我为bootstrap 4添加了我的angular 6项目,并创建了导航栏,导航栏工作良好,但是当向下滚动更改导航栏徽标时,我试图更改它,但我遇到了一些冲突,但是我不知道该怎么做正确地放在角上。 任何人都知道如何解决该问题。
谢谢
标题代码部分
<header class="main_menu home_menu">
<div class="container">
<div class="row align-items-center">
<div class="col-lg-12">
<nav class="navbar navbar-expand-lg navbar-light">
<a class="navbar-brand" > <img src="https://www.seeklogo.net/wp-content/uploads/2012/12/apple-logo-eps-logo-vector-400x400.png" style="width:50px;"> </a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button></nav>
</div></div></div></header>
答案 0 :(得分:2)
我已经创建了Stackblitz。
我正在监听scroll
事件,并向HTML的img
标签添加了绑定。
TS
export class AppComponent {
name = 'Angular';
logoPath = 'https://via.placeholder.com/150/0000FF/808080?Text=oldLogo'
ngOnInit() {
window.addEventListener("scroll", this.scroll, true); //third parameter
}
scroll = () => {
const scrollPos = document.documentElement.scrollTop;
// change '50' according to when you want to change the image
if (scrollPos > 50) {
console.log('New image');
this.logoPath = 'https://via.placeholder.com/150/FF00FF/808080?Text=newLogo';
}
else {
console.log('Old Image');
this.logoPath = 'https://via.placeholder.com/150/0000FF/808080?Text=oldLogo';
}
};
}
HTML
<nav class="navbar navbar-expand-lg navbar-light fixed-top">
<a class="navbar-brand" > <img [src]="logoPath" ...