如何在Angular中侦听组件中的服务变量更改

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

@Injectable()
export class MyService {
  private myVariable = new Subject<string>();

  myVariable$ = this.myVariable.asObservable();

  updateVariable(newValue: string) {
    this.myVariable.next(newValue);
  }
}

import { Component, OnInit, OnDestroy } from '@angular/core';
import { MyService } from 'path/to/my-service';
import { Subscription } from 'rxjs';

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css']
})
export class MyComponent implements OnInit, OnDestroy {
  myVariable: string;
  private subscription: Subscription;

  constructor(private myService: MyService) { }

  ngOnInit() {
    this.subscription = this.myService.myVariable$.subscribe(newValue => {
      this.myVariable = newValue;
      // 执行其他操作
    });
  }

  ngOnDestroy() {
    this.subscription.unsubscribe();
  }
}