如何将sidenav（mat-drawer）状态保存到Angular Material中的localstorage？

Question

我对 Angular Material 中的垫子抽屉有疑问。我想将我的状态保存到 localstorage，但 mat-drawer 总是打开的。

Sidenav 在没有文字的垫子图标时有展开部分和关闭展开部分。当您点击底部按钮 Hide 时，sidenav 为 Close，但在刷新页面后 Sidenav 再次展开（但在 localstorage 中已关闭）。

看起来像这样：

Opened expanded mat drawer

Closed mat drawer

Sidenav is open but in local storage is closed

你知道如何解决这个问题吗？谢谢！

源代码：

app.component.html

<mat-drawer-container class="content-container" autosize >
 <mat-drawer
  mode="side"
  class="sidenav"
  disableClose="true"
  opened="true">
<div class="sidenav-container">
<mat-nav-list>
      <a class="nav-item nav-link" mat-list-item routerLink="/private/dashboard" routerLinkActive="active" [routerLinkActiveOptions]="{ exact: true }">
        <mat-icon style="padding-right:5px;"  matTooltipPosition="right" [matTooltipDisabled]="disabledTooltip">dashboard</mat-icon>
        <span *ngIf="isExpanded">Dashboard</span>
      </a>

      <a class="nav-item nav-link" mat-list-item routerLink="/private/companies" routerLinkActive="active">
        <mat-icon style="padding-right:5px;">stars</mat-icon>
        <span *ngIf="isExpanded">Subjects</span>
      </a>

      <a class="nav-item nav-link" mat-list-item routerLink="/private/users" routerLinkActive="active">
        <mat-icon style="padding-right:5px;">group</mat-icon>
        <span *ngIf="isExpanded">Users</span>
      </a>

      <a class="nav-item nav-link" mat-list-item routerLink="/private/api-customers" routerLinkActive="active">
        <mat-icon style="padding-right:5px;">beenhere</mat-icon>
        <span *ngIf="isExpanded">Clients</span>
      </a>

      <a class="nav-item nav-link" mat-list-item routerLink="/private/applications" routerLinkActive="active">
        <mat-icon style="padding-right:5px;">apps</mat-icon>
        <span *ngIf="isExpanded">Apps</span>
      </a>

      <a class="nav-item nav-link" mat-list-item routerLink="/private/calendar" routerLinkActive="active">
        <mat-icon style="padding-right:5px;">calendar_today</mat-icon>
        <span *ngIf="isExpanded">Calendar</span>
      </a>
</mat-nav-list>
        <div class="sidenav-bottom">
          <mat-nav-list>
            <a class="nav-item nav-link" mat-list-item (click)="onSidenavToggle()">
              <mat-icon *ngIf="isExpanded">arrow_back_ios</mat-icon>
              <mat-icon *ngIf="!isExpanded">arrow_forward_ios</mat-icon>
              <span *ngIf="isExpanded">Hide</span>
            </a>
          </mat-nav-list>
        </div>
    </mat-drawer>
<mat-drawer-content>
Page content
</mat-drawer-content>
</mat-drawer-container>

app.component.ts

import {Component, HostListener, Inject, OnInit} from '@angular/core';
import { Router } from '@angular/router';
import {Subject} from 'rxjs';

@Component({
  selector: 'app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
})

export class AppComponent  {

  isExpanded = true;
  constructor(
  private sidenavService: SidebarService) {
  this.sidenavService.setHideSidebar(this.sidenavService.isHideSidebar());
  }
  onSidenavToggle() {
    this.isExpanded = !this.isExpanded;
    this.sidenavService.setHideSidebar(!this.sidenavService.isHideSidebar());
    this.sidenavService.sideBarState$.next(this.isExpanded);
  }}

sidebar.service.ts

import { Injectable } from '@angular/core';
import { Subject } from 'rxjs';


@Injectable()
export class SidebarService {

  public sideBarState$: Subject<boolean> = new Subject<boolean>();

  constructor() {
    const initialValue = localStorage.getItem('isExpanded');
    this.sideBarState$.next(initialValue === 'close');
  }

  getHideSidebar(): Subject<boolean> {
    return this.sideBarState$;
  }

  setHideSidebar(newValue: boolean): void {
    localStorage.setItem('isExpanded', newValue ? 'close' : 'open');
    this.sideBarState$.next(newValue);
  }

  isHideSidebar(): boolean {
    return localStorage.getItem('isExpanded') === 'close';
  }

}

Answer 1

原来问题出在组件中的isExpanded。该值被硬编码为true，与服务（或存储在LOCALSTORAGE中的值）无关。

其他一些建议是单独使用 Subject 值作为 isExpanded 应该是的一个真正来源（使用 EMIT 值，不要自己设置）。如果您将isExpanded 存储为true 或false，而不是open 或close，也会更有意义。变量名表明该值为真或假。

import {Component, HostListener, Inject, OnInit} from '@angular/core';
import { Router } from '@angular/router';
import {Subject} from 'rxjs';

@Component({
  selector: 'app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
})

export class AppComponent  {

  isExpanded;
  constructor(
  private sidenavService: SidebarService) {
  isExpanded = !this.sidenavService.isHideSidebar();
  }
  onSidenavToggle() {
    this.isExpanded = !this.isExpanded;
    this.sidenavService.setHideSidebar(!this.sidenavService.isHideSidebar());
    this.sidenavService.sideBarState$.next(this.isExpanded);
  }}