这可能是有关Angular动画的问题，可以尝试使用以下代码片段：

import { Component, ViewChild, Renderer2, AnimationPlayer, ElementRef } from '@angular/core';
import { trigger, state, style, animate, transition, AnimationEvent } from '@angular/animations';

@Component({
  selector: 'app-example',
  template: `
    
动画示例
  `,
  animations: [
    trigger('myTrigger', [
      state('start', style({ opacity: 1 })),
      state('end', style({ opacity: 0 })),
      transition('start => end', [
        animate(2000, style({ opacity: 0 }))
      ]),
      transition('end => start', [
        animate(2000, style({ opacity: 1 }))
      ])
    ])
  ]
})
export class ExampleComponent {
  @ViewChild('myContent') myContent: ElementRef;
  player: AnimationPlayer;

  constructor(private renderer: Renderer2) { }

  ngAfterViewInit() {
    this.renderer.listen(this.myContent.nativeElement, 'animationstart', (event: AnimationEvent) => {
      console.log('Animation Start Event: ', event);
      // Do something when the animation starts
    });

    this.renderer.listen(this.myContent.nativeElement, 'animationend', (event: AnimationEvent) => {
      console.log('Animation End Event: ', event);
      // Do something when the animation ends
    });

    this.player = this.renderer
      .createRenderer(this.myContent.nativeElement, true)
      .animate(this.myContent.nativeElement, {
        animation: 'myTrigger',
        keyframes: [
          { offset: 0, transform: 'scale(1)' },
          { offset: 0.5, transform: 'scale(1.2)' },
          { offset: 1, transform: 'scale(1)' }
        ],
        duration: 1500,
        delay: 0,
        easing: 'ease-in-out',
        fill: 'both'
      });

    this.player.play();
  }
}

通过在视图初始化之后使用Renderer2监听来自动画元素的“animationstart”和“animationend”事件，您可以确保您的动画逻辑能够正确地处理这些事件。 此外，代码片段中的添加一个动画player并通过调用play()方法启动它，以确保CSS动画触发。