ion-accordion

shadow

Accordions provide collapsible sections in your content to reduce vertical space while providing a way of organizing and grouping information. All ion-accordion components should be grouped inside ion-accordion-group components.

Basic Usage

Toggle Accordions

Which accordion is open is controlled by setting the value property on ion-accordion-group. Setting this property allows developers to programmatically expand or collapse certain accordions.

Listen for Accordion State Changes

注意

Most ionChange events emitted by other components such as Input and Textarea bubble. As a result, these events will bubble up and cause your ionChange listener on the Accordion Group to fire if the associated components are used inside of an Accordion.

When using other components that emit ionChange inside of Accordion it is recommended to have the ionChange callback on Accordion Group check the target key on the event passed to the callback to verify that ionChange is coming from the Accordion Group and not any descendants.

Developers can listen for the ionChange event to be notified when accordions expand or collapse.

Console

Console messages will appear here when logged from the example above.

Multiple Accordions

Developers can allow multiple accordions to be open at once with the multiple property.

Disabling Accordions

Individual Accordion

Individual accordions can be disabled with the disabled property on ion-accordion.

Accordion Group

The accordion group can be disabled with the disabled property on ion-accordion-group.

Readonly Accordions

Individual Accordion

Individual accordions can be disabled with the readonly property on ion-accordion.

Accordion Group

The accordion group can be disabled with the readonly property on ion-accordion-group.

Anatomy

Header

The header slot is used as the toggle that will expand or collapse your accordion. We recommend you use an ion-item here to take advantage of the accessibility and theming functionalities.

When using ion-item in the header slot, the ion-item's button prop is set to true and the detail prop is set to false. In addition, we will also automatically add a toggle icon to the ion-item. This icon will automatically be rotated when you expand or collapse the accordion. See Customizing Icons for more information.

Content

The content slot is used as the part of the accordion that is revealed or hidden depending on the state of your accordion. You can place anything here except for another ion-content instance as only one instance of ion-content should be added per page.

Customization

Expansion Styles

There are two built in expansion styles: compact and inset. This expansion style is set via the expand property on ion-accordion-group.

When expand="inset", the accordion group is given a border radius. On md mode, the entire accordion will shift down when it is opened.

Advanced Expansion Styles

You can customize the expansion behavior by styling based on the accordion's state. There are four state classes applied to ion-accordion. Styling using these classes can allow you to create advanced state transitions:

Class Name	Description
.accordion-expanding	Applied when the accordion is actively expanding
.accordion-expanded	Applied when the accordion is fully expanded
.accordion-collapsing	Applied when the accordion is actively collapsing
.accordion-collapsed	Applied when the accordion is fully collapsed

If you need to target specific pieces of the accordion, we recommend targeting the element directly. For example, if you want to customize the ion-item in your header slot when the accordion is expanded, you can use the following selector:

ion-accordion.accordion-expanding ion-item[slot="header"],
ion-accordion.accordion-expanded ion-item[slot="header"] {
  --color: red;
}

Icons

When using an ion-item in the header slot, we automatically add an ion-icon. The type of icon used can be controlled by the toggleIcon property, and the slot it is added to can be controlled with the toggleIconSlot property.

If you would like to manage the icon yourself or use an icon that is not an ion-icon, you can add the ion-accordion-toggle-icon class to the icon element.

Regardless of which option you choose, the icon will automatically be rotated when you expand or collapse the accordion.

Theming

Since ion-accordion acts as a shell around the header and content elements, you can easily theme the accordion however you would like. You can theme the header by targeting the slotted ion-item. Since you are using ion-item, you also have access to all of the ion-item CSS Variables and ion-item Shadow Parts. Theming the content is also easily achieved by targeting the element that is in the content slot.

Accessibility

Animations

By default, animations are enabled when expanding or collapsing an accordion item. Animations will be automatically disabled when the prefers-reduced-motion media query is supported and set to reduce. For browsers that do not support this, animations can be disabled by setting the animated config in your Ionic Framework app.

Keyboard Interactions

When used inside an ion-accordion-group, ion-accordion has full keyboard support for interacting with the component. The following table details what each key does:

Key	Description
Space or Enter	When focus is on the accordion header, the accordion will collapse or expand depending on the state of the component.
Tab	Moves focus to the next focusable element.
Shift + Tab	Moves focus to the previous focusable element.
Down Arrow	- When focus is on an accordion header, moves focus to the next accordion header. - When focus is on the last accordion header, moves focus to the first accordion header.
Up Arrow	- When focus is on an accordion header, moves focus to the previous accordion header. - When focus is on the first accordion header, moves focus to the last accordion header.
Home	When focus is on an accordion header, moves focus to the first accordion header.
End	When focus is on an accordion header, moves focus to the last accordion header.

Performance

Animations

The accordion animation works by knowing the height of the content slot when the animation starts. The accordion expects that this height will remain consistent throughout the animation. As a result, developers should avoid performing any operation that may change the height of the content during the animation.

For example, using ion-img may cause layout shifts as it lazily loads images. This means that as the animation plays, ion-img will load the image data, and the dimensions of ion-img will change to account for the loaded image data. This can result in the height of the content slot changing. Developers have a few options for avoiding this:

1. Use an img element without any lazy loading. ion-img always uses lazy loading, but img does not use lazy loading by default. This is the simplest option and works well if you have small images that do not significantly benefit from lazy loading.

2. Set a minimum width and height on ion-img. If you need to use lazy loading and know the dimensions of the images ahead of time (such as if you are loading icons of the same size), you can set the ion-img to have a minimum width or height using CSS. This gives developers the benefit of lazy loading while avoiding layout shifts. This works when using an img element with loading="lazy" too!

3. If neither of these options are applicable, developers may want to consider disabling animations altogether by using the animated property on ion-accordion-group.

Properties

disabled

Description	trueの場合、アコーディオンは対話することができません。
Attribute	disabled
Type	boolean
Default	false

mode

Description	modeは、どのプラットフォームのスタイルを使用するかを決定します。 This is a virtual property that is set once during initialization and will not update if you change its value after the initial render.
Attribute	mode
Type	"ios" ｜ "md"
Default	undefined

readonly

Description	trueの場合、アコーディオンはインタラクティブに操作することはできませんが、不透明度は変化しません。
Attribute	readonly
Type	boolean
Default	false

toggleIcon

Description	使用するトグルアイコンです。このアイコンは、アコーディオンの展開・折りたたみ時に回転されます。
Attribute	toggle-icon
Type	string
Default	chevronDown

toggleIconSlot

Description	トグルアイコンを配置する ion-item の内側のスロット。デフォルトは "end" です。
Attribute	toggle-icon-slot
Type	"end" ｜ "start"
Default	'end'

value

Description	アコーディオンの値です。デフォルトは自動生成された値です。
Attribute	value
Type	string
Default	ion-accordion-${accordionIds++}

Events

No events available for this component.

Methods

No public methods available for this component.

CSS Shadow Parts

Name	Description
content	content slotのラッパー要素。
expanded	拡張された要素です。ヘッダとコンテンツの部分と組み合わせて使用することができます（例：::part(header expanded)）。
header	header slotのラッパーの要素です。

CSS Custom Properties

No CSS custom properties available for this component.

Slots

Name	Description
content	コンテンツはヘッダーの下に配置され、展開状態に応じて表示または非表示になります。
header	コンテンツは上部に配置され、アコーディオンアイテムの拡大・縮小に使用されます。