行为变更：以 Android 17 或更高版本为目标平台的应用

与之前的版本一样，Android 17 包含一些可能会影响应用的行为变更。以下行为变更仅影响以 Android 17 或更高版本为目标平台的应用。如果您的应用以 Android 17 或更高版本为目标平台，您应该修改自己的应用以支持这些行为（如果适用）。

无论应用的 targetSdkVersion 为何，都请务必查看对 Android 17 上运行的所有应用都有影响的行为变更列表。

注意： 本页列出了一些比较重要的变更。如需了解更多详细信息，请参阅 Android 17 版本说明。

用户体验和系统界面

Android 17 包含以下旨在打造更一致、更直观的用户体验的变更。

内存限制 widget

Beginning with Android 17, for apps targeting Android 17 (API level 37) or higher, the system enforces a strict memory limit (1.5 * screen width * screen height * 4) against the combined memory usage of both Bitmaps and Icons present in the RemoteViews parcel. Exceeding these limits throws a fatal IllegalArgumentException and crashes the app's process.

For more information, see UpdateAppWidget.

核心功能

Android 17 包含以下变更，这些变更会修改或扩展 Android 系统的各种核心功能。

MessageQueue 的新无锁实现

Beginning with Android 17, apps targeting Android 17 (API level 37) or higher receive a new lock-free implementation of android.os.MessageQueue. The new implementation improves performance and reduces missed frames, but may break clients that reflect on MessageQueue private fields and methods.

For more information, including mitigation strategies, see MessageQueue behavior change guidance.

静态 final 字段现在不可修改

Apps running on Android 17 or higher that target Android 17 (API level 37) or higher cannot change static final fields. If an app attempts to change a static final field by using reflection, it will cause an IllegalAccessException. Attempting to modify one of these fields through JNI APIs (such as SetStaticLongField()) will cause the app to crash.

无障碍

Android 17 进行了以下变更，以改进无障碍功能。

复杂 IME 实体键盘输入的无障碍支持

This feature introduces new AccessibilityEvent and TextAttribute APIs to enhance screen reader spoken feedback for CJKV language input. CJKV IME apps can now signal whether a text conversion candidate has been selected during text composition. Apps with edit fields can specify text change types when sending text changed accessibility events. For example, apps can specify that a text change occurred during text composition, or that a text change resulted from a commit. Doing this enables accessibility services such as screen readers to deliver more precise feedback based on the nature of the text modification.

App adoption

• IME Apps: When setting composing text in edit fields, IMEs can use TextAttribute.Builder.setTextSuggestionSelected() to indicate whether a specific conversion candidate was selected.

• Apps with Edit Fields: Apps that maintain a custom InputConnection can retrieve candidate selection data by calling TextAttribute.isTextSuggestionSelected(). These apps should then call AccessibilityEvent.setTextChangeTypes() when dispatching TYPE_VIEW_TEXT_CHANGED events. Apps targeting Android 17 (API level 37) that use the standard TextView will have this feature enabled by default. (That is, TextView will handle retrieving data from the IME and setting text change types when sending events to accessibility services).

• Accessibility Services: Accessibility services that process TYPE_VIEW_TEXT_CHANGED events can call AccessibilityEvent.getTextChangeTypes() to identify the nature of the modification and adjust their feedback strategies accordingly.

隐私权

Android 17 包含以下变更，旨在提升用户隐私保护。

已启用 ECH（加密客户端 Hello）

Android 17 introduces platform support for Encrypted Client Hello (ECH), a TLS extension that enhances user privacy by encrypting the Server Name Indication (SNI) in the TLS handshake. This encryption helps prevent network observers from easily identifying the specific domain your app is connecting to.

For apps targeting Android 17 (API level 37) or higher, ECH is used for TLS connections. ECH is active only if the networking library used by the app (for example, HttpEngine, WebView, or OkHttp) has integrated ECH support and the remote server also supports the ECH protocol. If ECH cannot be negotiated, the client sends an ECH extension with randomized contents (a mechanism called ECH GREASE). See RFC 9849 for more details on how ECH GREASE works.

To allow apps to customize this behavior, Android 17 adds a new <domainEncryption> element to the Network Security Configuration file. Developers can use <domainEncryption> within <base-config> or <domain-config> tags to select an ECH mode (for example, "enabled" or "disabled") on a global or per-domain basis.

For more information, see the Encrypted Client Hello documentation.

以 Android 17 为目标平台的应用需要本地网络权限

Android 17 introduces the ACCESS_LOCAL_NETWORK runtime permission to protect users from unauthorized local network access. Because this falls under the existing NEARBY_DEVICES permission group, users who have already granted other NEARBY_DEVICES permissions aren't prompted again. This new requirement prevents malicious apps from exploiting unrestricted local network access for covert user tracking and fingerprinting. By declaring and requesting this permission, your app can discover and connect to devices on the local area network (LAN), such as smart home devices or casting receivers.

Apps targeting Android 17 (API level 37) or higher now have two paths to maintain communication with LAN devices: Adopt system-mediated, privacy-preserving device pickers to skip the permission prompt, or explicitly request this new permission at runtime to maintain local network communication.

For more information, see the Local network permission documentation.

Note: In Android 16, apps could opt in to local network permissions. Beginning with Android 17, enforcement is mandatory for apps that target Android 17 (API level 37) or higher.

在实体设备上隐藏密码

If an app targets Android 17 (API level 37) or higher and the user is using a physical input device (for example, an external keyboard), the Android operating system applies the new show_passwords_physical setting to all characters in the password field. By default, that setting hides all password characters.

The Android system shows the last-typed password character to help the user see if they mistyped the password. However, this is much less necessary with larger external keyboards. In addition, devices with external keyboards often have larger displays, which increases the danger of someone seeing the typed password.

If the user is using the device's touchscreen, the system applies the new show_passwords_touch setting.

针对标准短信的 OTP 保护

从 Android 17 开始，Android 将扩展其短信动态密码保护功能，以适用于标准短信（包含未使用 WebOTP 或 SMS Retriever 格式的动态密码的短信）。对于以 Android 17（API 级别 37）或更高版本为目标平台的大多数应用，这些短信在收到后三小时内无法使用。此延迟旨在帮助防止 OTP 劫持。在这 3 小时的延迟期间，SMS_RECEIVED_ACTION 广播会被保留，并且 SMS 提供方数据库查询会被过滤。延迟结束后，这些应用即可访问相应短信。

某些应用（例如默认的短信助理应用、已连接的设备配套应用等）不受此延迟限制。所有依赖于读取短信消息来提取 OTP 的应用都应改用 SMS Retriever 或 SMS User Consent API，以确保功能能够继续正常运行。

注意： 针对 WebOTP 和 SMS Retriever 格式的消息提供的额外 SMS OTP 保护适用于所有应用，与其目标 API 级别无关。如需了解详情，请参阅所有应用的重大行为变更文档中的 SMS OTP 保护。

安全

Android 17 对设备和应用安全性进行了以下改进。

活动安全性

在 Android 17 中，平台继续向“默认安全”架构转变，引入了一系列旨在缓解严重程度较高的漏洞利用（例如网络钓鱼、交互劫持和混淆代理攻击）的增强功能。此更新要求开发者明确选择启用新的安全标准，以保持应用兼容性和用户保护。

对开发者的主要影响包括：

• BAL 安全加固和改进的选择启用机制：我们正在通过将保护范围扩展到 IntentSender 来完善后台 Activity 启动 (BAL) 限制。开发者必须弃用旧版 MODE_BACKGROUND_ACTIVITY_START_ALLOWED 常量。相反，您应采用精细的控制措施，例如 MODE_BACKGROUND_ACTIVITY_START_ALLOW_IF_VISIBLE，该措施会将 activity 启动限制在调用应用可见的场景中，从而显著减小攻击面。
• 采用工具：开发者应利用严格模式和更新后的 lint 检查来识别旧版模式，并确保应用符合未来的目标 SDK 要求。

默认启用 CT

If an app targets Android 17 (API level 37) or higher, certificate transparency (CT) is enabled by default. (On Android 16, CT is available but apps had to opt in.)

更安全的原生 DCL - C

If your app targets Android 17 (API level 37) or higher, the Safer Dynamic Code Loading (DCL) protection introduced in Android 14 for DEX and JAR files now extends to native libraries.

All native files loaded using System.load() must be marked as read-only. Otherwise, the system throws UnsatisfiedLinkError.

We recommend that apps avoid dynamically loading code whenever possible, as doing so greatly increases the risk that an app can be compromised by code injection or code tampering.

限制 CP2 数据视图中的 PII 字段

For apps targeting Android 17 (API level Android 17 (API level 37)) and higher, Contacts Provider 2 (CP2) restricts certain columns containing Personally Identifiable Information (PII) from the data view. When this change is enabled, these columns are removed from the data view to enhance user privacy. The restricted columns include:

• ACCOUNT_NAME
• ACCOUNT_TYPE
• ACCOUNT_TYPE_AND_DATA_SET

Apps that are using these columns from ContactsContract.Data can extract them from ContactsContract.RawContacts instead, by joining with RAW_CONTACT_ID.

在 CP2 中强制执行严格的 SQL 检查

For apps targeting Android 17 (API level Android 17 (API level 37)) and higher, Contacts Provider 2 (CP2) enforces strict SQL query validation when the ContactsContract.Data table is accessed without READ_CONTACTS permission.

With this change, if an app doesn't have READ_CONTACTS permission, StrictColumns and StrictGrammar options are set when querying the ContactsContract.Data table. If a query uses a pattern that isn't compatible with these, it will be rejected and cause an exception to be thrown.

智能

Android 17 针对系统智能做出了以下变更。

弃用 setContentCaptureEnabled

某些设备默认启用内容捕获功能，以便设备端 AI 功能分析屏幕内容，从而提供智能体验。

从 Android 17 开始，ContentCaptureManager.setContentCaptureEnabled(boolean) API 方法已被废弃。对于以 Android 17（API 级别 37）或更高版本为目标平台的应用，调用 setContentCaptureEnabled(false) 不再停用内容捕获。

如果您的应用需要继续停用内容捕获或限制系统捕获屏幕内容，则必须改用 FLAG_SECURE 窗口布局参数。

如需停用内容捕获，请在窗口上设置 FLAG_SECURE 标志，如以下示例所示：

Kotlin

window.setFlags(
    WindowManager.LayoutParams.FLAG_SECURE,
    WindowManager.LayoutParams.FLAG_SECURE
)

Java

getWindow().setFlags(
    WindowManager.LayoutParams.FLAG_SECURE,
    WindowManager.LayoutParams.FLAG_SECURE
);

如需了解详情，请参阅 WindowManager.LayoutParams.FLAG_SECURE 参考文档。

媒体

Android 17 针对媒体行为做了以下更改。

后台音频安全加固

Beginning with Android 17, the audio framework enforces restrictions on background audio interactions including audio playback, audio focus requests, and volume change APIs to ensure that these changes are started intentionally by the user.

Some audio restrictions apply to all apps. However, the restrictions are more stringent if an app targets Android 17 (API level 37). If one of these apps interacts with audio while it is in the background, it must have a foreground service running. In addition, the app must meet one or both of these requirements:

• The foreground service must have while-in-use (WIU) capabilities.
• The app must have the exact alarm permission and be interacting with USAGE_ALARM audio streams.

For more information, including mitigation strategies, see Background audio hardening.

设备规格

Android 17 包含以下变更，可改善各种尺寸和外形规格的设备上的用户体验。

平台 API 变更：忽略大屏设备 (sw>=600dp) 上的屏幕方向、尺寸调整和宽高比限制

我们在 Android 16 中引入了平台 API 变更，以忽略以 API 级别 36 或更高级别为目标的应用在大屏 (sw >= 600dp) 设备上的屏幕方向、宽高比和尺寸调整能力限制。开发者可以选择使用 SDK 36 停用这些变更，但对于以 Android 17（API 级别 37）或更高版本为目标平台的应用，此停用选项将不再可用。

如需了解详情，请参阅忽略了有关屏幕方向和可调整大小性的限制。

连接

Android 17 引入了以下变更，以提高一致性并与蓝牙 RFCOMM 套接字的标准 Java InputStream 行为保持一致。

针对 RFCOMM 的一致 BluetoothSocket read() 行为

对于以 Android 17（API 级别 37）为目标平台的应用，从基于 RFCOMM 的 BluetoothSocket 获取的 InputStream 的 read() 方法现在在套接字关闭或连接断开时返回 -1。

此变更使 RFCOMM 套接字行为与 LE CoC 套接字保持一致，并与标准 InputStream.read() 文档保持一致，该文档指出，当到达数据流末尾时，系统会返回 -1。

仅依靠捕获 IOException 来跳出读取循环的应用可能会受到此变更的影响，应更新 BluetoothSocket 读取循环以明确检查 -1 的返回值。这可确保在远程设备断开连接或套接字关闭时，循环正确终止。如需查看推荐的实现示例，请参阅传输蓝牙数据指南中的代码段。