Overview for expansion
<mat-expansion-panel>
provides an expandable details-summary view.
This is the primary content of the panel.
I'm visible because I am open
Expansion-panel content
Header
The <mat-expansion-panel-header>
shows a summary of the panel content and acts
as the control for expanding and collapsing. This header may optionally contain an
<mat-panel-title>
and an <mat-panel-description>
, which format the content of the
header to align with Material Design specifications.
<mat-expansion-panel hideToggle>
<mat-expansion-panel-header>
<mat-panel-title> This is the expansion title </mat-panel-title>
<mat-panel-description> This is a summary of the content </mat-panel-description>
</mat-expansion-panel-header>
<p>This is the primary content of the panel.</p>
</mat-expansion-panel>
By default, the expansion-panel header includes a toggle icon at the end of the
header to indicate the expansion state. This icon can be hidden via the
hideToggle
property.
<mat-expansion-panel hideToggle>
Action bar
Actions may optionally be included at the bottom of the panel, visible only when the expansion is in its expanded state.
<mat-action-row>
<button mat-button (click)="nextStep()">Next</button>
</mat-action-row>
Disabling a panel
Expansion panels can be disabled using the disabled
attribute. A disabled expansion panel can't
be toggled by the user, but can still be manipulated programmatically.
<mat-expansion-panel disabled>
Accordion
Multiple expansion-panels can be combined into an accordion. The multi="true"
input allows the
expansions state to be set independently of each other. When multi="false"
(default) just one
panel can be expanded at a given time:
<mat-accordion class="example-headers-align" multi>
Lazy rendering
By default, the expansion panel content will be initialized even when the panel is closed.
To instead defer initialization until the panel is open, the content should be provided as
an ng-template
:
<mat-expansion-panel>
<mat-expansion-panel-header>
This is the expansion title
</mat-expansion-panel-header>
<ng-template matExpansionPanelContent>
Some deferred content
</ng-template>
</mat-expansion-panel>
Accessibility
MatExpansionPanel
imitates the experience of the native <details>
and <summary>
elements.
The expansion panel header applies role="button"
and the aria-controls
attribute with the
content element's ID.
Because expansion panel headers are buttons, avoid adding interactive controls as children
of <mat-expansion-panel-header>
, including buttons and anchors.