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 引入了 ACCESS_LOCAL_NETWORK 运行时权限，以保护用户免遭未经授权的本地网络访问。由于此权限属于现有的 NEARBY_DEVICES 权限组，因此已授予其他 NEARBY_DEVICES 权限的用户不会再次收到提示。这项新要求可防止恶意应用利用不受限制的本地网络访问权限进行隐蔽的用户跟踪和指纹识别。通过声明和请求此权限，您的应用可以发现并连接到局域网 (LAN) 中的设备，例如智能家居设备或投屏接收器。

以 Android 17（API 级别 37）或更高版本为目标平台的应用现在可以通过两种方式与 LAN 设备保持通信：采用系统介导的、可保护隐私的设备选择器来跳过权限提示，或者在运行时明确请求这项新权限来保持本地网络通信。

如需了解详情，请参阅本地网络权限文档。

注意： 在 Android 16 中，应用可以选择启用本地网络权限。 自 Android 17 起，对于以 Android 17（API 级别 37）或更高版本为目标平台的应用，强制执行此项检查。

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

Beginning with Android 17, Android is extending its SMS OTP protection to apply to standard SMS messages (SMS messages containing an OTP that do not use the WebOTP or SMS Retriever formats). For most apps targeting Android 17 (API level 37) or higher, these SMS messages do not become available until three hours after receipt. This delay is intended to help prevent OTP hijacking. During this three hour delay, the SMS_RECEIVED_ACTION broadcast is withheld and SMS provider database queries are filtered. The SMS message is available to these apps after the delay.

Certain apps such as the default SMS assistant app, connected device companion apps, etc., are exempted from this delay. All apps that rely on reading SMS messages for OTP extraction should transition to using SMS Retriever or SMS User Consent APIs to ensure continued functionality.

Note: Additional SMS OTP protections for WebOTP and SMS Retriever format messages apply to all apps, regardless of their target API level. For more information, see SMS OTP protection in the Behavior changes for all apps documentation.

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

如果应用以 Android 17（API 级别 37）或更高版本为目标平台，则默认启用证书透明度 (CT)。（在 Android 16 上，CT 可用，但应用必须选择启用。）

更安全的原生 DCL - C

如果您的应用以 Android 17（API 级别 37）或更高版本为目标平台，则 Android 14 中针对 DEX 和 JAR 文件引入的更安全的动态代码加载 (DCL) 保护功能现在也适用于原生库。

使用 System.load() 加载的所有原生文件都必须标记为只读。 否则，系统会抛出 UnsatisfiedLinkError。

我们建议应用尽可能避免动态加载代码，因为这样做会大大增加应用因代码注入或代码篡改而遭到入侵的风险。

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

对于以 Android 17（API 级别 37）及更高版本为目标平台的应用，当在没有 READ_CONTACTS 权限的情况下访问 ContactsContract.Data 表时，联系人提供程序 2 (CP2) 会强制执行严格的 SQL 查询验证。

在此更改之后，如果应用没有 READ_CONTACTS 权限，则在查询 ContactsContract.Data 表时，系统会设置 StrictColumns 和 StrictGrammar 选项。如果查询使用的模式与这些模式不兼容，则会被拒绝并导致抛出异常。

智能

Android 17 针对系统智能做出了以下变更。

弃用 setContentCaptureEnabled

Content Capture is enabled by default on certain devices to allow on-device AI features to analyze screen contents for intelligent experiences.

Starting in Android 17, the ContentCaptureManager.setContentCaptureEnabled(boolean) API method is deprecated. For apps that target Android 17 (API level 37) or higher, calling setContentCaptureEnabled(false) no longer disables Content Capture.

If your app needs to continue disabling Content Capture or restrict screen contents from being captured by the system, you must transition to using the FLAG_SECURE window layout parameter.

To disable Content Capture, set the FLAG_SECURE flag on your window as shown in the following example:

Kotlin

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

Java

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

For more details, see the WindowManager.LayoutParams.FLAG_SECURE reference documentation.

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

For apps targeting Android 17 (API level 37), the read() method of the InputStream obtained from an RFCOMM-based BluetoothSocket now returns -1 when the socket is closed or the connection is dropped.

This change makes RFCOMM socket behavior consistent with LE CoC sockets and aligns with the standard InputStream.read() documentation, which states that -1 is returned when the end of the stream is reached.

Apps that rely solely on catching an IOException to break out of a read loop may be impacted by this change and should update the BluetoothSocket read loops to explicitly check for a return value of -1. This ensures the loop terminates correctly when the remote device disconnects or the socket is closed. For an example of the recommended implementation, see the code snippet in the Transfer Bluetooth data guide.