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バージョン: v8

Managing Focus

Manual Focus Management

Ionic provides a setFocus API on components such as Input, Searchbar, and Textarea that allows developers to manually set focus to an element. This API should be used in place of the autofocus attribute and called within:

  • The ionViewDidEnter lifecycle event for routing applications when a page is entered.
  • The didPresent lifecycle event for overlays when an overlay is presented.
  • The appload event for vanilla JavaScript applications when the application loads.
  • The result of a user gesture or interaction.

Why not autofocus?

The autofocus attribute is a standard HTML attribute that allows developers to set focus to an element when a page loads. This attribute is commonly used to set focus to the first input element on a page. However, the autofocus attribute can cause issues in routing applications when navigating between pages. This is because the autofocus attribute will set focus to the element when the page loads, but will not set focus to the element when the page is revisited. Learn more about the autofocus attribute in the MDN Web Docs.

Platform Restrictions

There are platform restrictions you should be aware of when using the setFocus API, including:

  1. Android requires user interaction before setting focus to an element. This can be as simple as a user tapping on the screen.
  2. Interactive elements can only focused a result of a user gesture on Mobile Safari (iOS), such as calling setFocus as the result of a button click.

Basic Usage

The example below demonstrates how to use the setFocus API to request focus on an input when the user clicks a button.

Routing

Developers can use the ionViewDidEnter lifecycle event to set focus to an element when a page is entered.

/* example.component.ts */
import { Component, ViewChild } from '@angular/core';
import { IonInput } from '@ionic/angular';

@Component({
selector: 'app-example',
templateUrl: './example.component.html',
})
export class ExampleComponent {
@ViewChild('input') input!: IonInput;

ionViewDidEnter() {
this.input.setFocus();
}
}

Overlays

Developers can use the didPresent lifecycle event to set focus to an element when an overlay is presented.

<ion-modal>
<ion-input></ion-input>
</ion-modal>

<script>
const modal = document.querySelector('ion-modal');
modal.addEventListener('didPresent', () => {
const input = modal.querySelector('ion-input');
input.setFocus();
});
</script>

Assistive Technology Focus Management

By default, Single Page Applications have no built-in way of informing screen readers that the active view has changed in a browser or webview. This means that users who rely on assistive technology do not always know if a navigation event occurred.

Developers who enable the focusManagerPriority config can delegate focus management to Ionic during page transitions. When enabled, Ionic will move focus to the correct element as specified in the config option. This will inform screen readers that a navigation event occurred.

Types

type FocusManagerPriority = 'content' | 'heading' | 'banner';

Content Types

The following table explains what each content type represents:

TypeDescriptionIonic ComponentSemantic HTML EquivalentLandmark Equivalent
contentThe main portion of the view.Contentmainrole="main"
headingThe title of the view.Titleh1role="heading" with aria-level="1"
bannerThe header of the view.Headerheaderrole="banner"
important

Developers should assign role="heading" and aria-level="1" to the primary Title on each view. Since multiple Title components can be used in a single view, Ionic does not automatically assign these attributes.

Specifying Priority

The config should be specified in order of decreasing priority. In the following example, Ionic will always focus headings to start. Ionic only proceeds to the next focus priority, banner, if a view does not have a heading:

focusManagerPriority: ['heading', 'banner'];

Implementation Notes

  • When specifying a focus priority, browsers may still move focus within that focus priority. For example, when specifying a 'content' focus priority, Ionic will move focus to the content. However, the browser may then move focus within that content to the first focusable element such as a button.
  • If none of the focus priorities are found in a view, Ionic will instead focus the view itself to ensure focus generally moves to the correct place. Browsers may then adjust focus within the view.
  • When navigating from the current view to the previous view, Ionic will move focus back to the element that presented the current view.
  • The focus manager can be overridden on a per-view basis as shown in Manual Focus Management with Routing.