如何根据角度2中的按钮单击移动div滚动位置

Question

在app.component.html文件中,我有一个带水平滚动的div元素和两个按钮作为Next和Previous.基于这些按钮单击我想移动滚动.

app.component.html

<div id="th-infinite-scroll-tracker" style="overflow-y:scroll; height: 200px;" scrollTracker (scroll)="onScroll($event)" (mouseup)="searchLog($event)">
        <div *ngFor="let log of arr; let i = index" innerHTML="{{log}}" [id]="i"></div>
</div>
<button (click)="onPreviousSearchPosition()" [disabled]="disablePreviousBtn">Previous</button>
<button (click)="onNextSearchPosition()" [disabled]="disableNextBtn">Next</button>

app.component.ts

@HostListener('scroll', ['$event'])
onScroll(event){
    this.scrollObject = event;
}
onPreviousSearchPosition(){
    this.disableNextBtn = false;

    this.scrollObject.target.scrollTop = 20 * --this.idCount;
  }
onPreviousNextPosition(){
    this.disableNextBtn = false;

    this.scrollObject.target.scrollTop = 20 * ++this.idCount;
  }

使用上面的代码我们可以移动滚动但我们需要滚动事件对象,它将在手动滚动后得到.请建议我,如何在组件类中创建滚动事件对象

Answer 1

这是滚动div元素的方法 - https://plnkr.co/edit/2v0iVgkOZfISqlFAkrNX?p=preview

例:

import { Component, ViewChild, ElementRef } from '@angular/core';
@Component({
  selector: 'my-app',
  template: `
    <div #panel style="overflow-y:scroll; height: 20px;" >
      <div *ngFor="let log of arr; let i = index" innerHTML="{{log}}" [id]="i"></div>
    </div>
    <button (click)="onPreviousSearchPosition()">Previous</button>
    <button (click)="onNextSearchPosition()">Next</button>
  `
})
export class AppComponent { 
  public arr = ['foo', 'bar', 'baz'];
  @ViewChild('panel', { read: ElementRef }) public panel: ElementRef<any>;

  public onPreviousSearchPosition(): void {
    this.panel.nativeElement.scrollTop -= 20;
  }

  public onNextSearchPosition(): void {
    this.panel.nativeElement.scrollTop += 20;
  }
}

Answer 2

我更愿意使用scrollIntoView()方法.当我们点击相应的元素时,此方法在浏览器中提供平滑的滚动过渡效果.

    @Component({
    selector: 'my-app',
    template: `
      <div #panel class="some-class">
        <div *ngFor="let log of arr; let i = index" innerHTML="{{log}}" [id]="i"></div>
      </div>
      <button (click)="moveToSpecificView()">Move</button>
    `
})
export class AppComponent {
    public arr = ['foo', 'bar', 'baz'];
    @ViewChild('panel') public panel:ElementRef;

    public moveToSpecificView()(): void {
        setTimeout(() => {
            this.panel.nativeElement.scrollIntoView({ behavior: 'smooth', block: 'end', inline: 'start' });
        });
    }

  }