feat(radio): support ngModel on md-radio-group

Closes #209

src/components/radio/README.md

@@ -21,6 +21,15 @@ A dynamic example, populated from a `data` variable:
 </md-radio-group>
 ```
 
+A dynamic example for use inside a form showing support for `[(ngModel)]`:
+```html
+<md-radio-group [(ngModel)]="chosenOption">
+  <md-radio-button *ngFor="#o of options" [value]="o.value">
+    {{o.label}}
+  </md-radio-button>
+</md-radio-group>
+```
+
 ## `<md-radio-group>`
 ### Properties
 

src/components/radio/radio.spec.ts

@@ -258,6 +258,68 @@ export function main() {
           });
         }).then(done);
     });
+
+    it('should bind value to model without initial value', (done: () => void) => {
+      builder
+        .overrideTemplate(TestApp, `
+            <md-radio-group  [(ngModel)]="choice">
+              <md-radio-button [value]="0"></md-radio-button>
+              <md-radio-button [value]="1"></md-radio-button>
+            </md-radio-group>`)
+        .createAsync(TestApp)
+        .then((fixture) => {
+          fakeAsync(function() {
+            let buttons = fixture.debugElement.queryAll(By.css('md-radio-button'));
+            let group = fixture.debugElement.query(By.css('md-radio-group'));
+
+            fixture.detectChanges();
+            expect(buttons[0].componentInstance.checked).toBe(false);
+            expect(buttons[1].componentInstance.checked).toBe(false);
+            expect(fixture.componentInstance.choice).toBe(undefined);
+
+            group.componentInstance.selected = buttons[0].componentInstance;
+            fixture.detectChanges();
+            expect(isSinglySelected(buttons[0], buttons)).toBe(true);
+            expect(fixture.componentInstance.choice).toBe(0);
+
+            group.componentInstance.selected = buttons[1].componentInstance;
+            fixture.detectChanges();
+            expect(isSinglySelected(buttons[1], buttons)).toBe(true);
+            expect(fixture.componentInstance.choice).toBe(1);
+          });
+        }).then(done);
+    });
+
+    it('should bind value to model with initial value', (done: () => void) => {
+      builder
+        .overrideTemplate(TestAppWithInitialValue, `
+            <md-radio-group  [(ngModel)]="choice">
+              <md-radio-button [value]="0"></md-radio-button>
+              <md-radio-button [value]="1"></md-radio-button>
+            </md-radio-group>`)
+        .createAsync(TestAppWithInitialValue)
+        .then((fixture) => {
+          fakeAsync(function() {
+            let buttons = fixture.debugElement.queryAll(By.css('md-radio-button'));
+            let group = fixture.debugElement.query(By.css('md-radio-group'));
+
+            fixture.detectChanges();
+            expect(isSinglySelected(buttons[1], buttons)).toBe(true);
+            expect(fixture.componentInstance.choice).toBe(1);
+
+            group.componentInstance.selected = buttons[0].componentInstance;
+            fixture.detectChanges();
+            expect(isSinglySelected(buttons[0], buttons)).toBe(true);
+            expect(fixture.componentInstance.choice).toBe(0);
+
+            group.componentInstance.selected = buttons[1].componentInstance;
+            fixture.detectChanges();
+            expect(isSinglySelected(buttons[1], buttons)).toBe(true);
+            expect(fixture.componentInstance.choice).toBe(1);
+          });
+        }).then(done);
+    });
+
   });
 }
 
@@ -289,4 +351,16 @@ function createEvent(name: string): Event {
   providers: [MdRadioDispatcher],
   template: ''
 })
-class TestApp {}
+class TestApp {
+  choice: number;
+}
+
+/** Test component. */
+@Component({
+  directives: [MdRadioButton, MdRadioGroup],
+  providers: [MdRadioDispatcher],
+  template: ''
+})
+class TestAppWithInitialValue {
+  choice: number = 1;
+}

src/components/radio/radio.ts

@@ -10,14 +10,31 @@ import {
   OnInit,
   Optional,
   Output,
+  Provider,
   QueryList,
   ViewEncapsulation,
   forwardRef
 } from 'angular2/core';
 
+import {
+  NG_VALUE_ACCESSOR,
+  ControlValueAccessor
+} from 'angular2/src/common/forms/directives/control_value_accessor';
+import {CONST_EXPR} from 'angular2/src/facade/lang';
+
 import {MdRadioDispatcher} from './radio_dispatcher';
 export {MdRadioDispatcher} from './radio_dispatcher';
 
+/**
+ * Provider Expression that allows md-radio-group to register as a ControlValueAccessor. This
+ * allows it to support [(ngModel)] and ngControl.
+ */
+const MD_RADIO_GROUP_CONTROL_VALUE_ACCESSOR = CONST_EXPR(new Provider(
+    NG_VALUE_ACCESSOR, {
+      useExisting: forwardRef(() => MdRadioGroup),
+      multi: true
+    }));
+
 // TODO(mtlin):
 // Ink ripple is currently placeholder.
 // Determine motion spec for button transitions.
@@ -36,11 +53,12 @@ export class MdRadioChange {
 
 @Directive({
   selector: 'md-radio-group',
+  providers: [MD_RADIO_GROUP_CONTROL_VALUE_ACCESSOR],
   host: {
     'role': 'radiogroup',
   },
 })
-export class MdRadioGroup implements AfterContentInit {
+export class MdRadioGroup implements AfterContentInit, ControlValueAccessor {
   /** The value for the radio group. Should match currently selected button. */
   private _value: any = null;
 
@@ -53,6 +71,11 @@ export class MdRadioGroup implements AfterContentInit {
   /** The currently selected radio button. Should match value. */
   private _selected: MdRadioButton = null;
 
+  /** Change event subscription set up by registerOnChange (ControlValueAccessor). */
+  private _changeSubscription: {unsubscribe: () => any} = null;
+
+  onTouched: () => any = () => {};
+
   /** Event emitted when the group value changes. */
   @Output()
   change: EventEmitter<MdRadioChange> = new EventEmitter();
@@ -155,6 +178,25 @@ export class MdRadioGroup implements AfterContentInit {
 
     selected.checked = true;
   }
+
+   /** Implemented as part of ControlValueAccessor. */
+  writeValue(value: any) {
+    this.value = value;
+  }
+
+  /** Implemented as part of ControlValueAccessor. */
+  registerOnChange(fn: any) {
+    if (this._changeSubscription) {
+      this._changeSubscription.unsubscribe();
+    }
+    this._changeSubscription = <{unsubscribe: () => any}>this.change.subscribe(
+      (changeEvent: MdRadioChange) => { fn(changeEvent.value); });
+  }
+
+  /** Implemented as part of ControlValueAccessor. */
+  registerOnTouched(fn: any) {
+    this.onTouched = fn;
+  }
 }
 
 
@@ -210,6 +252,10 @@ export class MdRadioButton implements OnInit {
     if (this.id == null) {
       this.id = `md-radio-${_uniqueIdCounter++}`;
     }
+
+    if (this.radioGroup && this._value == this.radioGroup.value) {
+      this._checked = true;
+    }
   }
 
   /*

src/demo-app/radio/radio-demo.html

@@ -1,8 +1,10 @@
+<h1>Basic Example</h1>
 <section class="demo-section">
   <md-radio-button name="group1">Option 1</md-radio-button>
   <md-radio-button name="group1">Option 2</md-radio-button>
   <md-radio-button name="group1" disabled="true">Option 3 (disabled)</md-radio-button>
 </section>
+<h1>Dynamic Example</h1>
 <section class="demo-section">
   <div>
     <span>isDisabled: {{isDisabled}}</span>
@@ -16,3 +18,13 @@
     <md-radio-button value="option_3">Option 3</md-radio-button>
   </md-radio-group>
 </section>
+<h1>Favorite Season Example</h1>
+<h2>Dynamic Example with two-way data-binding</h2>
+<section class="demo-section">
+  <md-radio-group name="more_options" [(ngModel)]="favoriteSeason">
+    <md-radio-button *ngFor="#season of seasonOptions" name="more_options" [value]="season">
+      {{season}}
+    </md-radio-button>
+  </md-radio-group>
+  <p>Your favorite season is: {{favoriteSeason}}</p>
+</section>

src/demo-app/radio/radio-demo.ts

@@ -11,4 +11,11 @@ import {MdRadioDispatcher} from '../../components/radio/radio_dispatcher';
 })
 export class RadioDemo {
   isDisabled: boolean = false;
+  favoriteSeason: string = 'Autumn';
+  seasonOptions = [
+    'Winter',
+    'Spring',
+    'Summer',
+    'Autumn',
+  ];
 }