mirror of
https://github.com/material-components/material-components-android.git
synced 2026-02-20 08:39:55 +08:00
130 lines
7.6 KiB
Markdown
130 lines
7.6 KiB
Markdown
<!--docs:
|
|
title: "Badge"
|
|
layout: detail
|
|
section: components
|
|
excerpt: "Badges can contain dynamic information, such as a number of pending requests."
|
|
iconId: badge
|
|
path: /catalog/badging/
|
|
-->
|
|
|
|
# `BadgeDrawable`
|
|
|
|
## Design & API Documentation
|
|
|
|
* [Google Material3 Spec](https://material.io/components/badges/overview)
|
|
* [API reference](https://developer.android.com/reference/com/google/android/material/badge/package-summary)
|
|
|
|
## Using badges
|
|
|
|
Badge | Badge with number | Badge with a maximum character count
|
|
--------------------------------------------- | ---------------------------------------------------- | ------------------------------------
|
|
 |  | 
|
|
|
|
**Note:** This component is still under development and may not support the full
|
|
range of customization Material Android components generally support, for
|
|
instance, themed attributes.
|
|
|
|
A `BadgeDrawable` represents dynamic information such as a number of pending
|
|
requests in a [`BottomNavigationView`](BottomNavigation.md) or
|
|
[`TabLayout`](Tabs.md).
|
|
|
|
## Usage
|
|
|
|
API and source code:
|
|
|
|
* `BadgeDrawable`
|
|
* [Class definition](https://developer.android.com/reference/com/google/android/material/badge/BadgeDrawable)
|
|
* [Class source](https://github.com/material-components/material-components-android/tree/master/lib/java/com/google/android/material/badge/BadgeDrawable.java)
|
|
* `BadgeUtils`
|
|
* [Class definition](https://developer.android.com/reference/com/google/android/material/badge/BadgeUtils)
|
|
* [Class source](https://github.com/material-components/material-components-android/tree/master/lib/java/com/google/android/material/badge/BadgeUtils.java)
|
|
|
|
Create an instance of `BadgeDrawable` by calling `create(Context)` or
|
|
`createFromAttributes(Context, AttributeSet, int, int)}`.
|
|
|
|
The approach used to add and display a `BadgeDrawable` on top of its anchor view
|
|
depends on the API level:
|
|
|
|
In API 18+ (APIs supported by
|
|
[ViewOverlay](https://developer.android.com/reference/android/view/ViewOverlay))
|
|
|
|
1. Add `BadgeDrawable` as a
|
|
[ViewOverlay](https://developer.android.com/reference/android/view/ViewOverlay)
|
|
to the desired anchor view.
|
|
2. Update the `BadgeDrawable`'s coordinates (center and bounds) based on its
|
|
anchor view using `#updateBadgeCoordinates(View)`.
|
|
|
|
Both steps have been encapsulated in a util method:
|
|
|
|
```java
|
|
BadgeUtils.attachBadgeDrawable(badgeDrawable, anchor);
|
|
```
|
|
|
|
In Pre API-18
|
|
|
|
1. Set `BadgeDrawable` as the foreground of the anchor view's `FrameLayout`
|
|
ancestor.
|
|
2. Update the `BadgeDrawable`'s coordinates (center and bounds) based on its
|
|
anchor view, relative to its `FrameLayout` ancestor's coordinate space.
|
|
|
|
Option 1: `BadgeDrawable` will dynamically create and wrap the anchor view in a
|
|
`FrameLayout`, then insert the `FrameLayout` into the original anchor view
|
|
position in the view hierarchy. Same syntax as API 18+
|
|
|
|
```java
|
|
BadgeUtils.attachBadgeDrawable(badgeDrawable, anchor);
|
|
```
|
|
|
|
Option 2: If you do not want `BadgeDrawable` to modify your view hierarchy, you
|
|
can specify a `FrameLayout` to display the badge instead.
|
|
|
|
```java
|
|
* BadgeUtils.attachBadgeDrawable(badgeDrawable, anchor, anchorFrameLayoutParent);
|
|
```
|
|
|
|
### `BadgeDrawable` Gravity Modes
|
|
|
|
`BadgeDrawable` offers two gravity modes to control how the badge aligns with
|
|
its anchor view. By default, (`TOP_END`) badge aligns with the top and end edges
|
|
of the anchor (with some offsets). Alternatively, you can use `TOP_START` to
|
|
align the badge with the top and start edges of the anchor. Note that
|
|
`BOTTOM_START` and `BOTTOM_END` are deprecated and not recommended for use.
|
|
|
|
### `BadgeDrawable` center offsets
|
|
|
|
By default, `BadgeDrawable` is aligned with the top and end edges of its anchor
|
|
view (with some offsets if `offsetAlignmentMode` is `legacy`). Call `setBadgeGravity(int)` to change it to one of the
|
|
other supported modes. To adjust the badge's offsets relative to the anchor's
|
|
center, use `setHorizontalOffset(int)` or `setVerticalOffset(int)`
|
|
|
|
### `BadgeDrawable` Attributes
|
|
|
|
| Feature | Relevant attributes |
|
|
|----------------------- |----------------------------------------------------------------------------------------------------------------------------------------------------------|
|
|
| Color | `app:backgroundColor` <br> `app:badgeTextColor` |
|
|
| Width | `app:badgeWidth` <br> `app:badgeWithTextWidth` |
|
|
| Height | `app:badgeHeight` <br> `app:badgeWithTextHeight` |
|
|
| Shape | `app:badgeShapeAppearance` <br> `app:badgeShapeAppearanceOverlay` <br> `app:badgeWithTextShapeAppearance` <br> `app:badgeWithTextShapeAppearanceOverlay` |
|
|
| Label | `app:badgeText` (for text) <br> `app:number` (for numbers) |
|
|
| Label Length | `app:maxCharacterCount` (for all text) <br> `app:maxNumber` (for numbers only) |
|
|
| Label Text Color | `app:badgeTextColor` |
|
|
| Label Text Appearance | `app:badgeTextAppearance` |
|
|
| Badge Gravity | `app:badgeGravity` |
|
|
| Offset Alignment | `app:offsetAlignmentMode` |
|
|
| Horizontal Padding | `app:badgeWidePadding` |
|
|
| Vertical Padding | `app:badgeVerticalPadding` |
|
|
| Large Font Vertical Offset| `app:largeFontVerticalOffsetAdjustment` |
|
|
| Auto Adjust | `app:autoAdjustToWithinGrandparentBounds` |
|
|
|
|
**Note:** If both `app:badgeText` and `app:number` are specified, the badge label will be `app:badgeText`.
|
|
|
|
### Talkback Support
|
|
|
|
`BadgeDrawable` provides a getter for its content description, which is based on the displayed
|
|
number or text (if any). To specify the content description, the developer is provided
|
|
with the following methods:
|
|
- `setContentDescriptionForText(CharSequence)`
|
|
- `setContentDescriptionQuantityStringsResource(@PluralsRes int)`
|
|
- `setContentDescriptionExceedsMaxBadgeNumberStringResource(@StringRes int)`
|
|
- `setContentDescriptionNumberless(CharSequence)`
|