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功能和 API

Android 17 面向开发者引入了一些出色的新功能和 API。以下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 17 添加了以下与 Android 核心功能相关的新功能。

新的 ProfilingManager 触发器

Android 17 adds several new system triggers to ProfilingManager to help you collect in-depth data to debug performance issues.

The new triggers are:

TRIGGER_TYPE_COLD_START: Trigger occurs during app cold start. It provides both a call stack sample and a system trace in the response.
TRIGGER_TYPE_OOM: Trigger occurs when an app throws an OutOfMemoryError and provides a Java Heap Dump in response.
TRIGGER_TYPE_KILL_EXCESSIVE_CPU_USAGE: Trigger occurs when an app is killed due to abnormal and excessive CPU usage and provides a snapshot of a running background system trace in response.
TRIGGER_TYPE_ANOMALY: Detect system performance anomalies such as excessive binder calls and excessive memory usage.

To understand how to set up the system trigger, see the documentation on trigger-based profiling and how to retrieve and upload profiles and analyze profiling data.

Profiling trigger for app anomalies

Android 17 introduces an on-device anomaly detection service that monitors for resource-intensive behaviors and potential compatibility regressions. Integrated with ProfilingManager, this service allows your app to receive profiling artifacts triggered by specific system-detected events.

Use the TRIGGER_TYPE_ANOMALY trigger to detect system performance issues such as excessive binder calls and excessive memory usage. When an app breaches OS-defined memory limits, the anomaly trigger allows developers to receive app-specific heap dumps to help identify and fix memory issues. Additionally, for excessive binder spam, the anomaly trigger provides a stack sampling profile on binder transactions.

This API callback occurs prior to any system imposed enforcements. For example, it can help developers collect debug data before the app is terminated by the system for exceeding memory limits.

fun registerAnomalyTrigger(context: Context) {
    val profilingManager =
        context.getSystemService(ProfilingManager::class.java) ?: return
    val triggers = listOf(
        ProfilingTrigger.Builder(ProfilingTrigger.TRIGGER_TYPE_ANOMALY).build()
    )
    val callbackExecutor: Executor = Executors.newSingleThreadExecutor()
    val resultCallback = Consumer<ProfilingResult> { profilingResult ->
        if (profilingResult.errorCode == ProfilingResult.ERROR_NONE) {
            // Upload profile result to server for further analysis
            profilingResult.resultFilePath?.let { setupProfileUploadWorker(it) }
        }
    }
    profilingManager.registerForAllProfilingResults(
        callbackExecutor,
        resultCallback
    )
    profilingManager.addProfilingTriggers(triggers)
}

JobDebugInfo API

Android 17 引入了新的 JobDebugInfo API，可帮助开发者调试其 JobScheduler 作业，例如作业未运行的原因、作业运行了多长时间以及其他聚合信息。

扩展后的 JobDebugInfo API 的第一个方法是 getPendingJobReasonStats()，它会返回一个映射，其中包含作业处于待执行状态的原因及其各自的累计待处理时长。此方法结合了 getPendingJobReasonsHistory() 和 getPendingJobReasons() 方法，可让您深入了解预定作业未按预期运行的原因，但通过在单个方法中提供时长和作业原因，简化了信息检索。

例如，对于指定的 jobId，该方法可能会返回 PENDING_JOB_REASON_CONSTRAINT_CHARGING 和 60000 毫秒的时长，表示由于充电限制未得到满足，作业处于待处理状态的时长为 60000 毫秒。

通过监听器支持“空闲时允许”闹钟，减少唤醒锁定

Android 17 introduces a new variant of AlarmManager.setExactAndAllowWhileIdle that accepts an OnAlarmListener instead of a PendingIntent. This new callback-based mechanism is ideal for apps that currently rely on continuous wakelocks to perform periodic tasks, such as messaging apps maintaining socket connections.

隐私权

Android 17 包含以下新功能，可更好地保护用户隐私。

加密客户端 Hello (ECH) 平台支持

Android 17 引入了对加密客户端 Hello (ECH) 的平台支持，这是对网络通信的一项重大隐私增强功能。ECH 是一项 TLS 1.3 扩展，可在初始 TLS 握手期间加密服务器名称指示 (SNI)。这种加密有助于保护用户隐私，因为它可以让网络中介更难识别应用连接到的特定网域。

该平台现在包含网络库实现 ECH 所需的 API。这包括 DnsResolver 中的新功能，用于查询包含 ECH 配置的 HTTPS DNS 记录；以及 Conscrypt 的 SSLEngine 和 SSLSocket 中的新方法，用于在连接到网域时传入这些配置来启用 ECH。开发者可以通过网络安全配置文件中的新 <domainEncryption> 元素来配置 ECH 偏好设置，例如机会性地启用 ECH 或强制使用 ECH，这些设置可全局应用，也可按网域应用。

预计 HttpEngine、WebView 和 OkHttp 等热门联网库将在未来的更新中集成这些平台 API，从而使应用能够更轻松地采用 ECH 并增强用户隐私保护。

如需了解详情，请参阅加密的客户端 Hello 文档。

Android 联系人选择工具

The Android Contact Picker is a standardized, browsable interface for users to share contacts with your app. Available on devices running Android 17 (API level 37) or higher, the picker offers a privacy-preserving alternative to the broad READ_CONTACTS permission. Instead of requesting access to the user's entire address book, your app specifies the data fields it needs, such as phone numbers or email addresses, and the user selects specific contacts to share. This grants your app read access to only the selected data, ensuring granular control while providing a consistent user experience with built-in search, profile switching, and multi-selection capabilities without having to build or maintain the UI.

For more information, see the contact picker documentation.

安全

Android 17 添加了以下新功能，以提高设备和应用的安全性。

Android 高级保护模式 (AAPM)

Android 高级保护模式为 Android 用户提供了一套强大的新安全功能，标志着在保护用户（尤其是面临较高风险的用户）免遭复杂攻击方面迈出了重要一步。AAPM 是一项选择启用功能，只需进行一项配置设置即可激活。用户可以随时启用该功能，以应用一套主观的安全保护措施。

这些核心配置包括：禁止安装未知来源的应用（旁加载）、限制 USB 数据信号传输，以及强制执行 Google Play 保护机制扫描，从而显著减小设备的攻击面。开发者可以使用 AdvancedProtectionManager API 与此功能集成，以检测模式的状态，从而使应用能够在用户选择启用此模式时自动采用强化型安全姿态或限制高风险功能。

PQC APK 签名

Android 现在支持混合 APK 签名方案，可保护应用的签名身份免受利用量子计算的潜在攻击威胁。此功能引入了一种新的 APK 签名方案，可让您将传统签名密钥（例如 RSA 或 EC）与新的后量子加密 (PQC) 算法 (ML-DSA) 搭配使用。

这种混合方法可确保您的应用在未来免受量子攻击，同时与依赖经典签名验证的旧版 Android 和设备保持完全向后兼容。

对开发者的影响

使用 Play 应用签名的应用：如果您使用 Play 应用签名，则可以等待 Google Play 为您提供使用 Google Play 生成的 PQC 密钥升级混合签名的选项，从而确保您的应用受到保护，而无需手动管理密钥。
使用自行管理密钥的应用：自行管理签名密钥的开发者可以利用更新后的 Android 构建工具（例如 apksigner）轮替到混合身份，将 PQC 密钥与新的经典密钥相结合。（您必须创建新的传统密钥，不能重复使用旧密钥。）

连接

Android 17 添加了以下功能，以改进设备和应用连接。

受限卫星网络

实现优化，使应用能够在低带宽卫星网络上有效运行。

用户体验和系统界面

Android 17 包含以下旨在提升用户体验的变更。

专用 Google 助理音量流

Android 17 introduces a dedicated Assistant volume stream for Assistant apps, for playback with USAGE_ASSISTANT. This change decouples Assistant audio from the standard media stream, providing users with isolated control over both volumes. This enables scenarios such as muting media playback while maintaining audibility for Assistant responses, and the other way around.

Assistant apps with access to the new MODE_ASSISTANT_CONVERSATION audio mode can further improve the volume control consistency. Assistant apps can use this mode to provide a hint to the system about an active Assistant session, ensuring the Assistant stream can be controlled outside of the active USAGE_ASSISTANT playback or with connected Bluetooth peripherals.

Handoff

Handoff is a new feature and API coming to Android 17 that app developers can integrate with to provide cross-device continuity for their users. It allows the user to start an app activity on one Android device and transition it to another Android device. Handoff runs in the background of a user's device and surfaces available activities from the user's other nearby devices through various entry points, like the launcher and taskbar, on the receiving device.

Apps can designate Handoff to launch the same native Android app, if it is installed and available on the receiving device. In this app-to-app flow, the user is deep-linked to the designated activity. Alternatively, app-to-web Handoff can be offered as a fallback option or directly implemented with URL Handoff.

Handoff support is implemented on a per-activity basis. To enable Handoff, call the setHandoffEnabled() method for the activity. Additional data may need to be passed along with the handoff so the recreated activity on the receiving device can restore appropriate state. Implement the onHandoffActivityDataRequested() callback to return a HandoffActivityData object which contains details that specify how Handoff should handle and recreate the activity on the receiving device.

实时动态 - 语义颜色 API

在 Android 17 中，实时动态推出了语义着色 API，以支持具有通用含义的颜色。

以下类支持语义着色：

填色游戏

绿色：与安全相关。此颜色应在让用户知道您处于安全情况时使用。
橙色：用于表示警告和标记物理危险。当用户需要注意设置更好的保护设置时，应使用此颜色。
红色：通常表示危险、停止。它应该在需要人们紧急关注的情况下显示。
蓝色：中性色，用于提供信息且应从其他内容中脱颖而出的内容。

以下示例展示了如何将语义样式应用于通知中的文本：

  val ssb = SpannableStringBuilder()
        .append("Colors: ")
        .append("NONE", Notification.createSemanticStyleAnnotation(SEMANTIC_STYLE_UNSPECIFIED), 0)
        .append(", ")
        .append("INFO", Notification.createSemanticStyleAnnotation(SEMANTIC_STYLE_INFO), 0)
        .append(", ")
        .append("SAFE", Notification.createSemanticStyleAnnotation(SEMANTIC_STYLE_SAFE), 0)
        .append(", ")
        .append("CAUTION", Notification.createSemanticStyleAnnotation(SEMANTIC_STYLE_CAUTION), 0)
        .append(", ")
        .append("DANGER", Notification.createSemanticStyleAnnotation(SEMANTIC_STYLE_DANGER), 0)

    Notification.Builder(context, channelId)
          .setSmallIcon(R.drawable.ic_icon)
          .setContentTitle("Hello World!")
          .setContentText(ssb)
          .setOngoing(true)
              .setRequestPromotedOngoing(true)

适用于 Android 17 的 UWB Downlink-TDoA API

Downlink Time Difference of Arrival (DL-TDoA) ranging lets a device determine its position relative to multiple UWB anchors by measuring the relative arrival times of signals.

For more information and code samples, see UWB Downlink-TDoA API.