Add listener to custom element in DART lang

Question

In JavaScript, we can add listener to the custom element as mentioned here by:

proto.createdCallback = function() {
   this.addEventListener('click', function(e) {
   alert('Thanks!');
  });
};

I tried making equivalent DART code as:

    Element launchElement(){
       this.onClick.listen((e)=>print('Thanks!'));
       return (shadow);  
    }

Am I doing something wrong here?

the full code of my custom element is:

class MegaButton extends ButtonElement  {
  static final tag = 'mega-button';
  factory MegaButton()=>new Element.tag('button', tag);

MegaButton.created() : super.created() {
  var shadow = this.createShadowRoot();
  shadow.text='save'; 

  Element launchElement(){
    this.onClick.listen((e)=>print('Thanks!'));
    return (shadow);  
  }

}

registered it as:

document.registerElement(MegaButton.tag, MegaButton, extendsTag: 'button');

and called it by:

myDiv.nodes.add(new Element.tag('button', 'mega-button'));

What is launchElement for? You define an inner method but never call it. — Günter Zöchbauer
– Günter Zöchbauer, Commented Oct 12, 2014 at 12:49

Günter Zöchbauer · Accepted Answer · 2014-10-12 12:54:10Z

1

class MegaButton extends ButtonElement {
  static final tag = 'mega-button';

  factory MegaButton()=> new Element.tag('button', tag);

  MegaButton.created() : super.created() {
    var shadow = this.createShadowRoot();
    shadow.text = 'save';
  }

  void attached() {
    this.onClick.listen((e)=>print('Thanks!'));
  }
}

answered Oct 12, 2014 at 12:54

Günter Zöchbauer

661k235 gold badges2.1k silver badges1.6k bronze badges

Sign up to request clarification or add additional context in comments.

Comments

GioLaq · Accepted Answer · 2014-10-12 12:27:47Z

0

You can add the listener in this way:

class MegaButton extends ButtonElement {
  static final tag = 'mega-button';
  factory MegaButton() => new Element.tag('button', tag);

  MegaButton.created() : super.created() {
    var shadow = this.createShadowRoot();
    shadow.text = 'save';

    Element launchElement() {
      return (shadow);
    }

  }

}

void main() {

  document.registerElement(MegaButton.tag, MegaButton, extendsTag: 'button');

  DivElement myDiv = querySelector("#mydiv");
  MegaButton mbutton = new Element.tag('button', 'mega-button');
  mbutton.onClick.listen((e) => print('Thanks!'));
  myDiv.nodes.add(mbutton);


}

answered Oct 12, 2014 at 12:27

GioLaq

2,55724 silver badges27 bronze badges

Collectives™ on Stack Overflow

Add listener to custom element in DART lang

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related