以下是一个在Angular 9中实现当鼠标悬停在注入的HTML上时打开浮动组件的解决方案的代码示例：

1.创建一个名为hover.directive.ts的指令文件：

import { Directive, ElementRef, HostListener, Input, ComponentFactoryResolver, ViewContainerRef } from '@angular/core';
import { HoverComponent } from './hover.component';

@Directive({
  selector: '[appHover]'
})
export class HoverDirective {
  @Input() hoverText: string;

  constructor(
    private elementRef: ElementRef,
    private resolver: ComponentFactoryResolver,
    private viewContainerRef: ViewContainerRef
  ) {}

  @HostListener('mouseenter') onMouseEnter() {
    const componentFactory = this.resolver.resolveComponentFactory(HoverComponent);
    const componentRef = this.viewContainerRef.createComponent(componentFactory);
    componentRef.instance.text = this.hoverText;
    componentRef.instance.position = this.elementRef.nativeElement.getBoundingClientRect();
  }

  @HostListener('mouseleave') onMouseLeave() {
    this.viewContainerRef.clear();
  }
}

2.创建一个名为hover.component.ts的浮动组件文件：

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

@Component({
  selector: 'app-hover',
  template: `
    

      
{{ text }}
    
  `,
  styles: [
    `
    .hover-container {
      position: absolute;
      background-color: #f1f1f1;
      padding: 10px;
      border: 1px solid #ccc;
    }
    `
  ]
})
export class HoverComponent implements OnInit {
  @Input() text: string;
  @Input() position: DOMRect;

  constructor() { }

  ngOnInit() {
  }

}

3.在需要使用指令的组件中，例如app.component.html：

Hover over me

确保在app.module.ts中声明和导入HoverDirective和HoverComponent。

这样，当鼠标悬停在