How to load image with spinner in angular2

Question

my app got many images with descriptions. When user navigates these text is coming first and image is loading with some delay. I would like to add a spinner here. A directive which shows spinner while loading the image and shows image like

<myimgdir [src]='myimage.png'></myimgdir>

How to add spinner and track the image is loaded or not and display it?

Answer 1

I think the most easiest way is to use the onError event on the img element. You can use it Like:

<img [src]="image.src" onError="this.src='assets/my/fancy/loader.gif';">

Answer 2

In your controller, add a function to to handle the 'onLoad' event, setting the state to {loading: false}:

loading: boolean = true
onLoad() {
    this.loading = false;
}

In your template, render a loading gif (or whatever you want) while the state has loading === true, the tricky part is that you should just hide the img element with [hidden]="true/false" as opposed to prevent it from rendering so it will actually load the src, then just bind the onLoad function in your controller to the (load) event on the actual image:

<img *ngIf="loading" src="/assets/loading.gif" alt="loading" />
<img [hidden]="loading" (load)="onLoad()" src="{{ source }}" />

This solution is functionally the same as AngJobs's, but it's more declarative and a little less cumbersome IMO.

PS: Using [hidden]="boolean" instead of *ngIf is a bit of a gotcha, you should look to http://angularjs.blogspot.com/2016/04/5-rookie-mistakes-to-avoid-with-angular.html to understand why and for a solution on how to apply it safely.