Dynamic Clarity App Level Alerts

问题:

I am using the vmware/clarity design system and I'm trying to implement dynamic app-level alerts using the dynamic component loading outlined in angular.io. I've followed this pattern before, but I can't seem to get this to work with the alerts coming from Clarity.

app.component.ts

import { AfterViewInit, Component, ComponentFactoryResolver, OnDestroy, ViewChild } from '@angular/core';
import { ClrAlert } from '@clr/angular';

import { AlertsHostDirective } from './directives/alerts-host.directive';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent implements AfterViewInit, OnDestroy {

  @ViewChild(AlertsHostDirective) alerts: AlertsHostDirective;
  private interval: NodeJS.Timer;

  constructor(private _componentFactoryResolver: ComponentFactoryResolver) { }

  ngAfterViewInit(): void {
    this.alert();
    this.getAlerts();
  }

  ngOnDestroy(): void {
    clearInterval(this.interval);
  }

  private alert() {
    const componentFactory = this._componentFactoryResolver.resolveComponentFactory(ClrAlert);

    const viewContainerRef = this.alerts.viewContainerRef;
    const componentRef = viewContainerRef.createComponent(componentFactory);

    componentRef.instance.isAppLevel = true;
    componentRef.changeDetectorRef.detectChanges();
  }

  private getAlerts() {
    this.interval = setInterval(() => {
      this.alert();
    }, 5000);
  }

}

app.component.html

<clr-main-container>
    <clr-alerts>
        <ng-template appAlertsHost></ng-template>
        <clr-alert clrAlertType="info"
                   [clrAlertAppLevel]="true">
            <div class="alert-item">
                <span class="alert-text">This is the first app level alert.    </span>
                <div class="alert-actions">
                    <button class="btn alert-action">Fix</button>
                </div>
            </div>
        </clr-alert>
        <clr-alert clrAlertType="danger"
                   [clrAlertAppLevel]="true">
            <div class="alert-item">
                <span class="alert-text">This is a second app level alert.</span>
                <div class="alert-actions">
                    <button class="btn alert-action">Fix</button>
                </div>
            </div>
        </clr-alert>
    </clr-alerts>
...

alerts-host.directive.ts

import { Directive, ViewContainerRef } from '@angular/core';

@Directive({
  selector: '[appAlertsHost]'
})
export class AlertsHostDirective {

  constructor(public viewContainerRef: ViewContainerRef) { }

}

If I put the directive on the ClrAlerts component, it works the way it should in that app level alerts are appended after the ClrAlerts in the DOM. But I want all my app-level alerts to appear inside that component as they come in. In turn, I'd like for the pager component that appears to be updated as well.

Is this possible?

回答1:

After the discussing in the comments, I figured it would be easier if I just posted what I meant by simply using *ngFor: https://stackblitz.com/edit/clarity-light-theme-v11-vs8aig?file=app%2Fnotifications.provider.ts

Using the component factory to create always the same component is completely overkill and is a terrible practice. The section of the Angular docs you linked specifically explains that their use case is to instantiate a new component dynamically when they don't even know the actual class of the component in the first place. I hope my example above will help you understand how to organize these alerts in your project.

回答2:

@Eudes pointed out that I was making things too complicated. Basically, I just need to keep track of an array of notifications so that when something "alert-able" happens, I can just push an alert object onto the array and have them render through *ngFor.

However, there seems to an issue with the ClrAlerts parent component handling these changes correctly in certain situations. For example, if you start with alerts in the array, close them with user interaction, and then add more, the current alert is not set correctly. Therefore, this seems to be the cleanest solution I could come up with:

Template

<clr-main-container>
    <clr-alerts>
        <clr-alert *ngFor="let alert of alerts"
                   [clrAlertType]="alert.type"
                   [clrAlertAppLevel]="true">
            <div class="alert-item">
                <span class="alert-text">{{alert.text}}</span>
                <div class="alert-actions"
                     *ngIf="alert.action">
                    <button class="btn alert-action">{{alert.action}}</button>
                </div>
            </div>
        </clr-alert>
    </clr-alerts>
    ...

Component

import 'rxjs/add/Observable/of';

import { AfterViewInit, Component, OnDestroy, ViewChild } from '@angular/core';
import { ClrAlerts } from '@clr/angular';

export interface AppLevelAlert {
  type: 'info' | 'warning' | 'success' | 'danger';
  text: string;
  action: string;
}

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent implements AfterViewInit, OnDestroy {

  @ViewChild(ClrAlerts) alertsContainer: ClrAlerts;
  private interval: NodeJS.Timer;
  alerts: AppLevelAlert[] = [];

  ngAfterViewInit(): void {
    this.alert();
    this.getAlerts();
  }

  ngOnDestroy(): void {
    clearInterval(this.interval);
  }

  private alert() {
    this.alerts.push({
      type: 'success',
      text: 'This was added later!',
      action: 'Do nothing'
    });
    if (!this.alertsContainer.currentAlert) {
      this.alertsContainer.multiAlertService.current = 0;
    }
  }

  private getAlerts() {
    this.interval = setInterval(() => {
      this.alert();
    }, 5000);
  }

}