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%

Starting in Android 14, the system supports font scaling up to 200%, providing low-vision users with additional accessibility options that align with Web Content Accessibility Guidelines (WCAG).

To prevent large text elements on screen from scaling too large, the system applies a nonlinear scaling curve. This scaling strategy means that large text doesn't scale at the same rate as smaller text. Nonlinear font scaling helps preserve the proportional hierarchy between elements of different sizes while mitigating issues with linear text scaling at high degrees (such as text being cut off or text that becomes harder to read due to an extremely large display sizes).

Test your app with nonlinear font scaling

Enable the maximum font size in a device's accessibility settings to test your app.

If you already use scaled pixels (sp) units to define text sizing, then these additional options and scaling improvements are applied automatically to the text in your app. However, you should still perform UI testing with the maximum font size enabled (200%) to ensure that your app applies the font sizes correctly and can accommodate larger font sizes without impacting usability.

To enable 200% font size, follow these steps:

1. Open the Settings app and navigate to Accessibility > Display size and text.
2. For the Font size option, tap the plus (+) icon until the maximum font size setting is enabled, as shown in the image that accompanies this section.

Use scaled pixel (sp) units for text-sizes

Remember to always specify text sizes in sp units. When your app uses sp units, Android can apply the user's preferred text size and scale it appropriately.

Don't use sp units for padding or define view heights assuming implicit padding: with nonlinear font scaling sp dimensions might not be proportional, so 4sp + 20sp might not equal 24sp.

Convert scaled pixel (sp) units

Use TypedValue.applyDimension() to convert from sp units to pixels, and use TypedValue.deriveDimension() to convert pixels to sp. These methods apply the appropriate nonlinear scaling curve automatically.

Avoid hardcoding equations using Configuration.fontScale or DisplayMetrics.scaledDensity. Because font scaling is nonlinear, the scaledDensity field is no longer accurate. The fontScale field should be used for informational purposes only because fonts are no longer scaled with a single scalar value.

Use sp units for lineHeight

Always define android:lineHeight using sp units instead of dp, so the line height scales along with your text. Otherwise, if your text is sp but your lineHeight is in dp or px, it doesn't scale and looks cramped. TextView automatically corrects the lineHeight so that your intended proportions are preserved, but only if both textSize and lineHeight are defined in sp units.

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:

• Dynamic still capture processing latency estimation provides much more accurate still capture latency estimates based on the current scene and environment conditions. Call CameraExtensionSession.getRealtimeStillCaptureLatency() to get a StillCaptureLatency object that has two latency estimation methods. The getCaptureLatency() method returns the estimated latency between onCaptureStarted and onCaptureProcessStarted(), and the getProcessingLatency() method returns the estimated latency between onCaptureProcessStarted() and the final processed frame being available.
• Support for capture progress callbacks so that apps can display the current progress of long-running, still-capture processing operations. You can check if this feature is available with CameraExtensionCharacteristics.isCaptureProcessProgressAvailable, and if it is, you implement the onCaptureProcessProgressed() callback, which has the progress (from 0 to 100) passed in as a parameter.

• Extension specific metadata, such as CaptureRequest.EXTENSION_STRENGTH for dialing in the amount of an extension effect, such as the amount of background blur with EXTENSION_BOKEH.

• Postview Feature for Still Capture in camera extensions, which provides a less-processed image more quickly than the final image. If an extension has increased processing latency, a postview image could be provided as a placeholder to improve UX and switched out later for the final image. You can check if this feature is available with CameraExtensionCharacteristics.isPostviewAvailable. Then you can pass an OutputConfiguration to ExtensionSessionConfiguration.setPostviewOutputConfiguration.

• Support for SurfaceView allowing for a more optimized and power-efficient preview render path.

• Support for tap to focus and zoom during extension usage.

传感器内缩放

When REQUEST_AVAILABLE_CAPABILITIES_STREAM_USE_CASE in CameraCharacteristics contains SCALER_AVAILABLE_STREAM_USE_CASES_CROPPED_RAW, your app can use advanced sensor capabilities to give a cropped RAW stream the same pixels as the full field of view by using a CaptureRequest with a RAW target that has stream use case set to CameraMetadata.SCALER_AVAILABLE_STREAM_USE_CASES_CROPPED_RAW. By implementing the request override controls, the updated camera gives users zoom control even before other camera controls are ready.

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

注意 ：如果您开发了第三方应用商店，我们非常希望听取您的反馈，因此不妨试用这些 API，并将您的想法告诉我们！

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。

注意 ：如果您在 Google Play 上分发应用，请考虑使用 Play Feature Delivery，以便允许应用的某些功能按条件分发或按需下载。

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。

注意：该回调未提供实际屏幕截图的图片。用户截取屏幕截图后，屏幕上的内容将由您的应用决定。

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:

• You can set android:enableOnBackInvokedCallback=true to opt in to predictive back system animations per-Activity instead of for the entire app.
• We've added new system animations to accompany the back-to-home animation from Android 13. The new system animations are cross-activity and cross-task, which you get automatically after migrating to Predictive Back.
• We've added new Material Component animations for Bottom sheets, Side sheets, and Search.
• We've created design guidance for creating custom in-app animations and transitions.
• We've added new APIs to support custom in-app transition animations:
  • handleOnBackStarted, handleOnBackProgressed, handleOnBackCancelled in OnBackPressedCallback
  • onBackStarted, onBackProgressed, onBackCancelled in OnBackAnimationCallback
  • Use overrideActivityTransition instead of overridePendingTransition for transitions that respond as the user swipes 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

注意 ：此功能适用于搭载 Android 14 QPR1 或更高版本的设备。

按应用替换会更改大屏设备上应用的行为。例如，无论应用的配置如何，OVERRIDE_MIN_ASPECT_RATIO_LARGE 设备制造商替换项都会将应用宽高比设置为 16:9。

Android 14 QPR1 允许用户在大屏设备上通过新的设置菜单应用按应用替换项。

分享应用界面

注意 ：此功能适用于搭载 Android 14 QPR2 或更高版本的设备。

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

在附带 12 月功能更新版的 Pixel 8 Pro 设备上，开发者可以在 Gboard 中体验更优质的智能回复，该功能由在 Google Tensor 上运行的设备端大型语言模型 (LLM) 提供支持。

此功能目前仅在 WhatsApp、Line 和 KakaoTalk 中推出美式英语的有限预览版。该功能需要使用一部支持 Gboard 的 Pixel 8 Pro 设备作为键盘。

如需试用，请先依次选择设置 > 开发者选项 > AiCore 设置 > 启用 Aicore Persistent 以启用该功能。

接下来，在受支持的应用中打开对话，以在 Gboard 的建议栏中看到由 LLM 提供支持的智能回复，以便响应收到的消息。

Gboard 利用设备端 LLM 提供更优质的智能回复。

注意 ：此功能预览版将在 12 月功能更新后开始面向设备推出。如果您还没有看到新的智能回复行为，请等待几天，然后重试。下载模型可能也需要一些时间，所以夜间通过 Wi-Fi 给设备充电有助于加快速度。

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 长期支持绘制具有自定义着色的三角形网格，但输入网格格式被限制为几种预定义的属性组合。Android 14 增加了对自定义网格的支持，自定义网格可定义为三角形或三角形带，并且可以视需要编入索引。这些网格通过自定义属性、顶点步长、转换以及用 AGSL 编写的顶点和片段着色器指定。

顶点着色器定义变化，例如位置和颜色，而 fragment 着色器可以选择定义像素的颜色，通常通过使用顶点着色器创建的变化。如果 fragment 着色器提供了颜色，则它会使用绘制网格时选择的混合模式与当前的 Paint 颜色混合。您可以将 uniform 传递到 fragment 和顶点着色器中，以提高灵活性。

适用于画布的硬件缓冲区渲染程序

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。