CODEWITHSUNDEEP
dartdart-html
Hasan A Yousef
Hasan A Yousef

Reputation: 24948

Add listener to custom element in DART lang

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'));

Upvotes: 1

Views: 569

Answers (2)

Günter Zöchbauer
Günter Zöchbauer

Reputation: 657268

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!'));
  }
}

Upvotes: 1

GioLaq
GioLaq

Reputation: 2547

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);


}

Upvotes: 0

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