Angular 使用动画时 smoothscroll 不起作用

Question

我是 Angular 的新手，尝试设置 smoothScroll：https://github.com/kavil/ng2SmoothScroll

我的视图设置如下：

<piiick-one smoothScroll offset="10" [scrollIf]="step === 1"></piiick-one>
<piiick-two *ngIf="max >= 2" smoothScroll offset="10" [scrollIf]="step === 2"></piiick-two>
<piiick-three *ngIf="max >= 3" smoothScroll offset="10" [scrollIf]="step === 3"></piiick-three>
<piiick-results *ngIf="max >= 4" smoothScroll offset="10" [scrollIf]="step === 4"></piiick-results>

组件设置如下：

export class StepsComponent implements DoCheck {
  step: number = 0;
  max: number = 0;
  private path: string;

  constructor(
    private route: ActivatedRoute
  ) {
    this.route.params.subscribe(params => this.path = params.path)
  }

  ngDoCheck() {
    switch (this.path) {
      case 'one': this.changeStep(1); break;
      case 'two': this.changeStep(2); break;
      case 'three': this.changeStep(3); break;
      case 'results': this.changeStep(4); break;
      default: this.changeStep(0); break;
    }    
  }

  private changeStep(step) {
    var current = this.step;

    this.step = step;
    if (step > current) {
      this.max = step;
    }
  }
}

应该发生的是，当路由/steps/three被调用时，它会smoothScroll到id等于[=30的div =]三个。这一直有效，直到我打开页面转换动画。

我的 app.component:

现在有了这个代码

import { Component } from '@angular/core';
import { query, style, animate, trigger, transition, group } from '@angular/animations';

const routerTransition = trigger('routerTransition', [
  transition('* => home', [
    query(':enter, :leave', style({ position: 'fixed', width:'100%' })
      , { optional: true }),
    group([
      query(':enter', [
        style({ transform: 'translateX(-100%)' }),
        animate('0.5s ease-in-out', style({ transform: 'translateX(0%)' }))
      ], { optional: true }),
      query(':leave', [
        style({ transform: 'translateX(0%)' }),
        animate('0.5s ease-in-out', style({ transform: 'translateX(100%)' }))
      ], { optional: true }),
    ])
  ]),
  transition('* => steps', [
    group([
      query(':enter, :leave', style({ position: 'fixed', width:'100%' })
      , { optional: true }),
      query(':enter', [
        style({ transform: 'translateX(100%)' }),
        animate('0.5s ease-in-out', style({ transform: 'translateX(0%)' }))
      ], { optional: true }),
      query(':leave', [
        style({ transform: 'translateX(0%)' }),
        animate('0.5s ease-in-out', style({ transform: 'translateX(-100%)' }))
      ], { optional: true }),
    ])
  ])
])

@Component({
  selector: 'piiick-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
  animations: [routerTransition]
})
export class AppComponent {
  prepareRouteTransition(outlet) {
    return outlet.activatedRouteData.state;
  }
}

当animations被注释掉时，smoothScroll起作用；但启用后，smoothScroll 不会触发。有谁知道为什么？

Answer 1

我想我找到了这个问题的答案。如果发现 post 有人在展示如何在动画完成后触发事件。所以我创建了一个 AnimationService 这样的：

import { Injectable } from '@angular/core';
import { Subject } from 'rxjs/Subject';

@Injectable()
export class AnimationService {
  private animatingSubject = new Subject<boolean>();

  animating = this.animatingSubject.asObservable();

  constructor() { }

  loading(state: boolean) {
    this.animatingSubject.next(state);
  }
}

用于设置动画状态。我创建了一个 Animations 组件，就像这样：

<div [@routerTransition]="prepareRouteTransition(outlet)" (@routerTransition.start)="handleStart()" (@routerTransition.done)="handleDone()">
  <router-outlet #outlet="outlet"></router-outlet>
</div>

这是放在我的 App.Component 中的，如下所示：

<piiick-header></piiick-header>
<piiick-animations></piiick-animations>
<piiick-spinner></piiick-spinner>

组件代码如下所示：

import { Component } from '@angular/core';
import { query, style, animate, trigger, transition, group } from '@angular/animations';

import { AnimationService } from '../../core/services/animation.service';

const routerTransition = trigger('routerTransition', [
  transition('* => home', [
    query(':enter, :leave', style({ position: 'fixed', width:'100%' })
      , { optional: true }),
    group([
      query(':enter', [
        style({ transform: 'translateX(-100%)' }),
        animate('0.5s ease-in-out', style({ transform: 'translateX(0%)' }))
      ], { optional: true }),
      query(':leave', [
        style({ transform: 'translateX(0%)' }),
        animate('0.5s ease-in-out', style({ transform: 'translateX(100%)' }))
      ], { optional: true }),
    ])
  ]),
  transition('* => steps', [
    group([
      query(':enter, :leave', style({ position: 'fixed', width:'100%' })
      , { optional: true }),
      query(':enter', [
        style({ transform: 'translateX(100%)' }),
        animate('0.5s ease-in-out', style({ transform: 'translateX(0%)' }))
      ], { optional: true }),
      query(':leave', [
        style({ transform: 'translateX(0%)' }),
        animate('0.5s ease-in-out', style({ transform: 'translateX(-100%)' }))
      ], { optional: true }),
    ])
  ])
])

@Component({
  selector: 'piiick-animations',
  templateUrl: './animations.component.html',
  styleUrls: ['./animations.component.scss'],
  animations: [routerTransition]
})
export class AnimationsComponent {
  constructor(private animationService: AnimationService) { }

  prepareRouteTransition(outlet) {
    return outlet.activatedRouteData.state;
  }

  handleStart(e) {
    this.animationService.loading(true);
  }

  handleDone(e) {
    this.animationService.loading(false);
  }
}

如您所见，当动画开始时，它会更新 AnimationService 并将动画属性设置为 true，当它完成动画时，它只会更新再次服务并将属性设置为 false。

现在只是让它与 smoothScroll 一起工作。起初我无法让它工作，然后我想这不仅仅是我必须等待的动画，还有内容；所以我在视图初始化后更新的 StepsComponent 添加了一个属性。

我将 HTML 更新为：

<div *ngIf="scrollIf">
    <piiick-one smoothScroll offset="10" [scrollIf]="step === 1"></piiick-one>
    <piiick-two *ngIf="max >= 2" smoothScroll offset="10" [scrollIf]="step === 2"></piiick-two>
    <piiick-three *ngIf="max >= 3" smoothScroll offset="10" [scrollIf]="step === 3"></piiick-three>
    <piiick-results *ngIf="max >= 4" smoothScroll offset="10" [scrollIf]="step === 4"></piiick-results>

    <piiick-navigation></piiick-navigation>
</div>

然后将代码更改为：

export class StepsComponent implements DoCheck, AfterViewInit {
  step: number = 0;
  max: number = 0;
  scrollIf: boolean = false;

  private path: string;
  private afterViewInit: boolean;
  private viewAnimating: boolean;

  constructor(
    private route: ActivatedRoute,
    private animationService: AnimationService
  ) {
    this.route.params.subscribe(params => this.path = params.path);
    this.animationService.animating.subscribe(animating => this.viewAnimating = animating);
  }

  ngAfterViewInit() {
    this.afterViewInit = true;
  }

  ngDoCheck() {
    if (this.afterViewInit) {
      switch (this.path) {
        case 'one': this.changeStep(1); break;
        case 'two': this.changeStep(2); break;
        case 'three': this.changeStep(3); break;
        case 'results': this.changeStep(4); break;
        default: this.changeStep(0); break;
      }
      this.scrollIf = this.afterViewInit && !this.viewAnimating;
    }
  }

  private changeStep(step) {
    var current = this.step;

    this.step = step;
    if (step > current) {
      this.max = step;
    }
  }
}

所以现在动画和 smoothScroll 工作了。我用这种方式遇到的唯一问题是视图在初始化之前不会显示。我不确定这是否是个问题。

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