feat(snack bar): Add enter and exit animations. (#1320)

* feat(md-snack-bar): Create initial MdSnackBar.

* Add enter and exit animation to MdSnackBar.

* feat(md-snack-bar): Create initial MdSnackBar.

* feat(md-snack-bar): Create initial MdSnackBar.

* Add enter and exit animation to MdSnackBar.

src/lib/core/animation/animation.ts

@@ -0,0 +1,13 @@
+export class AnimationCurves {
+  static STANDARD_CURVE = 'cubic-bezier(0.4,0.0,0.2,1)';
+  static DECELERATION_CURVE = 'cubic-bezier(0.0,0.0,0.2,1)';
+  static ACCELERATION_CURVE = 'cubic-bezier(0.4,0.0,1,1)';
+  static SHARP_CURVE = 'cubic-bezier(0.4,0.0,0.6,1)';
+};
+
+
+export class AnimationDurations {
+   static COMPLEX = '375ms';
+   static ENTERING = '225ms';
+   static EXITING = '195ms';
+ };

src/lib/core/core.ts

@@ -79,6 +79,9 @@ export {ComponentType} from './overlay/generic-component-type';
 // Keybindings
 export * from './keyboard/keycodes';
 
+// Animation
+export * from './animation/animation';
+
 
 @NgModule({
   imports: [MdLineModule, RtlModule, MdRippleModule, PortalModule, OverlayModule, A11yModule],

src/lib/snack-bar/snack-bar-container.scss

@@ -10,11 +10,13 @@ $md-snack-bar-max-width: 568px !default;
   @include md-elevation(24);
   background: #323232;
   border-radius: 2px;
+  box-sizing: content-box;
   display: block;
   height: $md-snack-bar-height;
   max-width: $md-snack-bar-max-width;
   min-width: $md-snack-bar-min-width;
   overflow: hidden;
   padding: $md-snack-bar-padding;
-  box-sizing: content-box;
+  // Initial transformation is applied to start snack bar out of view.
+  transform: translateY(100%);
 }

src/lib/snack-bar/snack-bar-container.ts

@@ -1,18 +1,32 @@
 import {
   Component,
   ComponentRef,
-  ViewChild
+  ViewChild,
+  trigger,
+  state,
+  style,
+  transition,
+  animate,
+  AnimationTransitionEvent,
+  NgZone
 } from '@angular/core';
 import {
   BasePortalHost,
   ComponentPortal,
   TemplatePortal,
-  PortalHostDirective
+  PortalHostDirective,
+  AnimationCurves,
+  AnimationDurations,
 } from '../core';
 import {MdSnackBarConfig} from './snack-bar-config';
 import {MdSnackBarContentAlreadyAttached} from './snack-bar-errors';
+import {Observable} from 'rxjs/Observable';
+import {Subject} from 'rxjs/Subject';
 
 
+
+export type SnackBarState = 'initial' | 'visible' | 'complete' | 'void';
+
 /**
  * Internal component that wraps user-provided snack bar content.
  */
@@ -22,17 +36,40 @@ import {MdSnackBarContentAlreadyAttached} from './snack-bar-errors';
   templateUrl: 'snack-bar-container.html',
   styleUrls: ['snack-bar-container.css'],
   host: {
-    'role': 'alert'
-  }
+    'role': 'alert',
+    '[@state]': 'animationState',
+    '(@state.done)': 'markAsExited($event)'
+  },
+  animations: [
+    trigger('state', [
+      state('initial', style({transform: 'translateY(100%)'})),
+      state('visible', style({transform: 'translateY(0%)'})),
+      state('complete', style({transform: 'translateY(100%)'})),
+      transition('visible => complete',
+                 animate(`${AnimationDurations.EXITING} ${AnimationCurves.DECELERATION_CURVE}`)),
+      transition('initial => visible, void => visible',
+                 animate(`${AnimationDurations.ENTERING} ${AnimationCurves.ACCELERATION_CURVE}`)),
+    ])
+  ],
 })
 export class MdSnackBarContainer extends BasePortalHost {
   /** The portal host inside of this container into which the snack bar content will be loaded. */
   @ViewChild(PortalHostDirective) _portalHost: PortalHostDirective;
 
+  /** Subject for notifying that the snack bar has exited from view. */
+  private _onExit: Subject<any> = new Subject();
+
+  /** The state of the snack bar animations. */
+  animationState: SnackBarState = 'initial';
+
   /** The snack bar configuration. */
   snackBarConfig: MdSnackBarConfig;
 
-  /** Attach a portal as content to this snack bar container. */
+  constructor(private _ngZone: NgZone) {
+    super();
+  }
+
+  /** Attach a component portal as content to this snack bar container. */
   attachComponentPortal<T>(portal: ComponentPortal<T>): ComponentRef<T> {
     if (this._portalHost.hasAttached()) {
       throw new MdSnackBarContentAlreadyAttached();
@@ -41,7 +78,30 @@ export class MdSnackBarContainer extends BasePortalHost {
     return this._portalHost.attachComponentPortal(portal);
   }
 
+  /** Attach a template portal as content to this snack bar container. */
   attachTemplatePortal(portal: TemplatePortal): Map<string, any> {
     throw Error('Not yet implemented');
   }
+
+  /** Begin animation of the snack bar exiting from view. */
+  exit(): Observable<void> {
+    this.animationState = 'complete';
+    return this._onExit.asObservable();
+  }
+
+  /** Mark snack bar as exited from the view. */
+  markAsExited(event: AnimationTransitionEvent) {
+    if (event.fromState === 'visible' &&
+        (event.toState === 'void' || event.toState === 'complete')) {
+      this._ngZone.run(() => {
+        this._onExit.next();
+        this._onExit.complete();
+      });
+    }
+  }
+
+  /** Begin animation of snack bar entrance into view. */
+  enter(): void {
+    this.animationState = 'visible';
+  }
 }

src/lib/snack-bar/snack-bar-ref.ts

@@ -1,6 +1,7 @@
 import {OverlayRef} from '../core';
 import {Observable} from 'rxjs/Observable';
 import {Subject} from 'rxjs/Subject';
+import {MdSnackBarContainer} from './snack-bar-container';
 
 // TODO(josephperrott): Implement onAction observable.
 
@@ -12,19 +13,28 @@ export class MdSnackBarRef<T> {
   /** The instance of the component making up the content of the snack bar. */
   readonly instance: T;
 
+  /** The instance of the component making up the content of the snack bar. */
+  readonly containerInstance: MdSnackBarContainer;
+
   /** Subject for notifying the user that the snack bar has closed. */
   private _afterClosed: Subject<any> = new Subject();
 
-  constructor(instance: T, private _overlayRef: OverlayRef) {
+  constructor(instance: T,
+              containerInstance: MdSnackBarContainer,
+              private _overlayRef: OverlayRef) {
     // Sets the readonly instance of the snack bar content component.
     this.instance = instance;
+    this.containerInstance = containerInstance;
   }
 
   /** Dismisses the snack bar. */
   dismiss(): void {
     if (!this._afterClosed.closed) {
-      this._overlayRef.dispose();
-      this._afterClosed.complete();
+      this.containerInstance.exit().subscribe(() => {
+        this._overlayRef.dispose();
+        this._afterClosed.next();
+        this._afterClosed.complete();
+      });
     }
   }
 

src/lib/snack-bar/snack-bar.spec.ts

@@ -16,6 +16,7 @@ import {OverlayContainer} from '../core';
 import {MdSnackBarConfig} from './snack-bar-config';
 import {SimpleSnackBar} from './simple-snack-bar';
 
+// TODO(josephperrott): Update tests to mock waiting for time to complete for animations.
 
 describe('MdSnackBar', () => {
   let snackBar: MdSnackBar;
@@ -56,7 +57,6 @@ describe('MdSnackBar', () => {
     snackBar.open(simpleMessage, simpleActionLabel, config);
 
     let containerElement = overlayContainerElement.querySelector('snack-bar-container');
-
     expect(containerElement.getAttribute('role'))
         .toBe('alert', 'Expected snack bar container to have role="alert"');
    });
@@ -102,7 +102,6 @@ describe('MdSnackBar', () => {
     expect(messageElement.tagName).toBe('SPAN', 'Expected snack bar message element to be <span>');
     expect(messageElement.textContent)
         .toBe(simpleMessage, `Expected the snack bar message to be '${simpleMessage}''`);
-
     expect(overlayContainerElement.querySelector('button.md-simple-snackbar-action'))
         .toBeNull('Expected the query selection for action label to be null');
   });
@@ -120,10 +119,11 @@ describe('MdSnackBar', () => {
         .toBeGreaterThan(0, 'Expected overlay container element to have at least one child');
 
     snackBarRef.dismiss();
-
-    expect(dismissed).toBeTruthy('Expected the snack bar to be dismissed');
-    expect(overlayContainerElement.childElementCount)
-        .toBe(0, 'Expected the overlay container element to have no child elements');
+    snackBarRef.afterDismissed().subscribe(null, null, () => {
+      expect(dismissed).toBeTruthy('Expected the snack bar to be dismissed');
+      expect(overlayContainerElement.childElementCount)
+          .toBe(0, 'Expected the overlay container element to have no child elements');
+    });
   });
 
   it('should open a custom component', () => {
@@ -136,7 +136,46 @@ describe('MdSnackBar', () => {
     expect(overlayContainerElement.textContent)
         .toBe('Burritos are on the way.',
               `Expected the overlay text content to be 'Burritos are on the way'`);
+  });
 
+  it('should set the animation state to visible on entry', () => {
+    let config = new MdSnackBarConfig(testViewContainerRef);
+    let snackBarRef = snackBar.open(simpleMessage, null, config);
+
+    viewContainerFixture.detectChanges();
+    expect(snackBarRef.containerInstance.animationState)
+        .toBe('visible', `Expected the animation state would be 'visible'.`);
+  });
+
+  it('should set the animation state to complete on exit', () => {
+    let config = new MdSnackBarConfig(testViewContainerRef);
+    let snackBarRef = snackBar.open(simpleMessage, null, config);
+    snackBarRef.dismiss();
+
+    viewContainerFixture.detectChanges();
+    expect(snackBarRef.containerInstance.animationState)
+        .toBe('complete', `Expected the animation state would be 'complete'.`);
+  });
+
+  it(`should set the old snack bar animation state to complete and the new snack bar animation
+      state to visible on entry of new snack bar`, () => {
+    let config = new MdSnackBarConfig(testViewContainerRef);
+    let snackBarRef = snackBar.open(simpleMessage, null, config);
+
+    viewContainerFixture.detectChanges();
+    expect(snackBarRef.containerInstance.animationState)
+        .toBe('visible', `Expected the animation state would be 'visible'.`);
+
+    let config2 = new MdSnackBarConfig(testViewContainerRef);
+    let snackBarRef2 = snackBar.open(simpleMessage, null, config2);
+
+    viewContainerFixture.detectChanges();
+    snackBarRef.afterDismissed().subscribe(null, null, () => {
+      expect(snackBarRef.containerInstance.animationState)
+          .toBe('complete', `Expected the animation state would be 'complete'.`);
+      expect(snackBarRef2.containerInstance.animationState)
+          .toBe('visible', `Expected the animation state would be 'visible'.`);
+    });
   });
 });
 

src/lib/snack-bar/snack-bar.ts

@@ -21,10 +21,6 @@ import {MdSnackBarRef} from './snack-bar-ref';
 import {MdSnackBarContainer} from './snack-bar-container';
 import {SimpleSnackBar} from './simple-snack-bar';
 
-export {MdSnackBarRef} from './snack-bar-ref';
-export {MdSnackBarConfig} from './snack-bar-config';
-
-// TODO(josephperrott): Animate entrance and exit of snack bars.
 // TODO(josephperrott): Automate dismiss after timeout.
 
 
@@ -45,14 +41,24 @@ export class MdSnackBar {
    */
   openFromComponent<T>(component: ComponentType<T>,
                        config: MdSnackBarConfig): MdSnackBarRef<T> {
-    if (this._snackBarRef) {
-      this._snackBarRef.dismiss();
-    }
     let overlayRef = this._createOverlay();
     let snackBarContainer = this._attachSnackBarContainer(overlayRef, config);
     let mdSnackBarRef = this._attachSnackbarContent(component, snackBarContainer, overlayRef);
+
+    // If a snack bar is already in view, dismiss it and enter the new snack bar after exit
+    // animation is complete.
+    if (this._snackBarRef) {
+      this._snackBarRef.afterDismissed().subscribe(() => {
+        mdSnackBarRef.containerInstance.enter();
+      });
+      this._snackBarRef.dismiss();
+    // If no snack bar is in view, enter the new snack bar.
+    } else {
+      mdSnackBarRef.containerInstance.enter();
+    }
     this._live.announce(config.announcementMessage, config.politeness);
-    return mdSnackBarRef;
+    this._snackBarRef = mdSnackBarRef;
+    return this._snackBarRef;
   }
 
   /**
@@ -88,10 +94,7 @@ export class MdSnackBar {
                                     overlayRef: OverlayRef): MdSnackBarRef<T> {
     let portal = new ComponentPortal(component);
     let contentRef = container.attachComponentPortal(portal);
-    let snackBarRef = <MdSnackBarRef<T>> new MdSnackBarRef(contentRef.instance, overlayRef);
-
-    this._snackBarRef = snackBarRef;
-    return snackBarRef;
+    return new MdSnackBarRef(contentRef.instance, container, overlayRef);
   }
 
   /**