将URL值从父级传递给子级

我正在尝试将URL值从父级传递给子级。我在利用 @input .

浏览器控制台上打印的错误信息:

Assertion failed: We should have an asset uri when initializing the parsing.

我该怎么解决这个问题?

父母亲组成部分ts

this.myService.getSchoolURL().subscribe(
    
    (response) =>
    {
              this.uri = response 
    },
    (error) => 
    {
      alert(JSON.stringify(error));
    }
  );

父母亲组成部分html

<my-child [childSchoolUrl]="uri"></my-child>

小孩组成部分ts

''''
constructor(private platform: Platform) {}
@Input() public childSchoolUrl: string | undefined;


ngAfterViewInit(): void {
   console.log("Print what came from parent "+ this.childSchoolUrl);

   // I will be using this URL to initialize a player. I have not shown the code here assuming 
   // it is out of scope for this question.
}