功能和 API 概览

Android 14 面向开发者引入了一些出色的功能和 API。以下内容可帮助您了解适用于您的应用的功能并开始使用相关 API。

如需查看新增、修改和移除的 API 的详细列表，请参阅 API 差异报告。如需详细了解添加的 API，请访问 Android API 参考文档。对于 Android 14，请查找在 API 级别 34 中添加的 API。如需了解平台变更可能会在哪些方面影响您的应用，请务必查看会影响以 Android 14 为目标平台的应用和所有应用的 Android 14 行为变更。

国际化

单个应用语言设置

Android 14 expands on the per-app language features that were introduced in Android 13 (API level 33) with these additional capabilities:

  • Automatically generate an app's localeConfig: Starting with Android Studio Giraffe Canary 7 and AGP 8.1.0-alpha07, you can configure your app to support per-app language preferences automatically. Based on your project resources, the Android Gradle plugin generates the LocaleConfig file and adds a reference to it in the final manifest file, so you no longer have to create or update the file manually. AGP uses the resources in the res folders of your app modules and any library module dependencies to determine the locales to include in the LocaleConfig file.

  • Dynamic updates for an app's localeConfig: Use the setOverrideLocaleConfig() and getOverrideLocaleConfig() methods in LocaleManager to dynamically update your app's list of supported languages in the device's system settings. Use this flexibility to customize the list of supported languages per region, run A/B experiments, or provide an updated list of locales if your app utilizes server-side pushes for localization.

  • App language visibility for input method editors (IMEs): IMEs can utilize the getApplicationLocales() method to check the language of the current app and match the IME language to that language.

Grammatical Inflection API

有 30 亿人在使用区分性别的语言，此类语言的语法类别（例如名词、动词、形容词和介词）会根据您交谈所涉及的人或物的性别而变化。传统上，许多区分性别的语言使用阳性语法性别作为默认或通用性别。

以错误的语法性别来称呼用户，例如以阳性语法性别来称呼女性，可能会对她们的表现和态度产生负面影响。相比之下，界面语言如果能正确反映用户的语法性别，就可以提高用户互动度，并提供更个性化、更自然的用户体验。

为帮助您针对区分性别的语言构建以用户为中心的界面，Android 14 引入了 Grammatical Inflection API，让您无需重构应用便能添加对语法性别的支持。

地区偏好设置

用户可通过地区偏好设置对温度单位、一周的第一天和编号系统进行个性化设置。居住在美国的欧洲用户可能更希望使用摄氏度，而不是华氏度，并且希望应用将星期一视为一周的开始，而不是像美国那样默认从星期日开始。

新 Android 设置菜单包含这些偏好设置，使用户能够在一个位置集中发现这些应用更改偏好设置。这些偏好设置在备份和恢复设备后也会保持不变。多个 API 和 intent（例如 getTemperatureUnit 和 getFirstDayOfWeek）会为您的应用授予读取权限来访问用户偏好设置，因此您的应用可以调整其显示信息的方式。您还可以在 ACTION_LOCALE_CHANGED 上注册 BroadcastReceiver，以便在地区偏好设置发生更改时处理语言区域配置更改。

如需找到这些设置，请打开“设置”应用，然后依次前往系统 > 语言和输入法 > 地区偏好设置。

Android 系统设置中的地区偏好设置界面。
Android 系统中地区偏好设置的温度选项 设置。

无障碍

非线性字体放大至 200%

从 Android 14 开始，系统支持字体放大高达 200%，为用户提供了其他无障碍功能选项。

为防止屏幕上的大文本元素过于放大，系统会采用非线性放大曲线。这种放大策略意味着大号文本的放大比例不会与较小的文本相同。非线性字体放大有助于保持不同大小元素之间的比例层次结构，同时缓解高级别线性文本放大存在的问题（例如文本被截断或文本因非常大的显示大小而难以阅读）。

使用非线性字体放大测试应用

在设备的无障碍设置中启用最大字号，以测试应用。

如果您已使用可缩放像素 (sp) 单位来定义文本大小，那么这些额外的选项和缩放改进会自动应用于应用中的文本。不过，您仍应在启用最大字体大小 (200%) 的情况下执行界面测试，以确保应用正确应用字体大小，并且可以容纳更大的字体大小，而不会影响易用性。

要启用 200% 字号，请按以下步骤操作：

  1. 打开“设置”应用，然后依次前往无障碍 > 显示大小和文字。
  2. 在字号选项中，点按加号 (+) 图标，直到启用最大字号设置，如本部分随附的图片所示。

针对文本大小使用放大像素 (sp) 单位

请务必始终以 sp 为单位指定文本大小。当应用使用 sp 单位时，Android 可以应用用户的首选文本大小，并相应地进行缩放。

不要为内边距使用 sp 单位，也不要定义假设存在隐式内边距的视图高度：使用非线性字体放大 sp 尺寸可能并不成比例，因此 4sp + 20sp 可能并不等于 24sp。

转换放大像素 (sp) 单位

使用 TypedValue.applyDimension() 从 sp 单位转换为像素，并使用 TypedValue.deriveDimension() 将像素转换为 sp。这些方法会自动应用适当的非线性放大曲线。

避免使用 Configuration.fontScale 或 DisplayMetrics.scaledDensity 对等式进行硬编码。由于字体放大是非线性的，因此 scaledDensity 字段不再准确。fontScale 字段应仅用于提供信息，因为字体不再使用单个标量值进行缩放。

针对 lineHeight 使用 sp 单位

请始终使用 sp 单位（而非 dp）定义 android:lineHeight，以便行高随文本一起缩放。否则，如果您的文字是 sp，但 lineHeight 是 dp 或像素，则文字不会缩放，看起来会很拥挤。 TextView 会自动更正 lineHeight，以便保留您预期的比例，但前提是 textSize 和 lineHeight 均以 sp 单位定义。

摄像头和媒体

图片 Ultra HDR

An illustration of Standard Dynamic Range (SDR) versus High Dynamic Range (HDR) image quality.

Android 14 adds support for High Dynamic Range (HDR) images that retain more of the information from the sensor when taking a photo, which enables vibrant colors and greater contrast. Android uses the Ultra HDR format, which is fully backward compatible with JPEG images, allowing apps to seamlessly interoperate with HDR images, displaying them in Standard Dynamic Range (SDR) as needed.

Rendering these images in the UI in HDR is done automatically by the framework when your app opts in to using HDR UI for its Activity Window, either through a manifest entry or at runtime by calling Window.setColorMode(). You can also capture compressed Ultra HDR still images on supported devices. With more colors recovered from the sensor, editing in post can be more flexible. The Gainmap associated with Ultra HDR images can be used to render them using OpenGL or Vulkan.

相机扩展中的缩放、聚焦、postview 等功能

Android 14 upgrades and improves camera extensions, allowing apps to handle longer processing times, which enables improved images using compute-intensive algorithms like low-light photography on supported devices. These features give users an even more robust experience when using camera extension capabilities. Examples of these improvements include:

传感器内变焦

当 CameraCharacteristics 中的 REQUEST_AVAILABLE_CAPABILITIES_STREAM_USE_CASE 包含 SCALER_AVAILABLE_STREAM_USE_CASES_CROPPED_RAW 时，您的应用可以使用高级传感器功能，将剪裁后的 RAW 数据流的像素与全视野范围相同，方法是将 CaptureRequest 与将数据流用例设置为 CameraMetadata.SCALER_AVAILABLE_STREAM_USE_CASES_CROPPED_RAW 的 RAW 目标搭配使用。通过实现请求替换控件，更新后的相机可让用户在其他相机控件准备就绪之前使用缩放控件。

无损 USB 音频

Android 14 支持无损音频格式，可通过 USB 有线耳机提供发烧友级体验。您可以查询 USB 设备的首选混音器属性，注册监听器以监听首选混音器属性的更改，以及使用 AudioMixerAttributes 类配置混音器属性。此类表示音频混音器的格式，例如声道掩码、采样率和行为。该类允许直接发送音频，而无需混音、调节音量或处理效果。

开发者工作效率和工具

Credential Manager

Android 14 adds Credential Manager as a platform API, with additional support back to Android 4.4 (API level 19) devices through a Jetpack Library using Google Play services. Credential Manager aims to make sign-in easier for users with APIs that retrieve and store credentials with user-configured credential providers. Credential Manager supports multiple sign-in methods, including username and password, passkeys, and federated sign-in solutions (such as Sign-in with Google) in a single API.

Passkeys provide many advantages. For example, passkeys are built on industry standards, can work across different operating systems and browser ecosystems, and can be used with both websites and apps.

For more information, see the Credential Manager and passkeys documentation and the blogpost about Credential Manager and passkeys.

健康数据共享

Health Connect is an on-device repository for user health and fitness data. It allows users to share data between their favorite apps, with a single place to control what data they want to share with these apps.

On devices running Android versions prior to Android 14, Health Connect is available to download as an app on the Google Play store. Starting with Android 14, Health Connect is part of the platform and receives updates through Google Play system updates without requiring a separate download. With this, Health Connect can be updated frequently, and your apps can rely on Health Connect being available on devices running Android 14 or higher. Users can access Health Connect from the Settings in their device, with privacy controls integrated into the system settings.

Users can get started using Health Connect without a separate app download on devices running Android 14 or higher.
Users can control which apps have access to their health and fitness data through system settings.

Health Connect includes several new features in Android 14, such as exercise routes, allowing users to share a route of their workout which can be visualized on a map. A route is defined as a list of locations saved within a window of time, and your app can insert routes into exercise sessions, tying them together. To ensure that users have complete control over this sensitive data, users must allow sharing individual routes with other apps.

For more information, see the Health Connection documentation and the blogpost on What's new in Android Health.

OpenJDK 17 更新

Android 14 将继续更新 Android 的核心库，以与最新 OpenJDK LTS 版本中的功能保持一致，包括适合应用和平台开发者的库更新和 Java 17 语言支持。

其中包含以下功能和改进：

  • 将大约 300 个 java.base 类更新为支持 Java 17。
  • 文本块 - 为 Java 编程语言引入了多行字符串字面量。
  • instanceof 模式匹配：可让对象在 instanceof 中被视为具有特定类型，而无需任何额外的变量。
  • 密封类：允许您限制哪些类和接口可以扩展或实现它们。

得益于 Google Play 系统更新 (Project Mainline)，6 亿多台设备能够接收包含这些更改的最新 Android 运行时 (ART) 更新。我们致力于为应用提供更加一致、安全的跨设备环境，并为用户提供独立于平台版本的新功能。

Java 和 OpenJDK 是 Oracle 及/或其关联公司的商标或注册商标。

针对应用商店的改进

Android 14 introduces several PackageInstaller APIs that allow app stores to improve their user experience.

Request install approval before downloading

Installing or updating an app might require user approval. For example, when an installer making use of the REQUEST_INSTALL_PACKAGES permission attempts to install a new app. In prior Android versions, app stores can only request user approval after APKs are written to the install session and the session is committed.

Starting with Android 14, the requestUserPreapproval() method lets installers request user approval before committing the install session. This improvement lets an app store defer downloading any APKs until after the installation has been approved by the user. Furthermore, once a user has approved installation, the app store can download and install the app in the background without interrupting the user.

Claim responsibility for future updates

The setRequestUpdateOwnership() method allows an installer to indicate to the system that it intends to be responsible for future updates to an app it is installing. This capability enables update ownership enforcement, meaning that only the update owner is permitted to install automatic updates to the app. Update ownership enforcement helps to ensure that users receive updates only from the expected app store.

Any other installer, including those making use of the INSTALL_PACKAGES permission, must receive explicit user approval in order to install an update. If a user decides to proceed with an update from another source, update ownership is lost.

Update apps at less-disruptive times

App stores typically want to avoid updating an app that is actively in use because this leads to the app's running processes being killed, which potentially interrupts what the user was doing.

Starting with Android 14, the InstallConstraints API gives installers a way to ensure that their app updates happen at an opportune moment. For example, an app store can call the commitSessionAfterInstallConstraintsAreMet() method to make sure that an update is only committed when the user is no longer interacting with the app in question.

Seamlessly install optional splits

With split APKs, features of an app can be delivered in separate APK files, rather than as a monolithic APK. Split APKs allow app stores to optimize the delivery of different app components. For example, app stores might optimize based on the properties of the target device. The PackageInstaller API has supported splits since its introduction in API level 22.

In Android 14, the setDontKillApp() method allows an installer to indicate that the app's running processes shouldn't be killed when new splits are installed. App stores can use this feature to seamlessly install new features of an app while the user is using the app.

应用元数据软件包

从 Android 14 开始，Android 软件包安装程序可让您指定应用元数据（例如数据安全做法），以在 Google Play 等应用商店页面上架。

检测用户何时截取设备屏幕截图

为了打造更加标准化的屏幕截图检测体验，Android 14 引入了可保护隐私的屏幕截图检测 API。借助此 API，应用可以按 activity 注册回调。如果用户在该 activity 可见时截取屏幕截图，系统会调用这些回调并通知用户。

用户体验

Sharesheet 自定义操作和经过改进的排名系统

Android 14 updates the system sharesheet to support custom app actions and more informative preview results for users.

Add custom actions

With Android 14, your app can add custom actions to the system sharesheet it invokes.

Screenshot of custom actions on the sharesheet.

Improve ranking of Direct Share targets

Android 14 uses more signals from apps to determine the ranking of the direct share targets to provide more helpful results for the user. To provide the most useful signal for ranking, follow the guidance for improving rankings of your Direct Share targets. Communication apps can also report shortcut usage for outgoing and incoming messages.

Direct Share row in the sharesheet, as shown by 1

支持内置和自定义预测性返回动画

Video: Predictive back animations

Android 13 introduced the predictive back-to-home animation behind a developer option. When used in a supported app with the developer option enabled, swiping back shows an animation indicating that the back gesture exits the app back to the home screen.

Android 14 includes multiple improvements and new guidance for Predictive Back:

With this Android 14 preview release, all features of Predictive Back remain behind a developer option. See the developer guide to migrate your app to predictive back, as well as the developer guide to creating custom in-app transitions.

大屏设备制造商按应用替换项

Per-app overrides enable device manufacturers to change the behavior of apps on large screen devices. For example, the FORCE_RESIZE_APP override instructs the system to resize the app to fit display dimensions (avoiding size compatibility mode) even if resizeableActivity="false" is set in the app manifest.

Overrides are intended to improve the user experience on large screens.

New manifest properties enable you to disable some device manufacturer overrides for your app.

大屏设备用户按应用替换项

Per-app overrides change the behavior of apps on large screen devices. For example, the OVERRIDE_MIN_ASPECT_RATIO_LARGE device manufacturer override sets the app aspect ratio to 16:9 regardless of the app's configuration.

Android 14 QPR1 enables users to apply per‑app overrides by means of a new settings menu on large screen devices.

应用屏幕共享

App screen sharing enables users to share an app window instead of the entire device screen during screen content recording.

With app screen sharing, the status bar, navigation bar, notifications, and other system UI elements are excluded from the shared display. Only the content of the selected app is shared.

App screen sharing improves productivity and privacy by enabling users to run multiple apps but limit content sharing to a single app.

Pixel 8 Pro 上由 LLM 提供支持的 Gboard 智能回复功能

在搭载 12 月功能分块的 Pixel 8 Pro 设备上，开发者可以在 Gboard 中试用质量更高的智能回复，这些回复由在 Google Tensor 上运行的设备端大语言模型 (LLM) 提供支持。

此功能目前仅在 WhatsApp、Line 和 KakaoTalk 中以美式英语的形式提供给用户进行小范围测试。此功能需要使用 Pixel 8 Pro 设备，并将 Gboard 用作键盘。

如需试用此功能，请先依次前往设置 > 开发者选项 > AiCore 设置 > 启用 Aicore 持久性，启用该功能。

接下来，在受支持的应用中打开对话，即可在 Gboard 的建议栏中看到依托 LLM 的智能回复，以便回复收到的消息。

Gboard 利用设备端 LLM 提供更高质量的智能回复。

图形

路径可查询和插值

Android 的 Path API 是一种强大且灵活的机制，可用于创建和渲染矢量图形，能够描边或填充路径、根据线段或二次曲线或立方曲线构建路径、执行布尔运算以获取更复杂的形状，或同时执行所有这些操作。但有一个限制是，您无法了解 Path 对象中实际包含的内容；该对象的内部信息在创建后对调用方是不透明的。

如需创建 Path，您可以调用 moveTo()、lineTo() 和 cubicTo() 等方法来添加路径段。但是，无法询问该路径有哪些片段，因此您必须在创建时保留该信息。

从 Android 14 开始，您可以查询路径以了解其内部内容。首先，您需要使用 Path.getPathIterator API 获取 PathIterator 对象：

Kotlin

val path = Path().apply {
    moveTo(1.0f, 1.0f)
    lineTo(2.0f, 2.0f)
    close()
}
val pathIterator = path.pathIterator

Java

Path path = new Path();
path.moveTo(1.0F, 1.0F);
path.lineTo(2.0F, 2.0F);
path.close();
PathIterator pathIterator = path.getPathIterator();

接下来，您可以调用 PathIterator 逐个遍历片段，并检索每个片段的所有必要数据。以下示例使用了 PathIterator.Segment 对象，它会为您打包数据：

Kotlin

for (segment in pathIterator) {
    println("segment: ${segment.verb}, ${segment.points}")
}

Java

while (pathIterator.hasNext()) {
    PathIterator.Segment segment = pathIterator.next();
    Log.i(LOG_TAG, "segment: " + segment.getVerb() + ", " + segment.getPoints());
}

PathIterator 还有一个非分配版 next()，您可以在其中传入缓冲区来保存点数据。

查询 Path 数据的一个重要用例是插值。例如，您可能想在两个不同的路径之间添加动画（或变形）。为了进一步简化该用例，Android 14 针对 Path 还包含 interpolate() 方法。假设两个路径具有相同的内部结构，interpolate() 方法会使用该插值结果创建一个新的 Path。以下示例返回了一个形状介于 path 和 otherPath 之间的一半（线性插值为 0.5）的路径：

Kotlin

val interpolatedResult = Path()
if (path.isInterpolatable(otherPath)) {
    path.interpolate(otherPath, .5f, interpolatedResult)
}

Java

Path interpolatedResult = new Path();
if (path.isInterpolatable(otherPath)) {
    path.interpolate(otherPath, 0.5F, interpolatedResult);
}

Jetpack graphics-path 库也为早期版本的 Android 启用了类似的 API。

使用顶点着色器和片段着色器的自定义网格

Android has long supported drawing triangle meshes with custom shading, but the input mesh format has been limited to a few predefined attribute combinations. Android 14 adds support for custom meshes, which can be defined as triangles or triangle strips, and can, optionally, be indexed. These meshes are specified with custom attributes, vertex strides, varying, and vertex and fragment shaders written in AGSL.

The vertex shader defines the varyings, such as position and color, while the fragment shader can optionally define the color for the pixel, typically by using the varyings created by the vertex shader. If color is provided by the fragment shader, it is then blended with the current Paint color using the blend mode selected when drawing the mesh. Uniforms can be passed into the fragment and vertex shaders for additional flexibility.

Canvas 的硬件缓冲区渲染器

协助使用 Android 的 Canvas API 通过 硬件加速至 HardwareBuffer、Android 14 引入了 HardwareBufferRenderer。如果您的用例涉及通过 SurfaceControl 与系统合成器通信以实现低延迟绘制，此 API 特别有用。