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。

如需查看添加、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

各应用语言偏好设定

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

Regional preferences enable users to personalize temperature units, the first day of the week, and numbering systems. A European living in the United States might prefer temperature units to be in Celsius rather than Fahrenheit and for apps to treat Monday as the beginning of the week instead of the US default of Sunday.

New Android Settings menus for these preferences provide users with a discoverable and centralized location to change app preferences. These preferences also persist through backup and restore. Several APIs and intents—such as getTemperatureUnit and getFirstDayOfWeek— grant your app read access to user preferences, so your app can adjust how it displays information. You can also register a BroadcastReceiver on ACTION_LOCALE_CHANGED to handle locale configuration changes when regional preferences change.

To find these settings, open the Settings app and navigate to System > Languages & input > Regional preferences.

Regional preferences screen in Android system settings.
Temperature options for regional preferences in Android system settings.

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%，为弱视用户提供了符合网络内容无障碍指南 (WCAG) 的其他无障碍选项。

为防止屏幕上的大文本元素放大过大，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。非线性字体缩放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缩放的问题（例如文本被截断或文本因超大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。

如果您已经使用放大像素 (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。但是，您仍然应该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，并且可以适应更大的字体大小，而不影响易用性。

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缩放。

不要为内边距使用 sp 单位，也不假设隐式内边距定义视图高度：使用非线性字体缩放 sp 尺寸可能不成比例，因此 4sp + 20sp 可能不等于 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缩放曲线。

避免使用 Configuration.fontScale 或 DisplayMetrics.scaledDensity 对方程进行硬编码。由于字体缩放是非线性的，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。

对 lineHeight 使用 sp 单位

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，如果您的文本为 sp，而 lineHeight 以 dp 或 px 为单位，则文本无法缩放且看起来狭窄。TextView 会自动更正 lineHeight 以保留您预期的比例，但前提是以 sp 为单位同时定义 textSize 和 lineHeight。

摄像头和媒体

适用于图片的 Ultra HDR

标准动态范围 (SDR) 与高动态范围 (HDR) 图片质量的示意图。

Android 14 增加了对高动态范围 (HDR) 图片的支持，此类图片可在拍照时保留来自传感器的更多信息，从而实现鲜艳的色彩和更高的对比度。Android 采用 Ultra HDR 格式，这种格式可完全向后兼容 JPEG 图片，允许应用与 HDR 图片无缝互操作，从而根据需要以标准动态范围 (SDR) 显示图片。

当您的应用为其 Activity 窗口选择使用 HDR 界面（通过清单条目或在运行时通过调用 Window.setColorMode()）时，框架会自动在 HDR 界面中呈现这些图片。您还可以在支持的设备上拍摄压缩的 Ultra HDR 静态图片。从传感器中恢复的颜色越多，博文中的编辑效果就越灵活。与 Ultra HDR 图片关联的 Gainmap 可用于使用 OpenGL 或 Vulkan 渲染这些图片。

相机扩展中的缩放、对焦、预览等功能

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:

传感器内缩放

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，通过使用 CaptureRequest 以及数据流用例设置为 CameraMetadata.SCALER_AVAILABLE_STREAM_USE_CASES_CROPPED_RAW 的 RAW 目标，为剪裁后的 RAW 数据流提供与完整视野相同的像素。通过实现请求替换控件，更新后的摄像头让用户可在其他摄像头控件准备就绪之前实现缩放控制。

无损 USB 音频

Android 14 开始支持无损音频格式，通过 USB 有线耳机提供发烧级体验。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变化，并使用 AudioMixerAttributes 类配置混音器属性。此类表示格式，例如声道掩码、采样率和混音器行为。该类允许直接发送音频，而不进行混音、音量调整或处理效果。

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 是设备端用户健康与健身数据的存储区。它 让用户可以在喜爱的应用之间共享数据 控制他们要与这些应用分享哪些数据

在搭载 Android 14 之前版本的 Android 设备上，Health Connect 会 可在 Google Play 商店中以应用的形式下载。从 Android 14 开始，Health Connect 将成为 Android 平台的一部分，并通过 Google Play 系统更新接收更新，而无需单独下载。这样，健康 Connect 可能会经常更新，并且您的应用可以依赖于 Health Connect 在搭载 Android 14 或更高版本的设备上可用。用户可以访问“健康”应用 通过设备中的“设置”连接，以及集成到 与系统设置有关

用户无需单独的 在搭载 Android 14 或更高版本的设备上下载应用。
用户可以通过系统设置控制哪些应用可以访问其健康与健身数据。

Health Connect 包含 Android 14 中的多项新功能，例如锻炼 路线，让用户能够分享锻炼路线，并且路线直观 。路线定义为在一定时间范围内保存的位置列表，您的应用可以将路线插入锻炼时段，将它们关联起来。为确保用户可以完全控制这些敏感数据， 用户必须允许与其他应用分享具体路线。

有关详情，请参阅 Health Connection 文档以及关于 Android Health 的新变化。

OpenJDK 17 更新

Android 14 continues the work of refreshing Android's core libraries to align with the features in the latest OpenJDK LTS releases, including both library updates and Java 17 language support for app and platform developers.

The following features and improvements are included:

  • Updated approximately 300 java.base classes to Java 17 support.
  • Text Blocks, which introduce multi-line string literals to the Java programming language.
  • Pattern Matching for instanceof, which allows an object to be treated as having a specific type in an instanceof without any additional variables.
  • Sealed classes, which allow you restrict which classes and interfaces can extend or implement them.

Thanks to Google Play system updates (Project Mainline), over 600 million devices are enabled to receive the latest Android Runtime (ART) updates that include these changes. This is part of our commitment to give apps a more consistent, secure environment across devices, and to deliver new features and capabilities to users independent of platform releases.

Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.

针对应用商店的改进

Android 14 引入了多个 PackageInstaller API，可帮助应用商店改善其用户体验。

下载之前请求批准安装

安装或更新应用可能需要用户批准。 例如，当使用 REQUEST_INSTALL_PACKAGES 权限的安装程序尝试安装新应用时。在之前的 Android 版本中，应用商店只有在 APK 写入安装会话且该会话已提交之后才能请求用户批准。

从 Android 14 开始，requestUserPreapproval() 方法可让安装程序在提交安装会话之前请求用户批准。此项改进可让应用商店将任何 APK 的下载操作推迟到用户批准安装之后。此外，用户批准安装后，应用商店可以在后台下载并安装应用，而不会干扰用户。

承担未来更新的责任

通过 setRequestUpdateOwnership() 方法，安装程序可以告知系统它打算负责未来安装的应用更新。此功能可实现更新所有权强制执行，即只有更新所有者才能为应用安装自动更新。更新所有权强制执行有助于确保用户仅从预期的应用商店接收更新。

任何其他安装程序（包括使用 INSTALL_PACKAGES 权限的安装程序）都必须获得用户的明确批准，才能安装更新。如果用户决定继续从其他来源进行更新，更新所有权将会丢失。

在干扰较少的时段更新应用

应用商店通常希望避免更新正在使用的应用，因为这会导致应用正在运行的进程被终止，而这可能会中断用户正在执行的操作。

从 Android 14 开始，InstallConstraints API 让安装程序可以确保其应用更新在适当的时机进行。例如，应用商店可以调用 commitSessionAfterInstallConstraintsAreMet() 方法来确保仅在用户不再与相关应用互动时进行更新。

无缝安装可选拆分

借助拆分 APK，应用的功能可以通过单独的 APK 文件提供，而不是以单体式 APK 的形式提供。借助拆分 APK，应用商店可以优化不同应用组件的提供。例如，应用商店可能会根据目标设备的属性进行优化。自从在 API 级别 22 中引入以来，PackageInstaller API 一直支持拆分。

在 Android 14 中，setDontKillApp() 方法可让安装程序指明在安装新的分块时不应终止应用正在运行的进程。应用商店可以使用此功能，在用户使用应用时无缝安装应用的新功能。

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），以将其添加到 Google Play 等应用商店页面。

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

借助按应用替换项，设备制造商可以更改应用在大屏设备上的行为。例如，FORCE_RESIZE_APP 替换项会指示系统调整应用大小以适应显示屏尺寸（避免进入尺寸兼容模式），即使在应用清单中设置了 resizeableActivity="false" 也是如此。

替换项旨在改善大屏设备上的用户体验。

借助新的清单属性，您可以为应用停用某些设备制造商替换项。

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.

分享应用界面

应用屏幕共享功能让用户能够在录制屏幕内容期间共享应用窗口，而非整个设备屏幕。

使用应用屏幕共享时，状态栏、导航栏、通知和其他系统界面元素会从共享显示屏中排除。系统只会分享所选应用的内容。

应用屏幕共享可让用户运行多个应用，但仅限单个应用共享内容，从而提高效率和隐私性。

Pixel 8 Pro 上 Gboard 中依托 LLM 的智能回复功能

On Pixel 8 Pro devices with the December Feature Drop, developers can try out higher-quality smart replies in Gboard powered by on-device Large Language Models (LLMs) running on Google Tensor.

This feature is available as a limited preview for US English in WhatsApp, Line, and KakaoTalk. It requires using a Pixel 8 Pro device with Gboard as your keyboard.

To try it out, first enable the feature in Settings > Developer Options > AiCore Settings > Enable Aicore Persistent.

Next, open a conversation in a supported app to see LLM-powered Smart Reply in Gboard's suggestion strip in response to incoming messages.

Gboard utilizes on-device LLMs to provide higher-quality smart replies.

图形

路径可查询和插值

Android's Path API is a powerful and flexible mechanism for creating and rendering vector graphics, with the ability to stroke or fill a path, construct a path from line segments or quadratic or cubic curves, perform boolean operations to get even more complex shapes, or all of these simultaneously. One limitation is the ability to find out what is actually in a Path object; the internals of the object are opaque to callers after creation.

To create a Path, you call methods such as moveTo(), lineTo(), and cubicTo() to add path segments. But there has been no way to ask that path what the segments are, so you must retain that information at creation time.

Starting in Android 14, you can query paths to find out what's inside of them. First, you need to get a PathIterator object using the Path.getPathIterator API:

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();

Next, you can call PathIterator to iterate through the segments one by one, retrieving all of the necessary data for each segment. This example uses PathIterator.Segment objects, which packages up the data for you:

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 also has a non-allocating version of next() where you can pass in a buffer to hold the point data.

One of the important use cases of querying Path data is interpolation. For example, you might want to animate (or morph) between two different paths. To further simplify that use case, Android 14 also includes the interpolate() method on Path. Assuming the two paths have the same internal structure, the interpolate() method creates a new Path with that interpolated result. This example returns a path whose shape is halfway (a linear interpolation of .5) between path and otherPath:

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);
}

The Jetpack graphics-path library enables similar APIs for earlier versions of Android as well.

具有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.

适用于画布的硬件缓冲区渲染程序

To assist in using Android's Canvas API to draw with hardware acceleration into a HardwareBuffer, Android 14 introduces HardwareBufferRenderer. This API is particularly useful when your use case involves communication with the system compositor through SurfaceControl for low-latency drawing.