Add chips keyboard support.

Add basic focus/keyboard support for chips.

 - Up/down arrows navigate chips.
 - Clicking a chip properly focuses it for subsequent keyboard
   navigation.
 - More demos.

References angular#120.

src/demo-app/chips/chips-demo.html

@@ -2,11 +2,67 @@
   <section>
     <h3>Static Chips</h3>
 
+    <h5>Simple</h5>
+
+    <md-chip-list>
+      <md-chip>Chip 1</md-chip>
+      <md-chip>Chip 2</md-chip>
+      <md-chip>Chip 3</md-chip>
+    </md-chip-list>
+
+    <h5>Advanced</h5>
+
+    <md-chip-list>
+      <md-chip class="md-accent selected">Selected/Colored</md-chip>
+      <md-chip class="md-warn" *ngIf="visible"
+               (destroy)="alert('chip destroyed')" (click)="toggleVisible()">
+        With Events
+      </md-chip>
+    </md-chip-list>
+
+    <h5>Unstyled</h5>
+
+    <md-chip-list>
+      <md-basic-chip>Basic Chip 1</md-basic-chip>
+      <md-basic-chip>Basic Chip 2</md-basic-chip>
+      <md-basic-chip>Basic Chip 3</md-basic-chip>
+    </md-chip-list>
+
+    <h3>Material Contributors</h3>
+
     <md-chip-list>
-      <md-chip>Basic Chip</md-chip>
-      <md-chip class="selected md-primary">Primary</md-chip>
-      <md-chip class="selected md-accent">Accent</md-chip>
-      <md-chip class="selected md-warn">Warn</md-chip>
+      <md-chip *ngFor="let person of people; let even = even" [ngClass]="[color, even ? 'selected' : '' ]">
+        {{person.name}}
+      </md-chip>
+    </md-chip-list>
+
+    <br />
+
+    <md-input #input (keyup.enter)="add(input)" (blur)="add(input)" placeholder="New Contributor...">
+    </md-input>
+
+    <h3>Stacked Chips</h3>
+
+    <p>
+      You can also stack the chips if you want them on top of each other.
+    </p>
+
+    <md-chip-list class="md-chip-list-stacked">
+      <md-chip (didfocus)="color = ''" class="selected">
+        None
+      </md-chip>
+
+      <md-chip (didfocus)="color = 'md-primary'" class="selected md-primary">
+        Primary
+      </md-chip>
+
+      <md-chip (didfocus)="color = 'md-accent'" class="selected md-accent">
+        Accent
+      </md-chip>
+
+      <md-chip (didfocus)="color = 'md-warn'" class="selected md-warn">
+        Warn
+      </md-chip>
     </md-chip-list>
   </section>
 </div>

src/demo-app/chips/chips-demo.scss

@@ -1,2 +1,10 @@
 .chips-demo {
+  .md-chip-list-stacked {
+    display: block;
+    max-width: 200px;
+  }
+
+  md-basic-chip {
+    margin: auto 10px;
+  }
 }

src/demo-app/chips/chips-demo.ts

@@ -1,10 +1,41 @@
 import {Component} from '@angular/core';
 
+export interface Person {
+  name: string;
+}
+
 @Component({
   moduleId: module.id,
   selector: 'chips-demo',
   templateUrl: 'chips-demo.html',
   styleUrls: ['chips-demo.css']
 })
 export class ChipsDemo {
+  visible: boolean = true;
+  color: string = '';
+
+  people: Person[] = [
+    { name: 'Kara' },
+    { name: 'Jeremy' },
+    { name: 'Topher' },
+    { name: 'Elad' },
+    { name: 'Kristiyan' },
+    { name: 'Paul' }
+  ];
+  favorites: Person[] = [];
+
+  alert(message: string): void {
+    alert(message);
+  }
+
+  add(input: HTMLInputElement): void {
+    if (input.value && input.value.trim() != '') {
+      this.people.push({ name: input.value.trim() });
+      input.value = '';
+    }
+  }
+
+  toggleVisible(): void {
+    this.visible = false;
+  }
 }

src/lib/chips/_chips-theme.scss

@@ -13,6 +13,10 @@
   }
 
   .md-chip.selected {
+    // TODO: Based on spec, this should be #808080, but we can only use md-contrast with a palette
+    background-color: md-color($md-grey, 600);
+    color: md-contrast($md-grey, 600);
+
     &.md-primary {
       background-color: md-color($primary, 500);
       color: md-contrast($primary, 500);
@@ -26,4 +30,4 @@
       color: md-contrast($warn, 500);
     }
   }
-}
+}

src/lib/chips/chip-list-key-manager.spec.ts

@@ -0,0 +1,79 @@
+import {QueryList} from '@angular/core';
+import {async, TestBed} from '@angular/core/testing';
+import {MdBasicChip} from './index';
+import {ChipListKeyManager} from './chip-list-key-manager';
+
+class FakeChip extends MdBasicChip {
+  constructor() {
+    // Pass in null for the renderer/elementRef
+    super(null, null);
+  }
+
+  // Override the focus() method to NOT call the underlying renderer (which is null)
+  focus() {
+    this.didfocus.emit();
+  }
+}
+
+describe('ChipListKeyManager', () => {
+  let items: QueryList<MdBasicChip>;
+  let manager: ChipListKeyManager;
+
+  beforeEach(async(() => {
+    items = new QueryList<MdBasicChip>();
+    items.reset([
+      new FakeChip(),
+      new FakeChip(),
+      new FakeChip(),
+      new FakeChip(),
+      new FakeChip()
+    ]);
+
+    manager = new ChipListKeyManager(items);
+
+    TestBed.compileComponents();
+  }));
+
+  describe('basic behaviors', () => {
+    it('watches for chip focus', () => {
+      let array = items.toArray();
+      let lastIndex = array.length - 1;
+      let lastItem = array[lastIndex];
+
+      lastItem.focus();
+
+      expect(manager.focusedItemIndex).toBe(lastIndex);
+    });
+
+    describe('on chip destroy', () => {
+      it('focuses the next item', () => {
+        let array = items.toArray();
+        let midItem = array[2];
+
+        // Focus the middle item
+        midItem.focus();
+
+        // Destroy the middle item
+        midItem.destroy.emit();
+
+        // It focuses the 4th item (now at index 2)
+        expect(manager.focusedItemIndex).toEqual(2);
+      });
+
+      it('focuses the previous item', () => {
+        let array = items.toArray();
+        let lastIndex = array.length - 1;
+        let lastItem = array[lastIndex];
+
+        // Focus the last item
+        lastItem.focus();
+
+        // Destroy the last item
+        lastItem.destroy.emit();
+
+        // It focuses the next-to-last item
+        expect(manager.focusedItemIndex).toEqual(lastIndex - 1);
+      });
+    });
+  });
+});

src/lib/chips/chip-list-key-manager.ts

@@ -0,0 +1,89 @@
+import {QueryList} from '@angular/core';
+import {ListKeyManager} from '../core/a11y/list-key-manager';
+import {MdBasicChip} from './chip';
+
+/**
+ * Manages keyboard events for the chip list and its chips. When instantiated
+ * with a QueryList of MdBasicChip (i.e. any chip), it will ensure focus and
+ * keyboard navigation are properly handled.
+ */
+export class ChipListKeyManager extends ListKeyManager {
+  private _subscribed: MdBasicChip[] = [];
+
+  constructor(private _chips: QueryList<MdBasicChip>) {
+    super(_chips);
+
+    // Go ahead and subscribe all of the initial chips
+    this.subscribeChips(this._chips);
+
+    // When the list changes, re-subscribe
+    this._chips.changes.subscribe((chips: QueryList<MdBasicChip>) => {
+      this.subscribeChips(chips);
+    });
+  }
+
+  /**
+   * Iterate through the list of chips and add them to our list of
+   * subscribed chips.
+   *
+   * @param chips The list of chips to be subscribed.
+   */
+  protected subscribeChips(chips: QueryList<MdBasicChip>): void {
+    chips.forEach((chip: MdBasicChip) => {
+      this.addChip(chip);
+    });
+  }
+
+  /**
+   * Add a specific chip to our subscribed list. If the chip has
+   * already been subscribed, this ensures it is only subscribed
+   * once.
+   *
+   * @param chip The chip to be subscribed (or checked for existing
+   * subscription).
+   */
+  protected addChip(chip: MdBasicChip) {
+    // If we've already been subscribed to a parent, do nothing
+    if (this._subscribed.indexOf(chip) > -1) {
+      return;
+    }
+
+    // Watch for focus events outside of the keyboard navigation
+    chip.didfocus.subscribe(() => {
+      let chipIndex: number = this._chips.toArray().indexOf(chip);
+
+      if (this.isValidIndex(chipIndex)) {
+        this.setFocus(chipIndex, false);
+      }
+    });
+
+    // On destroy, remove the item from our list, and check focus
+    chip.destroy.subscribe(() => {
+      let chipIndex: number = this._chips.toArray().indexOf(chip);
+
+      if (this.isValidIndex(chipIndex)) {
+        //
+        if (chipIndex < this._chips.length - 1) {
+          this.setFocus(chipIndex);
+        } else if (chipIndex - 1 >= 0) {
+          this.setFocus(chipIndex - 1);
+        }
+      }
+
+      this._subscribed.splice(this._subscribed.indexOf(chip), 1);
+      chip.destroy.unsubscribe();
+    });
+
+    this._subscribed.push(chip);
+  }
+
+  /**
+   * Utility to ensure all indexes are valid.
+   *
+   * @param index The index to be checked.
+   * @returns {boolean} True if the index is valid for our list of chips.
+   */
+  private isValidIndex(index: number): boolean {
+    return index >= 0 && index < this._chips.length;
+  }
+}