I have transform basic html page with bootstrap scrollspy component and my nav doesn't work (no change when page scroll).
I have install bootstrap 4 with the command below :
npm install bootstrap
There is no change on page scroll or when i click on menu there is no "active" flag.
Can you help me ? Thanks :)
check the solution here using a directive
for spyScroll
. It listens to scroll event on the page and highlights the current section in view.
import { Directive, Injectable, Input, EventEmitter, Output, ElementRef, HostListener } from '@angular/core';
@Directive({
selector: '[scrollSpy]'
})
export class ScrollSpyDirective {
@Input() public spiedTags = [];
@Output() public sectionChange = new EventEmitter<string>();
private currentSection: string;
constructor(private _el: ElementRef) {}
@HostListener('scroll', ['$event'])
onScroll(event: any) {
let currentSection: string;
const children = this._el.nativeElement.children;
const scrollTop = event.target.scrollTop;
const parentOffset = event.target.offsetTop;
for (let i = 0; i < children.length; i++) {
const element = children[i];
if (this.spiedTags.some(spiedTag => spiedTag === element.tagName)) {
if ((element.offsetTop - parentOffset) <= scrollTop) {
currentSection = element.id;
}
}
}
if (currentSection !== this.currentSection) {
this.currentSection = currentSection;
this.sectionChange.emit(this.currentSection);
}
}
}
In AppComponent:
import { Component } from '@angular/core';
@Component({
selector: 'my-app',
templateUrl: './app.component.html',
styleUrls: [ './app.component.css' ]
})
export class AppComponent {
currentSection = 'section1';
onSectionChange(sectionId: string) {
this.currentSection = sectionId;
}
scrollTo(section) {
document.querySelector('#' + section)
.scrollIntoView();
}
}
AppComponent.html:
<h1>Current Section : [{{currentSection}}]</h1>
<h2>Menu</h2>
<div (click)="scrollTo('section1')" [ngClass]="{ 'current-section': currentSection === 'section1' }">Section 1
</div>
<div (click)="scrollTo('section2')" [ngClass]="{ 'current-section': currentSection === 'section2' }">Section 2
</div>
<div (click)="scrollTo('section3')" [ngClass]="{ 'current-section': currentSection === 'section3' }">Section 3
</div>
<div (click)="scrollTo('section4')" [ngClass]="{ 'current-section': currentSection === 'section4' }">Section 4
</div>
<br/>
<div id="parentDiv" scrollSpy [spiedTags]="['DIV']" (sectionChange)="onSectionChange($event)" style="height:150px;overflow-y: scroll;">
<div id="section1">
<h2 style="margin:0">Section 1</h2>
<lorem-ipsum></lorem-ipsum>
</div>
<div id="section2">
<h1>Section 2</h1>
<lorem-ipsum></lorem-ipsum>
</div>
<div id="section3">
<h1>Section 3</h1>
<lorem-ipsum></lorem-ipsum>
</div>
<div id="section4">
<h1>Section 4</h1>
<lorem-ipsum></lorem-ipsum>
</div>
</div>
<br/>
In app.component.css:
.current-section {
background-color: cornflowerblue
}
.current-section::after {
content: "\039e";
background-color: yellow;
color: red;
}