功能和 API

Android 16 面向开发者引入了一些出色的新功能和 API。以下各部分总结了这些功能，可帮助您开始使用相关 API。

有关新增、修改和移除的 API 的详细列表，请参阅 API 差异报告。如需详细了解新的 API，请访问 Android API 参考文档，新 API 会突出显示以方便查看。

您还应查看平台变更可能会在哪些方面影响您的应用。如需了解详情，请参阅以下页面：

核心功能

Android 包含一些新的 API，可扩展 Android 系统的核心功能。

2025 年发布了两个 Android API

  • 此预览版适用于 Android 的下一个主要版本，计划于 2025 年第 2 季度发布。此版本与我们过去的所有 API 版本类似，我们可以进行计划性的行为更改，这些更改通常与 targetSdkVersion 相关联。
  • 我们计划提前一个季度（2021 年第 2 季度，而非之前的第 3 季度）发布主要版本，以便更好地与整个生态系统中的设备发布时间表保持一致，让更多设备能够更早地搭载 Android 主要版本。由于主要版本将于第 2 季度发布，因此您需要比往年提前几个月进行年度兼容性测试，以确保您的应用已做好准备。
  • 我们计划在 2025 年第 4 季度再发布一次，届时还将推出新的开发者 API。2025 年只有第二季度的主要版本包含可能影响应用的计划行为变更。

除了新的开发者 API 之外，第 4 季度次要版本还将包含功能更新、优化和 bug 修复；其中不会包含任何会影响应用的行为变更。

2025 年 Android 版本的时间轴视图，请注意，25Q2 版本是一个主要版本，25Q4 版本是一个次要版本。

我们将继续每季度发布 Android 版本。在 API 版本之间，第 1 季度和第 3 季度的更新将提供增量更新，以帮助确保持续提供高质量的服务。我们正积极与设备合作伙伴合作，将 Q2 版本推广到尽可能多的设备。

在主要版本和次要版本中使用新 API

目前，使用 SDK_INT 常量与 VERSION_CODES 结合使用，即可通过检查 API 级别来保护代码块。我们将继续支持主要 Android 版本。

if (SDK_INT >= VERSION_CODES.BAKLAVA) {
  // Use APIs introduced in Android 16
}

新的 SDK_INT_FULL 常量可用于针对主要版本和次要版本进行 API 检查，并使用新的 VERSION_CODES_FULL 枚举。

if (SDK_INT_FULL >= VERSION_CODES_FULL.[MAJOR or MINOR RELEASE]) {
  // Use APIs introduced in a major or minor release
}

您还可以使用 Build.getMinorSdkVersion() 方法仅获取 SDK 次要版本。

val minorSdkVersion = Build.getMinorSdkVersion(VERSION_CODES_FULL.BAKLAVA)

这些 API 尚未最终确定，可能会发生变化，因此如果您有任何疑虑，请向我们发送反馈。

用户体验和系统界面

Android 16 为应用开发者和用户提供了更多控制权和灵活性，以便他们根据自己的需求配置设备。

以进度为中心的通知

Android 16 引入了以进度为中心的通知，可帮助用户顺畅地跟踪用户发起的端到端历程。

Notification.ProgressStyle 是一种新的通知样式，可让您创建以进度为中心的通知。主要用例包括共享车辆、送货和导航。在 Notification.ProgressStyle 类中，您可以使用点和细分来表示用户体验历程中的状态和里程碑。

如需了解详情，请参阅以进度为中心的通知文档页面。

锁屏上显示的以进度为中心的通知。
在通知栏中显示的以进度为中心的通知。

预测性返回更新

Android 16 添加了新 API，可帮助您在手势导航中启用预测性返回系统动画，例如“返回主屏幕”动画。通过使用新的 PRIORITY_SYSTEM_NAVIGATION_OBSERVER 注册 onBackInvokedCallback，您的应用可以在系统处理返回导航时接收常规的 onBackInvoked 调用，而不会影响正常的返回导航流程。

Android 16 还添加了 finishAndRemoveTaskCallback() 和 moveTaskToBackCallback。通过向 OnBackInvokedDispatcher 注册这些回调，系统可以在调用返回手势时触发特定行为并播放相应的提前动画。

更丰富的触感反馈

自诞生之日起，Android 就提供了对触感反馈致动器的控制。

Android 11 添加了对更复杂的触感反馈效果的支持，更高级的致动器可以通过设备定义的语义基元 VibrationEffect.Compositions 支持这些效果。

Android 16 添加了触感反馈 API，让应用能够定义触感反馈效果的振幅和频率曲线，同时抽象出设备功能之间的差异。

开发者工作效率和工具

虽然我们的大部分工作都是围绕 Android Studio、Jetpack Compose 和 Android Jetpack 库等工具来提高您的工作效率，但我们始终在寻找平台中可帮助您实现愿景的方法。

动态壁纸的内容处理

In Android 16, the live wallpaper framework is gaining a new content API to address the challenges of dynamic, user-driven wallpapers. Currently, live wallpapers incorporating user-provided content require complex, service-specific implementations. Android 16 introduces WallpaperDescription and WallpaperInstance. WallpaperDescription lets you identify distinct instances of a live wallpaper from the same service. For example, a wallpaper that has instances on both the home screen and on the lock screen may have unique content in both places. The wallpaper picker and WallpaperManager use this metadata to better present wallpapers to users, streamlining the process for you to create diverse and personalized live wallpaper experiences.

性能和电池

Android 16 引入了可帮助您收集应用相关数据分析的 API。

系统触发的性能分析

ProfilingManager was added in Android 15, giving apps the ability to request profiling data collection using Perfetto on public devices in the field. However, since this profiling must be started from the app, critical flows such as startups or ANRs would be difficult or impossible for apps to capture.

To help with this, Android 16 introduces system-triggered profiling to ProfilingManager. Apps can register interest in receiving traces for certain triggers such as cold start reportFullyDrawn or ANRs, and then the system starts and stops a trace on the app's behalf. After the trace completes, the results are delivered to the app's data directory.

ApplicationStartInfo 中的启动组件

ApplicationStartInfo 在 Android 15 中添加，可让应用查看进程启动原因、启动类型、启动时间、节流和其他实用诊断数据。Android 16 添加了 getStartComponent()，用于区分触发启动的组件类型，这有助于优化应用的启动流程。

更好地进行作业内省

JobScheduler#getPendingJobReason() API 会返回作业可能处于待处理状态的原因。不过，作业处于待处理状态的原因可能有多种。

在 Android 16 中，我们引入了一个新 API JobScheduler#getPendingJobReasons(int jobId)，该 API 会返回作业处于待处理状态的多种原因，包括开发者设置的显式约束条件和系统设置的隐式约束条件。

我们还引入了 JobScheduler#getPendingJobReasonsHistory(int jobId)，用于返回最新约束条件更改的列表。

我们建议您使用该 API 来调试作业可能无法执行的原因，尤其是在您发现某些任务的成功率降低或某些作业完成延迟存在 bug 时。例如，未能在后台更新微件，或在应用启动之前未能调用预加载作业。

这还有助于您更好地了解某些作业是否因系统定义的约束条件而无法完成，而不是因明确设置的约束条件而无法完成。

自动调节刷新率

Adaptive refresh rate (ARR), introduced in Android 15, enables the display refresh rate on supported hardware to adapt to the content frame rate using discrete VSync steps. This reduces power consumption while eliminating the need for potentially jank-inducing mode-switching.

Android 16 introduces hasArrSupport() and getSuggestedFrameRate(int) while restoring getSupportedRefreshRates() to make it easier for your apps to take advantage of ARR. RecyclerView 1.4 internally supports ARR when it is settling from a fling or smooth scroll, and we're continuing our work to add ARR support into more Jetpack libraries. This frame rate article covers many of the APIs you can use to set the frame rate so that your app can directly use ARR.

ADPF 中的裕度 API

The SystemHealthManager introduces the getCpuHeadroom and getGpuHeadroom APIs, designed to provide games and resource-intensive apps with estimates of available CPU and GPU resources. These methods offer a way for you to gauge how your app or game can best improve system health, particularly when used in conjunction with other Android Dynamic Performance Framework (ADPF) APIs that detect thermal throttling.

By using CpuHeadroomParams and GpuHeadroomParams on supported devices, you can customize the time window used to compute the headroom and select between average or minimum resource availability. This can help you reduce your CPU or GPU resource usage accordingly, leading to better user experiences and improved battery life.

无障碍

Android 16 新增了无障碍功能 API 和功能，可帮助您让所有用户都能使用您的应用。

改进了无障碍功能 API

Android 16 adds additional APIs to enhance UI semantics that help improve consistency for users that rely on accessibility services, such as TalkBack.

Outline text for maximum text contrast

Users with low vision often have reduced contrast sensitivity, making it challenging to distinguish objects from their backgrounds. To help these users, Android 16 introduces outline text, replacing high contrast text, which draws a larger contrasting area around text to greatly improve legibility.

Android 16 contains new AccessibilityManager APIs to let your apps check or register a listener to see if this mode is enabled. This is primarily for UI Toolkits like Compose to offer a similar visual experience. If you maintain a UI Toolkit library or your app performs custom text rendering that bypasses the android.text.Layout class then you can use this to know when outline text is enabled.

Text with enhanced contrast before and after Android 16's new outline text accessibility feature

Duration added to TtsSpan

Android 16 extends TtsSpan with a TYPE_DURATION, consisting of ARG_HOURS, ARG_MINUTES, and ARG_SECONDS. This lets you directly annotate time duration, ensuring accurate and consistent text-to-speech output with services like TalkBack.

Support elements with multiple labels

Android currently allows UI elements to derive their accessibility label from another, and now offers the ability for multiple labels to be associated, a common scenario in web content. By introducing a list-based API within AccessibilityNodeInfo, Android can directly support these multi-label relationships. As part of this change, we've deprecated AccessibilityNodeInfo#setLabeledBy and #getLabeledBy in favor of #addLabeledBy, #removeLabeledBy, and #getLabeledByList.

Improved support for expandable elements

Android 16 adds accessibility APIs that allow you to convey the expanded or collapsed state of interactive elements, such as menus and expandable lists. By setting the expanded state using setExpandedState and dispatching TYPE_WINDOW_CONTENT_CHANGED AccessibilityEvents with a CONTENT_CHANGE_TYPE_EXPANDED content change type, you can ensure that screen readers like TalkBack announce state changes, providing a more intuitive and inclusive user experience.

Indeterminate ProgressBars

Android 16 adds RANGE_TYPE_INDETERMINATE, giving a way for you to expose RangeInfo for both determinate and indeterminate ProgressBar widgets, allowing services like TalkBack to more consistently provide feedback for progress indicators.

Tri-state CheckBox

The new AccessibilityNodeInfo getChecked and setChecked(int) methods in Android 16 now support a "partially checked" state in addition to "checked" and "unchecked." This replaces the deprecated boolean isChecked and setChecked(boolean).

Supplemental descriptions

When an accessibility service describes a ViewGroup, it combines content labels from its child views. If you provide a contentDescription for the ViewGroup, accessibility services assume you are also overriding the description of non-focusable child views. This can be problematic if you want to label things like a drop-down (for example, "Font Family") while preserving the current selection for accessibility (for example, "Roboto"). Android 16 adds setSupplementalDescription so you can provide text that provides information about a ViewGroup without overriding information from its children.

Required form fields

Android 16 adds setFieldRequired to AccessibilityNodeInfo so apps can tell an accessibility service that input to a form field is required. This is an important scenario for users filling out many types of forms, even things as simple as a required terms and conditions checkbox, helping users to consistently identify and quickly navigate between required fields.

将手机作为 LEA 助听器的麦克风输入设备，用于语音通话

Android 16 新增了一项功能，让 LE Audio 助听器用户能够在助听器的内置麦克风和手机上的麦克风之间切换，以进行语音通话。在嘈杂的环境或助听器麦克风可能无法正常工作的其他情况下，这会很有帮助。

LEA 助听器的环境音量控制

Android 16 adds the capability for users of LE Audio hearing aids to adjust the volume of ambient sound that is picked up by the hearing aid's microphones. This can be helpful in situations where background noise is too loud or too quiet.

相机

Android 16 增强了对专业相机用户的支持，允许进行混合自动曝光以及精确的色温和色调调整。新的夜间模式指示器可帮助应用了解何时切换到夜间模式相机会议以及何时从夜间模式相机会议切换回来。新的 Intent 操作可让您更轻松地拍摄动态照片，并且我们还在不断改进 UltraHDR 图片，支持 HEIC 编码和 ISO 21496-1 草稿标准中的新参数。

混合自动曝光

Android 16 向 Camera2 添加了新的混合自动曝光模式，让您可以手动控制曝光的特定方面，同时让自动曝光 (AE) 算法处理其余部分。您可以控制 ISO + AE 和曝光时间 + AE，与当前方法（您要么完全手动控制，要么完全依赖自动曝光）相比，可提供更大的灵活性。

fun setISOPriority() {
    // ... (Your existing code before the snippet) ...

    val availablePriorityModes = mStaticInfo.characteristics.get(
        CameraCharacteristics.CONTROL_AE_AVAILABLE_PRIORITY_MODES
    )

    // ... (Your existing code between the snippets) ...

    // Turn on AE mode to set priority mode
    reqBuilder.set(
        CaptureRequest.CONTROL_AE_MODE,
        CameraMetadata.CONTROL_AE_MODE_ON
    )
    reqBuilder.set(
        CaptureRequest.CONTROL_AE_PRIORITY_MODE,
        CameraMetadata.CONTROL_AE_PRIORITY_MODE_SENSOR_SENSITIVITY_PRIORITY
    )
    reqBuilder.set(
        CaptureRequest.SENSOR_SENSITIVITY,
        TEST_SENSITIVITY_VALUE
    )
    val request: CaptureRequest = reqBuilder.build()

    // ... (Your existing code after the snippet) ...
}

精确的色温和色调调整

Android 16 增加了对相机的精细色温和色调调整的支持，以更好地支持专业视频录制应用。在较低版本的 Android 中，您可以通过 CONTROL_AWB_MODE 控制白平衡设置，其中包含仅限于预设列表的选项，例如白炽灯、多云和黄昏。COLOR_CORRECTION_MODE_CCT 可让您使用 COLOR_CORRECTION_COLOR_TEMPERATURE 和 COLOR_CORRECTION_COLOR_TINT 根据相关色温精确调整白平衡。

fun setCCT() {
    // ... (Your existing code before this point) ...

    val colorTemperatureRange: Range<Int> =
        mStaticInfo.characteristics[CameraCharacteristics.COLOR_CORRECTION_COLOR_TEMPERATURE_RANGE]

    // Set to manual mode to enable CCT mode
    reqBuilder[CaptureRequest.CONTROL_AWB_MODE] = CameraMetadata.CONTROL_AWB_MODE_OFF
    reqBuilder[CaptureRequest.COLOR_CORRECTION_MODE] = CameraMetadata.COLOR_CORRECTION_MODE_CCT
    reqBuilder[CaptureRequest.COLOR_CORRECTION_COLOR_TEMPERATURE] = 5000
    reqBuilder[CaptureRequest.COLOR_CORRECTION_COLOR_TINT] = 30

    val request: CaptureRequest = reqBuilder.build()

    // ... (Your existing code after this point) ...
}

以下示例展示了应用不同色温和色调调整后的照片效果：

未应用色温或色调调整的原始图片。
将色温调整为 3000 的图片。
将色温调整为 7000 的图片。


将色调级别降低 50 的图片。
色调级别提高了 50 的图片。

相机夜间模式场景检测

为了帮助应用了解何时切换到夜间模式相机会话以及何时从夜间模式相机会话切换出，Android 16 添加了 EXTENSION_NIGHT_MODE_INDICATOR。如果受支持，则可在 Camera2 内的 CaptureResult 中使用。

这是我们在Instagram 如何让用户拍出令人惊艳的低光照片博文中提到的即将推出的 API。该博文提供了有关如何实现夜间模式的实用指南，并附有一份案例研究，该案例研究将应用内夜间模式照片质量的提升与通过应用内相机分享的照片数量的增加联系起来。

动态照片拍摄 intent 操作

Android 16 添加了标准 intent 操作 ACTION_MOTION_PHOTO_CAPTURE 和 ACTION_MOTION_PHOTO_CAPTURE_SECURE，用于请求相机应用拍摄动态照片并将其返回。

您必须传递额外的 EXTRA_OUTPUT 来控制将图片写入的位置，或者通过 Intent.setClipData(ClipData) 传递 Uri。如果您未设置 ClipData，系统会在调用 Context.startActivity(Intent) 时将其复制到该位置。

动态照片示例，显示静态图片和动态播放画面。

UltraHDR 图片增强功能

标准动态范围 (SDR) 与高动态范围 (HDR) 图片质量对比示意图。

Android 16 继续致力于通过 UltraHDR 图片提供出色的图片质量。它添加了对 HEIC 文件格式的 UltraHDR 图片的支持。这些图片将获得 ImageFormat 类型 HEIC_ULTRAHDR，并包含类似于现有 UltraHDR JPEG 格式的嵌入式增益图。我们还在努力为 UltraHDR 添加 AVIF 支持，敬请期待。

此外，Android 16 在 UltraHDR 中实现了 ISO 21496-1 草稿标准中的其他参数，包括能够获取和设置应应用增益图算法的色彩空间，以及支持使用 SDR 增益图的 HDR 编码基础图片。

图形

Android 16 包含最新的图形改进，例如使用 AGSL 实现自定义图形效果。

使用 AGSL 实现自定义图形效果

Android 16 添加了 RuntimeColorFilter 和 RuntimeXfermode，让您可以创作阈值、Sepia 和 Hue Saturation 等复杂效果，并将其应用于绘制调用。从 Android 13 开始，您可以使用 AGSL 创建扩展 Shader 的自定义 RuntimeShader。新 API 反映了这一点，添加了由 AGSL 驱动的 RuntimeColorFilter（用于扩展 ColorFilter）和 Xfermode 效果，让您可以在源像素和目标像素之间实现基于 AGSL 的自定义合成和混合。

private val thresholdEffectString = """
    uniform half threshold;

    half4 main(half4 c) {
        half luminosity = dot(c.rgb, half3(0.2126, 0.7152, 0.0722));
        half bw = step(threshold, luminosity);
        return bw.xxx1 * c.a;
    }"""

fun setCustomColorFilter(paint: Paint) {
   val filter = RuntimeColorFilter(thresholdEffectString)
   filter.setFloatUniform(0.5);
   paint.colorFilter = filter
}

连接

Android 16 更新了平台，让您的应用能够使用通信和无线技术方面的最新进展。

测距功能（增强型安全）

Android 16 adds support for robust security features in Wi-Fi location on supported devices with Wi-Fi 6's 802.11az, allowing apps to combine the higher accuracy, greater scalability, and dynamic scheduling of the protocol with security enhancements including AES-256-based encryption and protection against MITM attacks. This allows it to be used more safely in proximity use cases, such as unlocking a laptop or a vehicle door. 802.11az is integrated with the Wi-Fi 6 standard, leveraging its infrastructure and capabilities for wider adoption and easier deployment.

通用测距 API

Android 16 包含新的 RangingManager，它提供了在受支持的硬件上确定本地设备与远程设备之间的距离和角度的方法。RangingManager 支持使用各种测距技术，例如 BLE 信道声音探测、基于 BLE RSSI 的测距、超宽带和 Wi-Fi 往返时间。

配套设备管理器设备存在情况

Android 16 中引入了用于绑定配套应用服务的新 API。当 BLE 在范围内且蓝牙处于连接状态时，系统会绑定服务；当 BLE 不在范围内或蓝牙处于断开连接状态时，系统会解除绑定服务。应用将根据各种 DevicePresenceEvent 收到新的 'onDevicePresenceEvent()' 回调。如需了解详情，请参阅 'startObservingDevicePresence(ObservingDevicePresenceRequest)'。

媒体

Android 16 包含各种可提升媒体体验的功能。

改进了照片选择器

The photo picker provides a safe, built-in way for users to grant your app access to selected images and videos from both local and cloud storage, instead of their entire media library. Using a combination of Modular System Components through Google System Updates and Google Play services, it's supported back to Android 4.4 (API level 19). Integration requires just a few lines of code with the associated Android Jetpack library.

Android 16 includes the following improvements to the photo picker:

  • Embedded photo picker: New APIs that enable apps to embed the photo picker into their view hierarchy. This allows it to feel like a more integrated part of the app while still leveraging the process isolation that allows users to select media without the app needing overly broad permissions. To maximize compatibility across platform versions and simplify your integration, you'll want to use the forthcoming Android Jetpack library if you want to integrate the embedded photo picker.
  • Cloud search in photo picker: New APIs that enable searching from the cloud media provider for the Android photo picker. Search functionality in the photo picker is coming soon.

高级专业视频

Android 16 introduces support for the Advanced Professional Video (APV) codec which is designed to be used for professional level high quality video recording and post production.

The APV codec standard has the following features:

  • Perceptually lossless video quality (close to raw video quality)
  • Low complexity and high throughput intra-frame-only coding (without pixel domain prediction) to better support editing workflows
  • Support for high bit-rate range up to a few Gbps for 2K, 4K and 8K resolution content, enabled by a lightweight entropy coding scheme
  • Frame tiling for immersive content and for enabling parallel encoding and decoding
  • Support for various chroma sampling formats and bit-depths
  • Support for multiple decoding and re-encoding without severe visual quality degradation
  • Support multi-view video and auxiliary video like depth, alpha, and preview
  • Support for HDR10/10+ and user-defined metadata

A reference implementation of APV is provided through the OpenAPV project. Android 16 will implement support for the APV 422-10 Profile that provides YUV 422 color sampling along with 10-bit encoding and for target bitrates of up to 2Gbps.

隐私权

Android 16 包含多种有助于应用开发者保护用户隐私的功能。

健康数据共享更新

Health Connect 添加了 ACTIVITY_INTENSITY，这是一种根据世界卫生组织关于中等强度和剧烈强度活动的指南定义的数据类型。每个记录都需要提供开始时间、结束时间以及活动强度（中等或剧烈）。

Health Connect 还包含支持医疗记录的更新版 API。这样一来，应用便可在征得用户明确同意的情况下，读取和写入 FHIR 格式的医疗记录。

Privacy Sandbox on Android

Android 16 incorporates the latest version of the Privacy Sandbox on Android, part of our ongoing work to develop technologies where users know their privacy is protected. Our website has more about the Privacy Sandbox on Android developer beta program to help you get started. Check out the SDK Runtime which allows SDKs to run in a dedicated runtime environment separate from the app they are serving, providing stronger safeguards around user data collection and sharing.

安全

Android 16 包含有助于增强应用安全性和保护应用数据的功能。

密钥共享 API

Android 16 添加了一些 API，这些 API 支持与其他应用共享对 Android Keystore 密钥的访问权限。新的 KeyStoreManager 类支持按应用 uid 授予和撤消对密钥的访问权限，并包含一个供应用访问共享密钥的 API。

设备规格

Android 16 为您的应用提供支持，让您充分利用 Android 的设备类型。

电视的标准化画质和音质框架

The new MediaQuality package in Android 16 exposes a set of standardized APIs for access to audio and picture profiles and hardware-related settings. This allows streaming apps to query profiles and apply them to media dynamically:

  • Movies mastered with a wider dynamic range require greater color accuracy to see subtle details in shadows and adjust to ambient light, so a profile that prefers color accuracy over brightness may be appropriate.
  • Live sporting events are often mastered with a narrow dynamic range, but are often watched in daylight, so a profile that preferences brightness over color accuracy can give better results.
  • Fully interactive content wants minimal processing to reduce latency, and wants higher frame rates, which is why many TV's ship with a game profile.

The API allows apps to switch between profiles and users to enjoy tuning supported TVs to best suit their content.

国际化

Android 16 新增了多项功能，可在设备以不同语言运行时提升用户体验。

竖排文字

Android 16 添加了对垂直渲染和测量文本的低级支持，以便为库开发者提供基本的垂直书写支持。这对于日语等通常使用竖向书写系统的语言特别有用。Paint 类中添加了一个新标志 VERTICAL_TEXT_FLAG。使用 Paint.setFlags 设置此标志后，Paint 的文本测量 API 将报告垂直进度，而不是水平进度，并且 Canvas 将垂直绘制文本。

val text = "「春は、曙。」"
Box(
    Modifier.padding(innerPadding).background(Color.White).fillMaxSize().drawWithContent {
        drawIntoCanvas { canvas ->
            val paint = Paint().apply { textSize = 64.sp.toPx() }
            // Draw text vertically
            paint.flags = paint.flags or VERTICAL_TEXT_FLAG
            val height = paint.measureText(text)
            canvas.nativeCanvas.drawText(
                text,
                0,
                text.length,
                size.width / 2,
                (size.height - height) / 2,
                paint
            )
        }
    }
) {}

自定义度量衡制

Users can now customize their measurement system in regional preferences within Settings. The user preference is included as part of the locale code, so you can register a BroadcastReceiver on ACTION_LOCALE_CHANGED to handle locale configuration changes when regional preferences change.

Using formatters can help match the local experience. For example, "0.5 in" in English (United States), is "12,7 mm" for a user who has set their phone to English (Denmark) or who uses their phone in English (United States) with the metric system as the measurement system preference.

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