Angular - 等待Google身份验证完成

Question

我正在尝试在Angular 4中正常使用Google身份验证。问题是代码在继续执行之前不会等待Google身份验证弹出窗口的结果。

实际登录有效，它只是控制导致我麻烦的下一步。我已经尝试添加一个“getLoginResult”方法，该方法返回一个observable，但它没有帮助。

login() {
  this._authService.getLoginResult()
    .subscribe(results => {

     if(results === true) {
       // want to do something here
     }
     else {
       // this always gets executed b/c auth window hasn't returned
     }
  }
}

在authService中......

getLoginResult(): Observable<boolean> {        
    if(this.signIn()) {
      return Observable.of(true);
    }
    else {
      return Observable.of(false);
    }
}

signIn() {
    const signOptions: gapi.auth2.SigninOptions = {scope: SCOPES };
    if (this._googleAuth) {
      Observable.fromPromise(this._googleAuth.signIn(signOptions))
        .subscribe((response: any) => this.handleSuccessLogin(response), error => this.handleFailedLogin(error));
    }
}

我也尝试从signIn返回结果。

signIn(): boolean {
    const signOptions: gapi.auth2.SigninOptions = {scope: SCOPES };
    if (this._googleAuth) {
      Observable.fromPromise(this._googleAuth.signIn(signOptions))
        .subscribe(response => {
        if(response === true) {
          return true;
        }
        else {
          return false;
        }
      });
    }
    else {
      return false;
    }
  }