Glossary
| Term | Definition |
|---|---|
| AI Glasses | All-day wear, hands-free devices that provide access to information. Some have a display and some are audio-only. Equipped with speakers, a camera, and a microphone. |
| Display AI Glasses | AI Glasses with the addition of a small, private display for glanceable visuals that harmonize with audio output. |
| Jetpack Compose Glimmer | A Compose UI toolkit for building augmented Android XR experiences, optimized for Display AI Glasses. It provides components, theming, and behaviors for transparent displays. |
| Projected Activity | An Android Activity that runs on a host device (phone) but its UI and interactions are projected to a connected AI glasses device. |
| Projected Device | An XR device connected to an Android-powered device (host). Host projects the application content to the Projected device and let users interact with it. |
| GlimmerTheme | The root provider for styling tokens, including GlimmerColors, GlimmerTypography, and GlimmerShapes. |
| Additive Display | A display technology where black (#000000) is rendered as 100% transparent. UI is built by adding light to the environment. Display AI Glasses have an additive display. |
| Augmented Experiences | Android XR experiences that enhance a user's focus and presence in the real world. They are lightweight and additive, helping users while they are on-the-go |
| Visual Angle | A unit of measurement for perceived size in XR. The minimum readable text size is 0.6 degrees (approx. 18sp at 1 m). |
Prerequisites
- Mobile project should target minSDK 37 or higher. If the target SDK is lower than 37, increase the SDK to 37. AI Glasses should target API 36 or higher.
Core Constraints
- Don't: Use
MaterialThemeor Material Components. - Do: Use
GlimmerThemeand Jetpack Compose Glimmer Components.
Limitations
- Specific hardware device models or their unique capabilities are not detailed.
- Elevation: Standard Material 3 shadow or elevation modifiers are not
supported. You must use
ShadowScopeorDepthtokens from Jetpack Compose Glimmer. - Minimum Size: The absolute minimum size for readable text is 18sp (0.6°). Anything smaller will fail legibility checks.
- Text Weight: Avoid "Thin" or "Hairline" weights; they cause shimmering and aliasing on additive AR lenses.
1. Set up dependencies
- Setup Projected Activity: First you need to create a new projected activity for your AI glasses app. If the project doesn't already have one, see Create your first activity for AI glasses. Use references/projectedcontext-source.md to launch the Glasses Projected activity on the Projected Device.
- Mobile App Integration: If the project contains an existing mobile app,
you must create a new Glasses Activity dedicated to rendering Glimmer UI.
For detailed configuration, heavily reference Create your first activity
for AI glasses. If there isn't already a method to launch the Glasses
Activity, add a button to the existing mobile app UI labeled "Launch on
Glasses" that uses
ProjectedContextto launch the Glasses Activity on the glasses. Always keep this button in a highly visible location, such as an overlay Floating Action Button (FAB) or the top navigation bar, to ensure users discover the projection capability. If the glasses aren't connected, disable the button. Don't launch the Glasses Activity on the phone, only on the AI Glasses. If it makes sense to automatically launch the Glasses Activity without an explicit launch button, then do so. - UI Library: Identify if the project has the
androidx.xr.glimmer:glimmerlibrary, if not it must be added to the project. See Declaring Jetpack Compose Glimmer Dependencies to fetch the latest dependency version. - Theming: All Glimmer components must be wrapped within the
GlimmerThemecomposable to ensure correct token resolution. - Mandatory black background: AI Glasses use additive displays. Any
non-black color in the background blocks the real world. You must always
set a pure black background (
Modifier.background(Color.Black)) on the root container of your Projected Activity. - Font: The default font is Google Sans Flex. Use
androidx.xr.glimmer.googlefontslibrary with the default type styles unless otherwise specified. UsecreateGoogleSansFlexTypographyto create aTypographyinstance with the Google Sans Flex configuration. Provide thisTypographyinstance as normal throughGlimmerTheme. Use references/glimmersansflextypography-source.md for configuration. - Hardware Capabilities: Different types of AI glasses have different capabilities. To check for these at runtime, see the Check device capabilities at runtime for AI glasses.
- Hardware Permissions: To request hardware permissions like the microphone and camera, see the Request hardware permissions for AI glasses.
- Hardware Access: To use the glasses camera, sensors, or access the phone's hardware, see the Use a projected context to access AI glasses hardware.
2. Minimize and translate the UI
- For Display AI Glasses, build UI using components from the Jetpack Compose Glimmer framework.
- Use depth to communicate element priority and hierarchy.
- Design from the bottom up, trying to minimize how much of the real world you cover. Always bottom align UI to the glasses display.
- One Thing at a Time: Prioritize the user's awareness of the real world.
Show only one primary piece of information at a time (for example, using a
Stack) to minimize obstruction of the user's field of view. Avoid multiple simultaneous cards. - Color Contrast: Ensure at least a 70% tone difference between foreground and background using the HCT color space. For calculation metrics, use references/material-hct-source.md.
3. Map input controls
- Map app interactions, such as tap and swipe, to the available hardware controls on the glasses, such as the touchpad.
- Inputs are more 1-dimensional; users typically make one control input at a time.
- Avoid nesting scrolling controls.
- Jetpack Compose Glimmer components are designed to work with standard input methods, such as a tap or swipe on the AI glasses' touchpad.
- Use System Back to dismiss temporary states or detailed views.
- To add input, focus, tap, swipe to your Glasses UI, follow Focus in Jetpack
Compose Glimmer.
- For a detailed breakdown of hardware inputs, see Hardware Controls for Display AI Glasses
4. Build with Jetpack Compose Glimmer
Jetpack Compose Glimmer is the UI toolkit for building augmented experiences on Display AI Glasses.
Key Features
- Glimmer Theming: A simplified glasses-specific theme for optimal visibility.
- Pre-compatible Input: Supports tap and swipe by default.
- Pre-built Components: Provides optimized composables like
Card,ListItem,Button, etc.
Focus Management in Glimmer
- Jetpack Compose Glimmer uses a one-dimensional focus search.
- Focus movement is continuous for scrollable containers and discrete for elements like a row of buttons.
- To enable the system to automatically set initial focus, you must set the
isInitialFocusOnFocusableAvailableflag totruein your activity'sonCreatemethod. For more information on how to implement, see Focus in Jetpack Compose Glimmer.
Implementing Glimmer Styles
Glimmer styles are accessed through the GlimmerTheme object. Use
references/glimmertheme-source.md for reference.
| Category | Token | Value / Role |
|---|---|---|
| Color | primary | #9BBFFF (Focal color) |
| Color | secondary | #4C88E9 (Focal color) |
| Color | surface | #262626 (Transparent base - renders as transparent) |
| Color | outline | #606460 (3.dp border color) |
| Shape | Standard | RoundedCornerShape(36.dp) |
| Shape | Small | RoundedCornerShape(12.dp) |
Typography Scale (Google Sans Flex)
Strict default: When creating Glimmer UI you must use Google Sans Flex unless a custom brand typeface is explicitly specified. Variable Font Settings: As Google Sans Flex is a variable font, you must configure the following axes:
- Roundness (
ROND): Always set to100ffor the signature rounded appearance. - Width (
wdth): Set to100f. - Optical Size (
opsz): Set to9f. - Weight (
wght): Use specific values for different roles (Title:725f, Body:520f, Caption:650f).
| Style Name | Size / Line-Height | Weight Axis | Width | Roundness | Optical size |
|---|---|---|---|---|---|
| Title Large | 30.sp / 36.sp | 725 | 100 | 100 | 9 |
| Title Medium | 24.sp / 32.sp | 725 | 100 | 100 | 9 |
| Title Small | 20.sp / 28.sp | 725 | 100 | 100 | 9 |
| Body Large | 30.sp / 36.sp | 520 | 100 | 100 | 9 |
| Body Medium | 24.sp / 32.sp | 520 | 100 | 100 | 9 |
| Body Small | 20.sp / 28.sp | 520 | 100 | 100 | 9 |
| Caption | 18.sp / 28.sp | 650 | 100 | 100 | 9 |
Depth Levels
Simulate depth on AI glasses using shadows to establish a sense of hierarchy
through varying levels of emphasis. The Jetpack Compose Glimmer controls use
DepthEffect with 5 preset DepthEffectLevels. Use
references/deptheffect-source.md and
references/deptheffectlevels-source.md for reference.
Some examples:
| Level | Usage |
|---|---|
| level1 | Standard rest state for cards and persistent background UI. |
| level2 | Standard focus/pressed state for buttons and interactive cards. |
| ExtraSmall | 4.dp |
Implementing Jetpack Compose Glimmer Components
Cards
Cards are a fundamental surface-based container in Glimmer used to group related content, such as text, images, icons and actions into a single focal point. They establish a clear depth plane (Z-axis) in the Glasses environment, providing a stable background for text, images, and icons. Never embed a card within a List Item.
Core Implementation Logic
- Surface Hierarchy: Cards are designed to sit on a base surface or within
a list. They provide an automatic visual feedback when focused if an
onClicklambda is provided. - Interactivity:
- IF the entire Card serves as a single trigger (e.g., a media item or
a setting): THEN provide an
onClicklambda to enable focus effects. - ELSE: Leave
onClickasnullif the Card contains multiple internal interactive elements (like separate buttons or switches) to avoid focus contention.
- IF the entire Card serves as a single trigger (e.g., a media item or
a setting): THEN provide an
Technical Documentation Links
If you are creating a Glimmer Card component, read the:
- Developer Guidance: Jetpack Compose Glimmer: Cards
- API Source Code: Use references/card-source.md.
- Implementation Samples: Use references/card-samples-source.md. (Basic and Interactive Card usage)
Buttons
Buttons are the primary triggers for discrete actions in Glimmer. They are specifically optimized for the AI Glasses focus model, where a focus highlight is added when focus is moved to the button using the touchpad or other methods.
Core Implementation Logic
- There are two types of buttons to choose from in Glimmer:
- Standard buttons (Required text label with optional leading or trailing icons). Use this when there is more space in the UI, or when the meaning of the button isn't clear without text.
- Icon buttons (icon only). Only use icon buttons when the icon is clearly understandable.
- Both icon and standard buttons have default and toggle variants:
- Default (use for single actions like "buy" or "navigate")
- Toggle (use for things with selected states like mute buttons)
Technical Documentation Links
If you are creating a Glimmer Button component, read the:
- Developer Guidance: Jetpack Compose Glimmer: Buttons
- API Source Code: Use references/button-source.md.
- Implementation Samples: Use references/button-samples-source.md.
Title Chips
Chips are a pill-shaped, specialized labeling component designed to sit above a
Card or a group of content to provide a title. Use title chips to display
concise information like a short title, a name, or a status.
Guidelines and usage
- Spatial Spacing: When using a standalone
TitleChipabove content, you must useTitleChipDefaults.AssociatedContentSpacing(8.dp) to maintain the visual hierarchy. - Interactivity: Title chips are purely for informational purposes, they cannot be targeted or activated for navigation.
- Layout Always center text in a title chip. Never let the title chip go to two lines, and truncate extra words. Keep the label to three words or less.
Technical Documentation Links
If you are creating a Glimmer Title Chip component, read the:
- Developer Guidance: Jetpack Compose Glimmer: Title Chips
- API Source Code: Use references/titlechip-source.md.
- Implementation Samples: Use references/titlechip-samples-source.md. (Title Chips above group content)
Icons
Icons are visual symbols used to represent concepts, actions, or status in a concise way. In Glimmer, icons and icon buttons are optimized for the XR environment, providing clear visibility on additive displays and gaze-responsive feedback for interactive elements.
Guidelines and usage
- Sizing: Use predefined
IconSizes(e.g., Standard, Large) to ensure icons remain legible and meet the minimum touch target requirements for the XR environment. - Interactivity:
- If an icon serves as a trigger: Then you must use an
IconButtonto provide the automatic visual feedback and required tap-target padding. - ELSE: Use a standalone
Iconfor non-interactive indicators or status symbols.
- If an icon serves as a trigger: Then you must use an
- Contrast: NEVER use pure black (#000000) for icon tints; always use themed colors or standard Glimmer content colors to ensure the icon is visible against dark or real-world backgrounds.
- Icon Library The default icon library is Material Symbols with 600 weight, Rounded, Unfilled, unless otherwise specified.
Technical Documentation Links
If you are creating a Glimmer Icon component, read the:
- Developer Guidance: Jetpack Compose Glimmer: Icons
- API Source Code (Icon): Use references/icon-source.md.
- API Source Code (IconButton): Use references/iconbutton-source.md.
- API Source Code (IconSizes): Use references/iconsizes-source.md.
Lists
Lists are containers that allow you to navigate between and see multiple items on glasses. If your use case works with only seeing one item in the list at a time, use a Glimmer Stack. Use lists with a Title Chip when the list items are similar in type. Also use a Glimmer Stack if the items are of different types.
Guidelines and usage
- ListItem Slots: Use the
ListItemcomposable for rows. It provides predefined slots. Use references/listitem-source.md for reference. - Visual Consistency: When building lists of similar items, always use a
consistent background color (typically
GlimmerTheme.colors.surface) and corner radius (standard 36.dp) for every item. Don't vary these unless you are visually grouping different types of content. - Integrated Title Chips: Glimmer Lists support integrated title chips.
IF you need a section header within a list: THEN enable the
integrated title chip rather than adding a standalone
TitleChipto maintain spatial consistency. - Vertical Arrangement: ALWAYS use
verticalArrangement = Arrangement.spacedBy(20.dp)forVerticalListto ensure visual separation between items on the glasses display. - Be sure to use the default 20 dp spacing between list items unless otherwise specified.
Technical Documentation Links
If you are creating a Glimmer List component, read the:
- API Source Code (List): Use references/list-source.md.
- API Source Code (ListItem): Use references/listitem-source.md.
- API Source Code (ListState): Use references/liststate-source.md.
Stacks
A stack is a collapsed list that only displays one piece of content at a time, in a stacked visual, such as a card. If it is useful to show more than one item at a time, use the Glimmer List control. Don't use a title chip with a stack. If the items are of different types use a stack to show them. If the items are of the same type, use a list.
Guidelines and usage
Layout tips
- Stacks accept variable height items.
- Align your stack control with the bottom of the display.
- The stack control must be 66 dp taller than the tallest item in the stack, allowing room for the scrim and minimizing movement when navigating between items.
- Clipping and Layering: To ensure that items behind the top item are
correctly clipped and hidden, you must apply the
.itemDecoration(CardDefaults.shape)modifier to theCard(or relevant container) inside everyitemblock. - Depth Shadows: To maintain spatial separation and element priority,
utilize Glimmer's
ShadowScope,DepthEffect, or prescribedDepthEffectLevelsfor depth plane scaling.
Technical Documentation Links
If you are creating a Glimmer Stack component, read the:
- API Source Code (Stack): Use references/stack-source.md.
- API Source Code (StackState): Use references/stackstate-source.md.
- API Source Code (StackItemScope): Use references/stackitemscope-source.md.
Text
In Jetpack Compose Glimmer, the Text component builds off the Compose
text component, and lets you set various text properties. Be sure to choose a
style from the GlimmerTheme for your text. Modify the theme for your
application if you want custom typography.
Surface
Surface is a fundamental building block in Glimmer. Use
references/surface-source.md for reference.
A surface represents a distinct visual area or 'physical' boundary for components such as buttons and cards. Use it if you need to build a custom component.
5. Integrate with system UI
- For a detailed breakdown of notifications on AI Glasses, see Understand notification behavior for AI glasses and learn how to Start a glasses activity on display AI glasses from a notification.