如何使用OnChanges angular来改变背景颜色？

import { Component, Input, OnChanges, SimpleChanges } from '@angular/core';

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css']
})
export class MyComponentComponent implements OnChanges {
  @Input() backgroundColor: string;

  constructor() { }

  ngOnChanges(changes: SimpleChanges): void {
    if (changes.backgroundColor) {
      const color = changes.backgroundColor.currentValue;
      this.changeBackgroundColor(color);
    }
  }

  changeBackgroundColor(color: string): void {
    // 在这里进行背景颜色的改变操作
    document.body.style.backgroundColor = color;
  }
}

<app-my-component [backgroundColor]="myColor"></app-my-component>

export class ParentComponent {
  myColor: string;

  constructor() {
    this.myColor = 'red'; // 初始化背景颜色
  }

  changeColor(): void {
    this.myColor = 'blue'; // 改变背景颜色
  }
}

<button (click)="changeColor()">改变背景颜色</button>