fix(datepicker): re-render calendar when locale changes

src/material/datepicker/calendar.spec.ts

@@ -283,6 +283,45 @@ describe('MatCalendar', () => {
       });
     });
 
+    it('should re-render the month view when the locale changes',
+      inject([DateAdapter], (adapter: DateAdapter<Date>) => {
+        fixture.detectChanges();
+        spyOn(calendarInstance.monthView, '_init').and.callThrough();
+
+        adapter.setLocale('bg-BG');
+        fixture.detectChanges();
+
+        expect(calendarInstance.monthView._init).toHaveBeenCalled();
+      }));
+
+    it('should re-render the year view when the locale changes',
+      inject([DateAdapter], (adapter: DateAdapter<Date>) => {
+        periodButton.click();
+        fixture.detectChanges();
+
+        (calendarElement.querySelector('.mat-calendar-body-active') as HTMLElement).click();
+        fixture.detectChanges();
+
+        spyOn(calendarInstance.yearView, '_init').and.callThrough();
+
+        adapter.setLocale('bg-BG');
+        fixture.detectChanges();
+
+        expect(calendarInstance.yearView._init).toHaveBeenCalled();
+      }));
+
+    it('should re-render the multi-year view when the locale changes',
+      inject([DateAdapter], (adapter: DateAdapter<Date>) => {
+        periodButton.click();
+        fixture.detectChanges();
+
+        spyOn(calendarInstance.multiYearView, '_init').and.callThrough();
+
+        adapter.setLocale('bg-BG');
+        fixture.detectChanges();
+
+        expect(calendarInstance.multiYearView._init).toHaveBeenCalled();
+      }));
   });
 
   describe('calendar with min and max date', () => {

src/material/datepicker/month-view.ts

@@ -30,11 +30,14 @@ import {
   Output,
   ViewEncapsulation,
   ViewChild,
+  OnDestroy,
 } from '@angular/core';
 import {DateAdapter, MAT_DATE_FORMATS, MatDateFormats} from '@angular/material/core';
 import {Directionality} from '@angular/cdk/bidi';
 import {MatCalendarBody, MatCalendarCell, MatCalendarCellCssClasses} from './calendar-body';
 import {createMissingDateImplError} from './datepicker-errors';
+import {Subscription} from 'rxjs';
+import {startWith} from 'rxjs/operators';
 
 
 const DAYS_PER_WEEK = 7;
@@ -51,7 +54,9 @@ const DAYS_PER_WEEK = 7;
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush
 })
-export class MatMonthView<D> implements AfterContentInit {
+export class MatMonthView<D> implements AfterContentInit, OnDestroy {
+  private _rerenderSubscription = Subscription.EMPTY;
+
   /**
    * The date to display in this month view (everything other than the month and year is ignored).
    */
@@ -147,7 +152,13 @@ export class MatMonthView<D> implements AfterContentInit {
   }
 
   ngAfterContentInit() {
-    this._init();
+    this._rerenderSubscription = this._dateAdapter.localeChanges
+      .pipe(startWith(null))
+      .subscribe(() => this._init());
+  }
+
+  ngOnDestroy() {
+    this._rerenderSubscription.unsubscribe();
   }
 
   /** Handles when a new date is selected. */

src/material/datepicker/multi-year-view.ts

@@ -29,11 +29,14 @@ import {
   Output,
   ViewChild,
   ViewEncapsulation,
+  OnDestroy,
 } from '@angular/core';
 import {DateAdapter} from '@angular/material/core';
 import {Directionality} from '@angular/cdk/bidi';
 import {MatCalendarBody, MatCalendarCell} from './calendar-body';
 import {createMissingDateImplError} from './datepicker-errors';
+import {Subscription} from 'rxjs';
+import {startWith} from 'rxjs/operators';
 
 export const yearsPerPage = 24;
 
@@ -50,7 +53,9 @@ export const yearsPerRow = 4;
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush
 })
-export class MatMultiYearView<D> implements AfterContentInit {
+export class MatMultiYearView<D> implements AfterContentInit, OnDestroy {
+  private _rerenderSubscription = Subscription.EMPTY;
+
   /** The date to display in this multi-year view (everything other than the year is ignored). */
   @Input()
   get activeDate(): D { return this._activeDate; }
@@ -127,7 +132,13 @@ export class MatMultiYearView<D> implements AfterContentInit {
   }
 
   ngAfterContentInit() {
-    this._init();
+    this._rerenderSubscription = this._dateAdapter.localeChanges
+      .pipe(startWith(null))
+      .subscribe(() => this._init());
+  }
+
+  ngOnDestroy() {
+    this._rerenderSubscription.unsubscribe();
   }
 
   /** Initializes this multi-year view. */

src/material/datepicker/year-view.ts

@@ -30,11 +30,14 @@ import {
   Output,
   ViewChild,
   ViewEncapsulation,
+  OnDestroy,
 } from '@angular/core';
 import {DateAdapter, MAT_DATE_FORMATS, MatDateFormats} from '@angular/material/core';
 import {Directionality} from '@angular/cdk/bidi';
 import {MatCalendarBody, MatCalendarCell} from './calendar-body';
 import {createMissingDateImplError} from './datepicker-errors';
+import {Subscription} from 'rxjs';
+import {startWith} from 'rxjs/operators';
 
 /**
  * An internal component used to display a single year in the datepicker.
@@ -47,7 +50,9 @@ import {createMissingDateImplError} from './datepicker-errors';
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush
 })
-export class MatYearView<D> implements AfterContentInit {
+export class MatYearView<D> implements AfterContentInit, OnDestroy {
+  private _rerenderSubscription = Subscription.EMPTY;
+
   /** The date to display in this year view (everything other than the year is ignored). */
   @Input()
   get activeDate(): D { return this._activeDate; }
@@ -132,7 +137,13 @@ export class MatYearView<D> implements AfterContentInit {
   }
 
   ngAfterContentInit() {
-    this._init();
+    this._rerenderSubscription = this._dateAdapter.localeChanges
+      .pipe(startWith(null))
+      .subscribe(() => this._init());
+  }
+
+  ngOnDestroy() {
+    this._rerenderSubscription.unsubscribe();
   }
 
   /** Handles when a new month is selected. */

tools/public_api_guard/material/datepicker.d.ts

@@ -244,7 +244,7 @@ export declare class MatDatepickerToggleIcon {
     static ɵfac: i0.ɵɵFactoryDef<MatDatepickerToggleIcon>;
 }
 
-export declare class MatMonthView<D> implements AfterContentInit {
+export declare class MatMonthView<D> implements AfterContentInit, OnDestroy {
     _dateAdapter: DateAdapter<D>;
     _firstWeekOffset: number;
     _matCalendarBody: MatCalendarBody;
@@ -271,11 +271,12 @@ export declare class MatMonthView<D> implements AfterContentInit {
     _handleCalendarBodyKeydown(event: KeyboardEvent): void;
     _init(): void;
     ngAfterContentInit(): void;
+    ngOnDestroy(): void;
     static ɵcmp: i0.ɵɵComponentDefWithMeta<MatMonthView<any>, "mat-month-view", ["matMonthView"], { 'activeDate': "activeDate", 'selected': "selected", 'minDate': "minDate", 'maxDate': "maxDate", 'dateFilter': "dateFilter", 'dateClass': "dateClass" }, { 'selectedChange': "selectedChange", '_userSelection': "_userSelection", 'activeDateChange': "activeDateChange" }, never>;
     static ɵfac: i0.ɵɵFactoryDef<MatMonthView<any>>;
 }
 
-export declare class MatMultiYearView<D> implements AfterContentInit {
+export declare class MatMultiYearView<D> implements AfterContentInit, OnDestroy {
     _dateAdapter: DateAdapter<D>;
     _matCalendarBody: MatCalendarBody;
     _selectedYear: number | null;
@@ -296,11 +297,12 @@ export declare class MatMultiYearView<D> implements AfterContentInit {
     _init(): void;
     _yearSelected(year: number): void;
     ngAfterContentInit(): void;
+    ngOnDestroy(): void;
     static ɵcmp: i0.ɵɵComponentDefWithMeta<MatMultiYearView<any>, "mat-multi-year-view", ["matMultiYearView"], { 'activeDate': "activeDate", 'selected': "selected", 'minDate': "minDate", 'maxDate': "maxDate", 'dateFilter': "dateFilter" }, { 'selectedChange': "selectedChange", 'yearSelected': "yearSelected", 'activeDateChange': "activeDateChange" }, never>;
     static ɵfac: i0.ɵɵFactoryDef<MatMultiYearView<any>>;
 }
 
-export declare class MatYearView<D> implements AfterContentInit {
+export declare class MatYearView<D> implements AfterContentInit, OnDestroy {
     _dateAdapter: DateAdapter<D>;
     _matCalendarBody: MatCalendarBody;
     _months: MatCalendarCell[][];
@@ -321,6 +323,7 @@ export declare class MatYearView<D> implements AfterContentInit {
     _init(): void;
     _monthSelected(month: number): void;
     ngAfterContentInit(): void;
+    ngOnDestroy(): void;
     static ɵcmp: i0.ɵɵComponentDefWithMeta<MatYearView<any>, "mat-year-view", ["matYearView"], { 'activeDate': "activeDate", 'selected': "selected", 'minDate': "minDate", 'maxDate': "maxDate", 'dateFilter': "dateFilter" }, { 'selectedChange': "selectedChange", 'monthSelected': "monthSelected", 'activeDateChange': "activeDateChange" }, never>;
     static ɵfac: i0.ɵɵFactoryDef<MatYearView<any>>;
 }