動態更改應用程序標題（聚合物）的backgorund圖像

Question

的應用頭的造型看起來像這樣

app-header { 
    position: fixed; 
    top: 0; 
    left: 0; 
    width: 100%; 
    height: 212px; 
    color: #fff; 
    background-color: #3f51b5; 
    --app-header-background-front-layer: { 
    background-image: url(//app-layout-assets.appspot.com/assets/bg1.jpg); 
    background-position: left center; 
    }; 
} 




<app-header condenses reveals effects="waterfall resize-title blend-background parallax-background"> 
    <app-toolbar> 
    <paper-icon-button icon="menu"></paper-icon-button> 
    <h4 condensed-title>What is material? &mdash; Environment</h4> 
    <paper-icon-button icon="search"></paper-icon-button> 
</app-toolbar> 
<app-toolbar class="tall"> 
    <h1 main-title>What is material?</h1> 
</app-toolbar> 

如何動態地更改背景圖片的URL，並在javascript我自己掉了嗎？

Answer 1

HREF $ = 「{{imgUrl的}}」

使用所計算的屬性或觀察者改變圖像。

保重