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问题:

How can I detect clicks outside a component in Angular?

回答1:

import { Component, ElementRef, HostListener, Input } from '@angular/core';

@Component({
  selector: 'selector',
  template: `
    <div>
      {{text}}
    </div>
  `
})
export class AnotherComponent {
  public text: String;

  @HostListener('document:click', ['$event'])
  clickout(event) {
    if(this.eRef.nativeElement.contains(event.target)) {
      this.text = "clicked inside";
    } else {
      this.text = "clicked outside";
    }
  }

  constructor(private eRef: ElementRef) {
    this.text = 'no clicks yet';
  }
}

A working example - click here

回答2:

An alternative to AMagyar's answer. This version works when you click on element that gets removed from the DOM with an ngIf.

http://plnkr.co/edit/4mrn4GjM95uvSbQtxrAS?p=preview

  private wasInside = false;
  
  @HostListener('click')
  clickInside() {
    this.text = "clicked inside";
    this.wasInside = true;
  }
  
  @HostListener('document:click')
  clickout() {
    if (!this.wasInside) {
      this.text = "clicked outside";
    }
    this.wasInside = false;
  }

回答3:

Above mentioned answers are correct but what if you are doing a heavy process after losing the focus from the relevant component. For that, I came with a solution with two flags where the focus out event process will only take place when losing the focus from relevant component only.

isFocusInsideComponent = false;
isComponentClicked = false;

@HostListener('click')
clickInside() {
    this.isFocusInsideComponent = true;
    this.isComponentClicked = true;
}

@HostListener('document:click')
clickout() {
    if (!this.isFocusInsideComponent && this.isComponentClicked) {
        // do the heavy process

        this.isComponentClicked = false;
    }
    this.isFocusInsideComponent = false;
}

Hope this will help you. Correct me If have missed anything.

回答4:

Binding to document click through @Hostlistener is costly. It can and will have a visible performance impact if you overuse(for example, when building a custom dropdown component and you have multiple instances created in a form).

I suggest adding a @Hostlistener() to the document click event only once inside your main app component. The event should push the value of the clicked target element inside a public subject stored in a global utility service.

@Component({
  selector: 'app-root',
  template: '<router-outlet></router-outlet>'
})
export class AppComponent {

  constructor(private utilitiesService: UtilitiesService) {}

  @HostListener('document:click', ['$event'])
  documentClick(event: any): void {
    this.utilitiesService.documentClickedTarget.next(event.target)
  }
}

@Injectable({ providedIn: 'root' })
export class UtilitiesService {
   documentClickedTarget: Subject<HTMLElement> = new Subject<HTMLElement>()
}

Whoever is interested for the clicked target element should subscribe to the public subject of our utilities service and unsubscribe when the component is destroyed.

export class AnotherComponent implements OnInit {

  @ViewChild('somePopup', { read: ElementRef, static: false }) somePopup: ElementRef

  constructor(private utilitiesService: UtilitiesService) { }

  ngOnInit() {
      this.utilitiesService.documentClickedTarget
           .subscribe(target => this.documentClickListener(target))
  }

  documentClickListener(target: any): void {
     if (this.somePopup.nativeElement.contains(target))
        // Clicked inside  
     else
        // Clicked outside
  }