niaomingjian niaomingjian - 4 days ago 5
jQuery Question

How to navigate/focus to the next item in Angular2?

I want to focus to the next item using Arrow keys.

In keydown event handler, I use event.currentTarget.nextSibling to access the next item.

Is there another way to accomplish this?

In the event handler, I want to use JQuery to do this. How to do this?

<ul>
<li *ngFor = "let work of works" tabindex="-1" (keydown.ArrowDown)="handleKeyEvent( $event, 'Arrow Down' )">
<div class="guide-label">
<div>{{work.cd}}</div>
<div>{{work.name}}</div>
</div>
</li>
</ul>

export class WorkComponent {
...
handleKeyEvent(event: Event): void {

event.currentTarget.nextSibling.focus();
event.preventDefault();
}
}

Answer

Create a focus directive (and register it in your NgModule) that calls focus() on the host element when the input value changes to true:

@Directive({
  selector : '[myFocus]'
})
class MyFocus {
  constructor(public renderer: Renderer, public elementRef: ElementRef) {}

  @Input()
  set myFocus(value :boolean) {
    if(value) {
      this.renderer.invokeElementMethod(
          this.elementRef.nativeElement, 'focus', []);
    }
  }
}

Add the selector and a binding that passes true or false to the directive when it is supposed to be focused:

<li *ngFor = "let work of works let idx=index" tabindex="-1" 
    [myFocus]="idx == focusedIdx" (keydown.ArrowDown)="handleKeyEvent( $event, 'Arrow Down' )">

Update focusedIdx on key events:

       handleKeyEvent(event: Event): void {
            this.focusedIdx++;
        }

See also Angular 2: Focus on newly added input element

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