PopupButton

A convenient shortcut for looking up an element by ID in the component's Shadow DOM subtree.

Example: if component's template contains a shadow element <button id="foo">, you can use the reference this.$.foo to obtain the corresponding button in the component instance's shadow tree. The $ function is simply a shorthand for getElementById, so this.$.foo is the same as this.shadowRoot.getElementById('foo').

The class, tag, or template used for the optional backdrop element behind the overlay.

This can help focus the user's attention on the overlay content. Additionally, a backdrop can be used to absorb clicks on background page elements. For example, Dialog uses ModalBackdrop as an overlay backdrop in such a way.

Close the component (if not already closed).

Some components like AlertDialog want to indicate why or how they were closed. To support such scenarios, you can supply a value to the optional closeResult parameter. This closeResult will be made available in the whenClosed promise and the state.closeResult member.

True if the element is currently closed.

Raised when the component closes.

True if the element has completely closed.

For components not using asynchronous open/close effects, this property returns the same value as the closed property. For elements that have a true value of state.openCloseEffects (e.g., elements using TransitionEffectMixin), this property returns true only if state.effect is "close" and state.effectPhase is "after".

The default state for the component. This can be extended by mixins and classes to provide additional default state.

True if the component is disabled, false (the default) if not.

The value of this property will be reflected to the disabled attribute so that it can be referenced in CSS. Note that this non-native implementation of the disabled attribute will not trigger the :disabled CSS pseudo-class, so your style rules will have to reference the presence or absence of the disabled attribute. That is, instead of writing

my-component:disabled { ... }

write this instead

my-component[disabled] { ... }

Like the native disabled attribute, this attribute is boolean. That means that it's existence in markup sets the attribute, even if set to an empty string or a string like "false".

The class, tag, or template used to contain the popup content.

The frame element can be used to provide a border around the popup content, and to provide visual effects such as a drop-shadow to help distinguish popup content from background page elements.

The alignment of the popup with respect to the source button.

• start: popup and source are aligned on the leading edge according to the text direction
• end: popup and source are aligned on the trailing edge according to the text direction
• left: popup and source are left-aligned
• right: popup and source are right-aligned
• `stretch: both left and right edges are aligned

Open the element (if not already opened).

True if the element is currently opened.

Raised when the component opens.

Raised when the opened/closed state of the component changes.

The preferred direction for the popup.

• above: popup should appear above the source
• below: popup should appear below the source

The class, tag, or template used to define the popup.

The popup element is responsible for handling overlay behavior.

Render the component to the DOM.

This method does nothing if the state has not changed since the last render call.

This method invokes all internal render methods. It then invoked componentDidMount (for first render) or componentDidUpdate (for subsequent renders).

Update the component's state by merging the specified changes on top of the existing state. If the component is connected to the document, and the new state has changed, this returns a promise to asynchronously render the component. Otherwise, this returns a resolved promise.

Return true if the component should update.

By default, ReactiveMixin will perform a shallow check of property values like React's PureComponent. This seems adequate for most web components. You can override this to always return true (like React's base Component class), or to perform more specific, deeper checks for changes in state.

The class, tag, or template used for the button (or other element) that will invoke the popup.

The component's current state. The returned state object is immutable. To update it, invoke setState.

Temporarily suppress visibility of the keyboard focus until the next keydown event.

This can be useful in components like Menu that actively manage where the focus is in response to mouse hover activity. If the user uses the keyboard to invoke a menu, then changes to using the mouse, it can be distracting to see the focus indicator moving as well. In such situations, the component can invoke this method (e.g., in response to mousemove) to temporarily suppress focus visibility.

See the symbols documentation for details.

Toggle the open/close state of the element.

The attributes and properies that should be applied to the component on render. By default, this is an empty plain object. Your mixin or component can extend this to identify the properties to set on the host element or elements in the shadow subtree.

This method can be used as an alternative to listening to the "opened-changed" event, particularly in situations where you want to only handle the next time the component is closed.