如何在Angular中切换黑暗模式

Question

当用户切换位于标题组件中的开关时，我试图切换暗模式。参见下图：

<nav class="navbar navbar-expand-lg navbar-light bg-light">
    <a class="navbar-brand" href="#">Navbar</a>
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavAltMarkup" aria-controls="navbarNavAltMarkup" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarNavAltMarkup">
      <div class="navbar-nav">
        <a class="nav-item nav-link active" href="/">Home <span class="sr-only">(current)</span></a>
        <a class="nav-item nav-link" href="/about">About</a>
        <a class="nav-item nav-link" href="/contact">Contact</a>
        <a class="nav-item nav-link" href="/resume">Resume</a>
      </div>
    </div>
    <div class="custom-control custom-switch">
        <input (change)="onChangeToggle()" type="checkbox" class="custom-control-input" id="toggleTheme">
        <label class="custom-control-label" for="toggleTheme">Dark Mode</label>
      </div>
  </nav>

我的标头组件ts文件包含一个名为setDark的布尔值，该布尔值在事件发射器中通过Output装饰器触发：

// header.component.ts

import { Component, OnInit , Output, EventEmitter} from '@angular/core';

@Component({
  selector: 'app-header',
  templateUrl: './header.component.html',
  styleUrls: ['./header.component.css']
})
export class HeaderComponent implements OnInit {

  @Output() mode = new EventEmitter<boolean>();

  setDark = false;

  constructor() { }

  ngOnInit(): void {

  }

  onChangeToggle() {
    this.setDark = !this.setDark;
    this.mode.emit(this.setDark);
    console.log(this.setDark);
  }

}

然后在app.comoonent.html中接收布尔值

 <app-header (mode)="receiveMode($event)"></app-header>

  <router-outlet></router-outlet>



// app.component.ts


import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {

  setMode = false;

  receiveMode($event) {
    this.setMode = $event;
    console.log("MODEEEE", this.setMode);
  }



  title = 'about-me';
} 

我试图像这样将div包裹在app-header和router-out周围：

<app-header (mode)="receiveMode($event)"></app-header>
<div class="darkTheme">
  <router-outlet></router-outlet>

并使用ngClass：

<div [ngClass]="{
  darkTheme: setMode
}">
</div>

但是它不起作用。我确实检查了切换开关时布尔值是否已登录到控制台。是的。

Answer 1

看看这个堆叠闪电战：https://stackblitz.com/edit/angular-rubaka?file=src/app/toolbar-multirow-example.html

它在#container：ElementRef：

上切换类“黑暗主题”

<div #container style="padding: 4rem;" class="mat-typography dark-theme">

styles.scss在第28行（默认主题）定义了两个不同的主题...

// Include the default theme styles.
@include angular-material-theme($candy-app-theme);

并在第39行（深色主题）...

.dark-theme {
  @include angular-material-theme($dark-theme)
};

希望这会有所帮助。