問(wèn)題描述

我想在 div 中顯示一個(gè)背景圖像/加載微調(diào)器，它將在其中加載一個(gè)圖像，圖像將在完全加載后顯示，執(zhí)行如下操作:

I want to show a background image/loading spinner inside a div that will load an image inside of it, the image will show once it's fully loaded doing something like this:

   <div style="background-image:url('imageThatWillAppearBeforeLoad')"></div>

演示(在 jQuery 中)

如何使用 Angular2/Ionic2 獲得相同的效果?

How can I have the same using Angular2/Ionic2?

推薦答案

創(chuàng)建一個(gè)組件，在加載請(qǐng)求的圖像之前顯示占位符圖像，并隱藏請(qǐng)求的圖像.加載圖像后，隱藏占位符并顯示圖像.

Create a component that shows the placeholder image until the requested image is loaded, and hides the requested image. Once the image is loaded, you hide the placeholder and show the image.

@Component({
  selector: 'image-loader',
  template: `<img *ngIf="!loaded" src="url-to-your-placeholder"/>
    <img [hidden]="!loaded" (load)="loaded = true" [src]="src"/>`
})
export class ImageLoader {
  @Input() src;
}

查看它在 Plunker 中的工作.

See it working in Plunker.

更新

現(xiàn)在我更好地理解了要求，這里有一個(gè)帶有背景圖片的解決方案.有點(diǎn)hacky，我更喜歡原來(lái)的...

Now that I understand the requirements better, here's a solution with background image. It's a little hacky, and I like the original one better...

@Directive({
  selector: '[imageLoader]'
})
export class ImageLoader {
  @Input() imageLoader;

  constructor(private el:ElementRef) {
    this.el = el.nativeElement;
    this.el.style.backgroundImage = "url(http://smallenvelop.com/demo/image-loading/spinner.gif)";
  }

  ngOnInit() {
    let image = new Image();
    image.addEventListener('load', () => {
      this.el.style.backgroundImage = `url(${this.imageLoader})`;
    });
    image.src = this.imageLoader;
  }
}

更新插件.

這篇關(guān)于加載圖像時(shí)顯示加載圖標(biāo)的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！