        //
+    }
 }

tns-core-modules/ui/list-view/list-view.android.ts

@@ -42,7 +42,8 @@ function onSeparatorColorPropertyChanged(data: dependencyObservable.PropertyChan
 export class ListView extends common.ListView {
     private _androidViewId: number = -1;
     private _android: android.widget.ListView;
-    public _realizedItems = new Map<android.view.View, viewModule.View>();
+    public _realizedItems = new Map<android.view.View, viewModule.View>();    
+    public _realizedTemplates = new Map<string, Map<android.view.View, viewModule.View>>();
 
     public _createUI() {
         this._android = new android.widget.ListView(this._context);
@@ -62,7 +63,8 @@ export class ListView extends common.ListView {
             onItemClick: function (parent: any, convertView: android.view.View, index: number, id: number) {
                 let owner = that.get();
                 if (owner) {
-                    owner.notify({ eventName: ITEMTAP, object: owner, index: index, view: owner._getRealizedView(convertView, index) });
+                    let view = owner._realizedTemplates.get(owner._getItemTemplate(index).key).get(convertView);
+                    owner.notify({ eventName: ITEMTAP, object: owner, index: index, view: view });
                 }
             }
         }));
@@ -83,7 +85,7 @@ export class ListView extends common.ListView {
                 view.bindingContext = null;
             }
         });
-
+        
         (<android.widget.BaseAdapter>this.android.getAdapter()).notifyDataSetChanged();
     }
 
@@ -116,13 +118,16 @@ export class ListView extends common.ListView {
         });
     }
 
-    public _getRealizedView(convertView: android.view.View, index: number) {
-        if (!convertView) {
-            return this._getItemTemplateContent(index);
-        }
-
-        return this._realizedItems.get(convertView);
-    }
+    public _dumpRealizedTemplates(){
+        console.log(`Realized Templates:`);    
+        this._realizedTemplates.forEach((value, index, map) => {
+            console.log(`\t${index}:`);
+            value.forEach((value, index, map) => {
+                console.log(`\t\t${index.hashCode()}: ${value}`);
+            });
+        });
+        console.log(`Realized Items Size: ${this._realizedItems.size}`);    
+    } 
 
     private clearRealizedCells(): void {
         // clear the cache
@@ -137,6 +142,21 @@ export class ListView extends common.ListView {
         });
 
         this._realizedItems.clear();
+        this._realizedTemplates.clear();
+    }
+
+    public _onItemTemplatesPropertyChanged(data: dependencyObservable.PropertyChangeData) {
+        this._itemTemplatesInternal = new Array<viewModule.KeyedTemplate>(this._defaultTemplate); 
+        if (data.newValue){
+            this._itemTemplatesInternal = this._itemTemplatesInternal.concat(data.newValue);
+        }
+        
+        if (this.android){
+            ensureListViewAdapterClass();
+            this.android.setAdapter(new ListViewAdapterClass(this));
+        }
+        
+        this.refresh();
     }
 }
 
@@ -177,7 +197,19 @@ function ensureListViewAdapterClass() {
             return true;
         }
 
+        public getViewTypeCount() {
+            return this._listView._itemTemplatesInternal.length; 
+        }
+
+        public getItemViewType(index: number) {
+            let template = this._listView._getItemTemplate(index);
+            let itemViewType = this._listView._itemTemplatesInternal.indexOf(template);
+            return itemViewType;
+        }
+        
         public getView(index: number, convertView: android.view.View, parent: android.view.ViewGroup): android.view.View {
+            //this._listView._dumpRealizedTemplates();
+            
             if (!this._listView) {
                 return null;
             }
@@ -187,7 +219,19 @@ function ensureListViewAdapterClass() {
                 this._listView.notify({ eventName: LOADMOREITEMS, object: this._listView });
             }
 
-            let view = this._listView._getRealizedView(convertView, index);
+            // Recycle an existing view or create a new one if needed.
+            let template = this._listView._getItemTemplate(index);
+            let view: viewModule.View;
+            if (convertView){
+                view = this._listView._realizedTemplates.get(template.key).get(convertView);
+                if (!view){
+                    throw new Error(`There is no entry with key '${convertView}' in the realized views cache for template with key'${template.key}'.`);
+                }
+            }
+            else {
+                view = template.createView();
+            }
+
             let args: definition.ItemEventData = {
                 eventName: ITEMLOADING, object: this._listView, index: index, view: view,
                 android: parent,
@@ -225,6 +269,13 @@ function ensureListViewAdapterClass() {
                     }
                 }
 
+                // Cache the view for recycling
+                let realizedItemsForTemplateKey = this._listView._realizedTemplates.get(template.key);
+                if (!realizedItemsForTemplateKey){
+                    realizedItemsForTemplateKey = new Map<android.view.View, viewModule.View>();
+                    this._listView._realizedTemplates.set(template.key, realizedItemsForTemplateKey);
+                } 
+                realizedItemsForTemplateKey.set(convertView, args.view);
                 this._listView._realizedItems.set(convertView, args.view);
             }
 

tns-core-modules/ui/list-view/list-view.d.ts

@@ -82,6 +82,16 @@ declare module "ui/list-view" {
          */
         itemTemplate: string | view.Template;
 
+        /**
+         * Gets or set the list of item templates for the item template selector 
+         */
+        itemTemplates: string | Array<view.KeyedTemplate>;
+
+        /**
+         * A function that returns the appropriate ket template based on the data item.
+         */
+
+        itemTemplateSelector: string | ((item: any, index: number, items: any) => string);
         /**
          * Gets or set the items separator line color of the ListView. 
          */

tns-core-modules/ui/list-view/list-view.ios.ts

@@ -16,7 +16,7 @@ function ensureColor() {
     }
 }
 
-var CELLIDENTIFIER = "cell";
+//var CELLIDENTIFIER = "cell";
 var ITEMLOADING = common.ListView.itemLoadingEvent;
 var LOADMOREITEMS = common.ListView.loadMoreItemsEvent;
 var ITEMTAP = common.ListView.itemTapEvent;
@@ -68,9 +68,11 @@ class DataSource extends NSObject implements UITableViewDataSource {
 
     public tableViewCellForRowAtIndexPath(tableView: UITableView, indexPath: NSIndexPath): UITableViewCell {
         // We call this method because ...ForIndexPath calls tableViewHeightForRowAtIndexPath immediately (before we can prepare and measure it).
-        let cell = <ListViewCell>(tableView.dequeueReusableCellWithIdentifier(CELLIDENTIFIER) || ListViewCell.new());
         let owner = this._owner.get();
+        let cell: ListViewCell;
         if (owner) {
+            let template = owner._getItemTemplate(indexPath.row);
+            cell = <ListViewCell>(tableView.dequeueReusableCellWithIdentifier(template.key) || ListViewCell.new());
             owner._prepareCell(cell, indexPath);
 
             let cellView: view.View = cell.view;
@@ -83,6 +85,9 @@ class DataSource extends NSObject implements UITableViewDataSource {
                 view.View.layoutChild(owner, cellView, 0, 0, width, cellHeight);
             }
         }
+        else {
+            cell = <ListViewCell>ListViewCell.new();
+        }
         return cell;
     }
 }
@@ -91,11 +96,13 @@ class UITableViewDelegateImpl extends NSObject implements UITableViewDelegate {
     public static ObjCProtocols = [UITableViewDelegate];
 
     private _owner: WeakRef<ListView>;
-    private _measureCell: ListViewCell;
+    
+    private _measureCellMap: Map<string, ListViewCell>;
 
     public static initWithOwner(owner: WeakRef<ListView>): UITableViewDelegateImpl {
         let delegate = <UITableViewDelegateImpl>UITableViewDelegateImpl.new();
         delegate._owner = owner;
+        delegate._measureCellMap = new Map<string, ListViewCell>();
         return delegate;
     }
 
@@ -134,10 +141,11 @@ class UITableViewDelegateImpl extends NSObject implements UITableViewDelegate {
 
         if (utils.ios.MajorVersion < 8 || height === undefined) {
             // in iOS 7.1 (or iOS8+ after call to scrollToRowAtIndexPath:atScrollPosition:animated:) this method is called before tableViewCellForRowAtIndexPath so we need fake cell to measure its content.
-            let cell = this._measureCell;
+            let template = owner._getItemTemplate(indexPath.row);
+            let cell = this._measureCellMap.get(template.key);
             if (!cell) {
-                this._measureCell = (<any>tableView.dequeueReusableCellWithIdentifier(CELLIDENTIFIER)) || ListViewCell.new();
-                cell = this._measureCell;
+                cell = (<any>tableView.dequeueReusableCellWithIdentifier(template.key)) || ListViewCell.new();
+                this._measureCellMap.set(template.key, cell);
             }
 
             height = owner._prepareCell(cell, indexPath);
@@ -214,7 +222,7 @@ export class ListView extends common.ListView {
     constructor() {
         super();
         this._ios = UITableView.new();
-        this._ios.registerClassForCellReuseIdentifier(ListViewCell.class(), CELLIDENTIFIER);
+        this._ios.registerClassForCellReuseIdentifier(ListViewCell.class(), this._defaultTemplate.key);
         this._ios.autoresizingMask = UIViewAutoresizing.None;
         this._ios.estimatedRowHeight = DEFAULT_HEIGHT;
         this._ios.rowHeight = UITableViewAutomaticDimension;
@@ -224,6 +232,18 @@ export class ListView extends common.ListView {
         this._map = new Map<ListViewCell, view.View>();
     }
 
+    public _onItemTemplatesPropertyChanged(data: dependencyObservable.PropertyChangeData) {
+        this._itemTemplatesInternal = new Array<view.KeyedTemplate>(this._defaultTemplate); 
+        if (data.newValue) {
+            for(let i = 0, length = data.newValue.length; i < length; i++){
+                let template = <view.KeyedTemplate>data.newValue[i];
+                this._ios.registerClassForCellReuseIdentifier(ListViewCell.class(), template.key);
+            }
+            this._itemTemplatesInternal = this._itemTemplatesInternal.concat(data.newValue);
+        }
+        this.refresh();
+    }
+
     public onLoaded() {
         super.onLoaded();
         if (this._isDataDirty) {
@@ -336,7 +356,7 @@ export class ListView extends common.ListView {
             this._preparingCell = true;
             let view = cell.view;
             if (!view) {
-                view = this._getItemTemplateContent(indexPath.row);
+                view = this._getItemTemplate(indexPath.row).createView();
             }
 
             let args = notifyForItemAtIndex(this, cell, view, ITEMLOADING, indexPath);