fix(tabs): re-align the ink bar when the viewport size changes

src/lib/tabs/tab-header.spec.ts

@@ -1,4 +1,4 @@
-import {async, ComponentFixture, TestBed} from '@angular/core/testing';
+import {async, ComponentFixture, TestBed, fakeAsync, tick} from '@angular/core/testing';
 import {Component, ViewChild, ViewContainerRef} from '@angular/core';
 import {LayoutDirection, Dir} from '../core/rtl/dir';
 import {MdTabHeader} from './tab-header';
@@ -11,6 +11,7 @@ import {RIGHT_ARROW, LEFT_ARROW, ENTER} from '../core/keyboard/keycodes';
 import {FakeViewportRuler} from '../core/overlay/position/fake-viewport-ruler';
 import {ViewportRuler} from '../core/overlay/position/viewport-ruler';
 import {dispatchKeyboardEvent} from '../core/testing/dispatch-events';
+import {dispatchFakeEvent} from '../core/testing/dispatch-events';
 import {Subject} from 'rxjs/Subject';
 
 
@@ -211,6 +212,21 @@ describe('MdTabHeader', () => {
       expect(inkBar.alignToElement).toHaveBeenCalled();
     });
 
+    it('should re-align the ink bar when the window is resized', fakeAsync(() => {
+      fixture = TestBed.createComponent(SimpleTabHeaderApp);
+      fixture.detectChanges();
+
+      const inkBar = fixture.componentInstance.mdTabHeader._inkBar;
+
+      spyOn(inkBar, 'alignToElement');
+
+      dispatchFakeEvent(window, 'resize');
+      tick(10);
+      fixture.detectChanges();
+
+      expect(inkBar.alignToElement).toHaveBeenCalled();
+    }));
+
   });
 });
 

src/lib/tabs/tab-header.ts

@@ -12,13 +12,20 @@ import {
   AfterContentChecked,
   AfterContentInit,
   OnDestroy,
+  NgZone,
 } from '@angular/core';
 import {RIGHT_ARROW, LEFT_ARROW, ENTER, Dir, LayoutDirection} from '../core';
 import {MdTabLabelWrapper} from './tab-label-wrapper';
 import {MdInkBar} from './ink-bar';
 import {Subscription} from 'rxjs/Subscription';
+import {Observable} from 'rxjs/Observable';
 import {applyCssTransform} from '../core/style/apply-transform';
 import 'rxjs/add/operator/map';
+import 'rxjs/add/operator/auditTime';
+import 'rxjs/add/observable/of';
+import 'rxjs/add/observable/merge';
+import 'rxjs/add/operator/startWith';
+
 
 /**
  * The directions that scrolling can go in when the header's tabs exceed the header width. 'After'
@@ -68,8 +75,8 @@ export class MdTabHeader implements AfterContentChecked, AfterContentInit, OnDes
   /** Whether the header should scroll to the selected index after the view has been checked. */
   private _selectedIndexChanged = false;
 
-  /** Subscription to changes in the layout direction. */
-  private _directionChange: Subscription;
+  /** Combines listeners that will re-align the ink bar whenever they're invoked. */
+  private _realignInkBar: Subscription = null;
 
   /** Whether the controls for pagination should be displayed */
   _showPaginationControls = false;
@@ -92,21 +99,25 @@ export class MdTabHeader implements AfterContentChecked, AfterContentInit, OnDes
   private _selectedIndex: number = 0;
 
   /** The index of the active tab. */
-  @Input() set selectedIndex(value: number) {
+  @Input()
+  get selectedIndex(): number { return this._selectedIndex; }
+  set selectedIndex(value: number) {
     this._selectedIndexChanged = this._selectedIndex != value;
 
     this._selectedIndex = value;
     this._focusIndex = value;
   }
-  get selectedIndex(): number { return this._selectedIndex; }
 
   /** Event emitted when the option is selected. */
   @Output() selectFocusedIndex = new EventEmitter();
 
   /** Event emitted when a label is focused. */
   @Output() indexFocused = new EventEmitter();
 
-  constructor(private _elementRef: ElementRef, @Optional() private _dir: Dir) {}
+  constructor(
+    private _elementRef: ElementRef,
+    private _ngZone: NgZone,
+    @Optional() private _dir: Dir) { }
 
   ngAfterContentChecked(): void {
     // If the number of tab labels have changed, check if scrolling should be enabled
@@ -150,17 +161,23 @@ export class MdTabHeader implements AfterContentChecked, AfterContentInit, OnDes
    * Aligns the ink bar to the selected tab on load.
    */
   ngAfterContentInit() {
-    this._alignInkBarToSelectedTab();
-
-    if (this._dir) {
-      this._directionChange = this._dir.dirChange.subscribe(() => this._alignInkBarToSelectedTab());
-    }
+    this._realignInkBar = this._ngZone.runOutsideAngular(() => {
+      let dirChange = this._dir ? this._dir.dirChange : Observable.of(null);
+      let resize = typeof window !== 'undefined' ?
+          Observable.fromEvent(window, 'resize').auditTime(10) :
+          Observable.of(null);
+
+      return Observable.merge(dirChange, resize).startWith(null).subscribe(() => {
+        this._updatePagination();
+        this._alignInkBarToSelectedTab();
+      });
+    });
   }
 
   ngOnDestroy() {
-    if (this._directionChange) {
-      this._directionChange.unsubscribe();
-      this._directionChange = null;
+    if (this._realignInkBar) {
+      this._realignInkBar.unsubscribe();
+      this._realignInkBar = null;
     }
   }
 

src/lib/tabs/tab-nav-bar/tab-nav-bar.spec.ts

@@ -1,13 +1,18 @@
-import {async, ComponentFixture, TestBed} from '@angular/core/testing';
+import {async, ComponentFixture, TestBed, fakeAsync, tick} from '@angular/core/testing';
 import {MdTabsModule} from '../index';
-import {Component} from '@angular/core';
+import {MdTabNavBar} from './tab-nav-bar';
+import {Component, ViewChild} from '@angular/core';
 import {By} from '@angular/platform-browser';
 import {ViewportRuler} from '../../core/overlay/position/viewport-ruler';
 import {FakeViewportRuler} from '../../core/overlay/position/fake-viewport-ruler';
-import {dispatchMouseEvent} from '../../core/testing/dispatch-events';
+import {dispatchMouseEvent, dispatchFakeEvent} from '../../core/testing/dispatch-events';
+import {LayoutDirection, Dir} from '../../core/rtl/dir';
+import {Subject} from 'rxjs/Subject';
 
 
 describe('MdTabNavBar', () => {
+  let dir: LayoutDirection = 'ltr';
+  let dirChange = new Subject();
 
   beforeEach(async(() => {
     TestBed.configureTestingModule({
@@ -17,6 +22,9 @@ describe('MdTabNavBar', () => {
         TabLinkWithNgIf,
       ],
       providers: [
+        {provide: Dir, useFactory: () => {
+          return {value: dir,  dirChange: dirChange.asObservable()};
+        }},
         {provide: ViewportRuler, useClass: FakeViewportRuler},
       ]
     });
@@ -44,6 +52,29 @@ describe('MdTabNavBar', () => {
       tabLink.nativeElement.click();
       expect(component.activeIndex).toBe(2);
     });
+
+    it('should re-align the ink bar when the direction changes', () => {
+      const inkBar = fixture.componentInstance.tabNavBar._inkBar;
+
+      spyOn(inkBar, 'alignToElement');
+
+      dirChange.next();
+      fixture.detectChanges();
+
+      expect(inkBar.alignToElement).toHaveBeenCalled();
+    });
+
+    it('should re-align the ink bar when the window is resized', fakeAsync(() => {
+      const inkBar = fixture.componentInstance.tabNavBar._inkBar;
+
+      spyOn(inkBar, 'alignToElement');
+
+      dispatchFakeEvent(window, 'resize');
+      tick(10);
+      fixture.detectChanges();
+
+      expect(inkBar.alignToElement).toHaveBeenCalled();
+    }));
   });
 
   it('should clean up the ripple event handlers on destroy', () => {
@@ -73,6 +104,8 @@ describe('MdTabNavBar', () => {
   `
 })
 class SimpleTabNavBarTestApp {
+  @ViewChild(MdTabNavBar) tabNavBar: MdTabNavBar;
+
   activeIndex = 0;
 }
 

src/lib/tabs/tab-nav-bar/tab-nav-bar.ts

@@ -9,12 +9,17 @@ import {
   Inject,
   Optional,
   OnDestroy,
+  AfterContentInit,
 } from '@angular/core';
 import {MdInkBar} from '../ink-bar';
 import {MdRipple} from '../../core/ripple/index';
 import {ViewportRuler} from '../../core/overlay/position/viewport-ruler';
 import {MD_RIPPLE_GLOBAL_OPTIONS, RippleGlobalOptions, Dir} from '../../core';
+import {Observable} from 'rxjs/Observable';
 import {Subscription} from 'rxjs/Subscription';
+import 'rxjs/add/operator/auditTime';
+import 'rxjs/add/observable/of';
+import 'rxjs/add/observable/merge';
 
 /**
  * Navigation component matching the styles of the tab group header.
@@ -30,25 +35,34 @@ import {Subscription} from 'rxjs/Subscription';
   },
   encapsulation: ViewEncapsulation.None,
 })
-export class MdTabNavBar implements OnDestroy {
-  private _directionChange: Subscription;
+export class MdTabNavBar implements AfterContentInit, OnDestroy {
+  /** Combines listeners that will re-align the ink bar whenever they're invoked. */
+  private _realignInkBar: Subscription = null;
+
   _activeLinkChanged: boolean;
   _activeLinkElement: ElementRef;
 
   @ViewChild(MdInkBar) _inkBar: MdInkBar;
 
-  constructor(@Optional() private _dir: Dir) {
-    if (_dir) {
-      this._directionChange = _dir.dirChange.subscribe(() => this._alignInkBar());
-    }
-  }
+  constructor(@Optional() private _dir: Dir, private _ngZone: NgZone) { }
 
   /** Notifies the component that the active link has been changed. */
   updateActiveLink(element: ElementRef) {
     this._activeLinkChanged = this._activeLinkElement != element;
     this._activeLinkElement = element;
   }
 
+  ngAfterContentInit(): void {
+    this._realignInkBar = this._ngZone.runOutsideAngular(() => {
+      let dirChange = this._dir ? this._dir.dirChange : Observable.of(null);
+      let resize = typeof window !== 'undefined' ?
+          Observable.fromEvent(window, 'resize').auditTime(10) :
+          Observable.of(null);
+
+      return Observable.merge(dirChange, resize).subscribe(() => this._alignInkBar());
+    });
+  }
+
   /** Checks if the active link has been changed and, if so, will update the ink bar. */
   ngAfterContentChecked(): void {
     if (this._activeLinkChanged) {
@@ -58,15 +72,17 @@ export class MdTabNavBar implements OnDestroy {
   }
 
   ngOnDestroy() {
-    if (this._directionChange) {
-      this._directionChange.unsubscribe();
-      this._directionChange = null;
+    if (this._realignInkBar) {
+      this._realignInkBar.unsubscribe();
+      this._realignInkBar = null;
     }
   }
 
   /** Aligns the ink bar to the active link. */
   private _alignInkBar(): void {
-    this._inkBar.alignToElement(this._activeLinkElement.nativeElement);
+    if (this._activeLinkElement) {
+      this._inkBar.alignToElement(this._activeLinkElement.nativeElement);
+    }
   }
 }