我想在Polymer-gestures的Polymer自定义元素上添加listener事件 .
这是我的示例代码：
- my-custom-element.html
<link rel="import" href="../polymer/polymer.html">
<polymer-element name="my-custom-element" attributes="width height color">
<template>
<canvas id="canvas" width="{{width}}" height="{{height}}" style="background-color: {{color}}" touch-action="none"></canvas>
</template>
<script>
Polymer({
width: '',
height: '',
color: ''
});
</script>
</polymer-element>
- my-custom-parent-element.html
<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../polymer-gestures/polymer-gestures.html">
<polymer-element name="my-custom-parent-element">
<template>
<my-custom-element width="300px" height="200px" color="yellow"></my-custom-element>
</template>
<script>
Polymer({
ready: function() {
this.myCustomElement = this.shadowRoot.querySelector('my-custom-element');
var events = [
// base events
'down',
'up',
'trackstart',
'track',
'trackend',
'tap',
'hold',
'holdpulse',
'release'
];
events.forEach(function(en) {
PolymerGestures.addEventListener(this.myCustomElement, en, function (inEvent) {
...
});
}
});
</script>
</polymer-element>
我有这样的错误
未捕获的TypeError：无法读取未定义的属性'_pgListeners'
在调试模式下，当我在my-custom-parent-element.html中添加事件监听器时，我检查了myCustomElement变量的值，它是null .
我怎么能在myCustomElement变量上添加事件监听器???
1 回答
以下行中的querySelector拼写错误：
试试
this.shadowRoot.querySelector('my-custom-element');.