javascript - 收缩垫工具栏

Question

我使用此处提供的示例来设置响应式导航栏

https://theinfogrid.com/tech/developers/angular/responsive-navbar-angular-flex-layout/

我的代码看起来很相似

<div style="height: 85vh;">

  <mat-toolbar color="primary" mat-scroll-shrink>
    <span>{{title}}</span>
    <span class="example-spacer"></span>
    <div fxShow="true" fxHide.lt-md="true">
      <!-- The following menu items will be hidden on both SM and XS screen sizes -->
      <a href="#" mat-button>Home</a>
      <a href="#" mat-button>About</a>
      <a href="#" mat-button>Services</a>
      <a href="#" mat-button>Portfolio</a>
      <a href="#" mat-button>Start</a>
      <a href="#" mat-button>FAQ</a>
      <a href="#" mat-button>Blog</a>
      <a href="#" mat-button>Contact</a>
    </div>

    <div fxShow="true" fxHide.gt-sm="true">
      <a href="#" (click)="sidenav.open()">Show Side Menu</a>
    </div>
  </mat-toolbar>

  <mat-sidenav-container fxFlexFill class="example-container">
    <mat-sidenav #sidenav fxLayout="column">
      <div fxLayout="column">
        <a (click)="sidenav.close()" href="#" mat-button>Close</a>
        <a href="#" mat-button>Home</a>
        <a href="#" mat-button>About</a>
        <a href="#" mat-button>Services</a>
        <a href="#" mat-button>Portfolio</a>
        <a href="#" mat-button>Start</a>
        <a href="#" mat-button>FAQ</a>
        <a href="#" mat-button>Blog</a>
        <a href="#" mat-button>Contact</a>
      </div>
    </mat-sidenav>
    <mat-sidenav-content fxFlexFill>

      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
      <p>Demoing some content to make this thing scroll</p>
    </mat-sidenav-content>
  </mat-sidenav-container>
</div>

我想要发生的是当我向下滚动时让 mat-toolbar 缩小，这在很多网站中都很常见，比如这个：

https://www.havealook.com.au/

我不会发布其余的 angular 5 代码，只需按照示例重新创建即可 - 它非常快。

我在这里查看了材料网站

https://material.angular.io/components/toolbar/overview

但是关于如何添加它的解释并不多，而且我对这些东西还很陌生。有谁知道我可以如何自定义它以使工具栏缩小，基于滚动？

Answer 1

2018 年 11 月更新

Angular CDK v7已ScrollDispatchModule弃用。改为使用ScrollingModule。

---

我创建了一个Stackblitz，其工具栏在向下滚动时会缩小。

主要步骤

使用CdkScrollDispatcher服务对滚动事件做出反应

1. ScrollDispatchModule在您的模块中导入。

import {ScrollDispatchModule} from '@angular/cdk/scrolling';

2. 标记滚动事件与指令相关的容器cdkScrollable，在这里mat-sidenav-content。

 <mat-sidenav-content fxFlexFill cdkScrollable>

3. 对组件中的滚动事件做出反应ngOnInit，获取scrollTop位置并在它大于某个阈值时设置一个标志：

private readonly SHRINK_TOP_SCROLL_POSITION = 50;
shrinkToolbar = false;

constructor(private scrollDispatcher: ScrollDispatcher,
            private ngZone: NgZone) { }

ngOnInit() {
  this.scrollDispatcher.scrolled()
    .pipe(
      map((event: CdkScrollable) => event.getElementRef().nativeElement.scrollTop)
    )
    .subscribe(scrollTop => this.ngZone.run(() => this.shrinkToolbar = scrollTop > this.SHRINK_TOP_SCROLL_POSITION ? true : false));
}

您需要运行它，ngZone因为默认情况下，scrolled()事件在ScrollDispatcherAngular 之外运行。没有它，ChangeDetection 将不会运行，您的模板也不会更新。

更改滚动时的工具栏布局

1. 添加一个收缩 css 类，当容器向下滚动时

<mat-toolbar color="primary" [ngClass]="{'shrink-toolbar': shrinkToolbar}">

2. 为缩小的布局定义 css 类。

.shrink-toolbar {
  height: 32px;
}

在官方文档中找到有关滚动服务的更多信息。