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，则应根据情况修改应用，以支持这些行为。

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。

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 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.

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 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.

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

In Android 17, the platform continues its shift toward a "secure-by-default" architecture, introducing a suite of enhancements designed to mitigate high-severity exploits such as phishing, interaction hijacking, and confused deputy attacks. This update requires developers to explicitly opt in to new security standards to maintain app compatibility and user protection.

Key impacts for developers include:

  • BAL hardening & improved opt-in: We are refining Background Activity Launch (BAL) restrictions by extending protections to IntentSender. Developers must migrate away from the legacy MODE_BACKGROUND_ACTIVITY_START_ALLOWED constant. Instead, you should adopt granular controls like MODE_BACKGROUND_ACTIVITY_START_ALLOW_IF_VISIBLE, which restricts activity starts to scenarios where the calling app is visible, significantly reducing the attack surface.
  • Adoption tools: Developers should utilize strict mode and updated lint checks to identify legacy patterns and ensure readiness for future target SDK requirements.

本地主机保护

To improve platform security and user privacy, Android 17 introduces a new install-time permission, USE_LOOPBACK_INTERFACE. This change restricts cross-app and cross-profile communication over the loopback interface (for example, 127.0.0.1 or ::1), which was previously implicitly allowed with the INTERNET permission. For apps targeting Android 17 or higher, the following rules apply:

  • Mutual consent required: cross-app and cross-profile communication is now blocked by default. For a connection to succeed, both the sending app and the receiving app must explicitly declare the USE_LOOPBACK_INTERFACE permission in their manifests.
  • Intra-app traffic exempt: Loopback communication within the same app (intra-app communication) remains unaffected and does not require this new permission.
  • Target SDK behavior:
    • App targets Android 17 or higher: The permission must be explicitly requested. If it is missing, socket operations (such as TCP connect or UDP send) fail, typically returning an EPERM (operation not permitted) error.
    • App targets API level 36 or lower: The permission is treated as a split permission on INTERNET. Apps targeting lower API levels are auto-granted this permission if they hold INTERNET.
  • Compatibility warning: If a receiving app updates its target to Android 17 but fails to request this permission, incoming connections from other apps are be rejected, even if the sending app targets a lower API level.

默认启用 CT

If an app targets Android 17 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

如果您的应用以 Android 17 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。

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，用于忽略大屏设备 (sw>=600dp) 上的屏幕方向、尺寸调整能力和宽高比限制

We introduced Platform API changes in Android 16 to ignore orientation, aspect ratio, and resizability restrictions on large screens (sw >= 600dp) for apps targeting API level 36 or higher. Developers have the option to opt out of these changes with SDK 36, but this opt-out will no longer be available for apps that target Android 17 or higher.

For more information, see Restrictions on orientation and resizability are ignored.