我的Polymer元素中有一个纸质对话框。我想让背景不透明，现在它是半透明的。我也想改变颜色。
有谁知道怎么做。我已经在自定义元素中尝试了这个css：
<style is="custom-style">
--iron-overlay-backdrop-opacity:1;
</style>
<paper-dialog modal></paper-dialog>
但它没有效果。
我也试过了
<style is="custom-style">
:host {
--iron-overlay-backdrop-opacity:1;
}
</style>
<paper-dialog modal></paper-dialog>
iron-overlay-backdrop直接附加到文档正文中，位于自定义元素之外，并且由于Polymer的CSS封装，您无法使用元素内的<style>为背景设置样式。
但是，您的元素可以使用Polymer.updateStyles(...)对背景进行必要的样式设置，iron-overlay-backdrop会更新所有自定义元素的样式，包括元素外部的Polymer.updateStyles({
'--iron-overlay-backdrop-background-color': 'red',
'--iron-overlay-backdrop-opacity': '1'
});
：
<head>
<base href="https://polygit.org/polymer+1.11.1/components/">
<script src="webcomponentsjs/webcomponents-lite.js"></script>
<link rel="import" href="polymer/polymer.html">
<link rel="import" href="paper-button/paper-button.html">
<link rel="import" href="paper-dialog/paper-dialog.html">
</head>
<body>
<div>Click button for dialog</div>
<x-demo></x-demo>
<dom-module id="x-demo">
<template>
<x-dialog id="blue" backdrop-color="blue" backdrop-opacity="1"></x-dialog>
<x-dialog id="red" backdrop-color="red" backdrop-opacity="0.2"></x-dialog>
<x-dialog id="green" backdrop-color="green" backdrop-opacity="0.5"></x-dialog>
<paper-button on-tap="_openDialog" data-dialog="blue">Blue (opacity 100%)</paper-button>
<paper-button on-tap="_openDialog" data-dialog="red">Red (opacity 20%)</paper-button>
<paper-button on-tap="_openDialog" data-dialog="green">Green (opacity 50%)</paper-button>
</template>
<script>
HTMLImports.whenReady(function() {
Polymer({
is: 'x-demo',
_openDialog: function(e) {
var dialog = e.target.dataset.dialog;
this.$[dialog].opened = true;
}
})
});
</script>
</dom-module>
<dom-module id="x-dialog">
<template>
<paper-dialog modal with-backdrop opened="{{opened}}">
<div class="buttons">
<paper-button dialog-dismiss>Close</paper-button>
</div>
</paper-dialog>
</template>
<script>
HTMLImports.whenReady(function() {
Polymer({
is: 'x-dialog',
properties: {
backdropColor: {
type: String,
value: 'green'
},
backdropOpacity: {
type: String,
value: '0.6'
},
opened: {
type: Boolean,
value: false
}
},
observers: ['_updateBackdrop(opened, backdropColor, backdropOpacity)'],
_updateBackdrop: function(opened, color, opacity) {
if (opened && color && opacity) {
Polymer.RenderStatus.afterNextRender(this, function() {
this._setBackdropStyles(color, opacity);
});
}
},
_setBackdropStyles: function(color, opacity) {
Polymer.updateStyles({
'--iron-overlay-backdrop-background-color': color,
'--iron-overlay-backdrop-opacity': opacity
});
}
});
});
</script>
</dom-module>
</body><style is="custom-style">
或者要为所有背景设置固定的静态样式，请使用正文中的<body>
<style is="custom-style">
iron-overlay-backdrop {
--iron-overlay-backdrop-opacity: 1;
--iron-overlay-backdrop-background-color: green;
}
</style>
<x-dialog></x-dialog>
</body>
：
<head>
<base href="https://polygit.org/polymer+1.11.1/components/">
<script src="webcomponentsjs/webcomponents-lite.js"></script>
<link rel="import" href="polymer/polymer.html">
<link rel="import" href="paper-button/paper-button.html">
<link rel="import" href="paper-dialog/paper-dialog.html">
</head>
<body>
<style is="custom-style">
iron-overlay-backdrop {
--iron-overlay-backdrop-opacity: 1;
--iron-overlay-backdrop-background-color: green;
}
</style>
<div>Hello world</div>
<x-dialog></x-dialog>
<dom-module id="x-dialog">
<template>
<paper-dialog modal with-backdrop opened>
<div class="buttons">
<paper-button dialog-dismiss>Close</paper-button>
</div>
</paper-dialog>
</template>
<script>
HTMLImports.whenReady(function() {
Polymer({ is: 'x-dialog' });
});
</script>
</dom-module>
</body>qazxswpoi