问Ionic 5，短信检索器，StartWatching()不工作

EN

export class HomePage implements OnInit {

    hash: any;
    Sms: any;
    constructor(private smsRetriever: SmsRetriever) { }

    ngOnInit(): void {

        this.smsRetriever.getAppHash()
            .then((res: any) => alert(res))
            .catch((error: any) => alert(error));

        this.smsRetriever.startWatching()
            .then((res: any) => alert(res))
            .catch((error: any) => alert(error));
    }
}