行為變更：所有應用程式

Android 17 平台包含可能對應用程式造成影響的行為變更。無論 targetSdkVersion 為何，凡是在 Android 17 上執行的應用程式，「一律」都會受到下列行為變更所影響。您必須測試自己的應用程式，並視需要進行修改，以便在適當情況下支援這些變更。

另請務必查看僅對指定 Android 17 為目標版本的應用程式造成影響的行為變更。

核心功能

Android 17 (API 級別 37) 包含下列異動項目，這類變更會修改或擴充 Android 系統的各種核心功能。

應用程式記憶體限制

Android 17 introduces app memory limits based on the device's total RAM to create a more stable and deterministic environment for your applications and Android users. In Android 17, limits are set conservatively to establish system baselines, targeting extreme memory leaks and other outliers before they trigger system-wide instability resulting in UI stuttering, higher battery drain, and apps being killed. While we anticipate minimal impact on the vast majority of app sessions, we recommend the following memory best practices, including establishing a baseline for memory.

You can determine if your app session was impacted by calling getDescription in ApplicationExitInfo; if your app was affected, the exit reason will be REASON_OTHER and the description will contain the string "MemoryLimiter:AnonSwap" along with other information. You can also use trigger-based profiling with TRIGGER_TYPE_ANOMALY to get heap dumps that are collected when the memory limit is hit.

The LeakCanary task in the Android Studio Profiler.

To help you find memory leaks, Android Studio Panda adds LeakCanary integration directly in the Android Studio Profiler as a dedicated task, contextualized within the IDE and fully integrated with your source code.

安全性

Android 17 包含下列裝置和應用程式安全性改善項目。

usesClearTraffic 淘汰計畫

我們計畫在日後推出的版本中淘汰 usesCleartextTraffic 元素。 如果應用程式需要建立未加密 (HTTP) 連線，請改用網路安全性設定檔，指定應用程式需要建立明文連線的網域。

請注意，網路安全性設定檔僅適用於 API 級別 24 以上版本。如果應用程式的最低 API 級別低於 24，請同時執行下列操作：

  • 將 usesCleartextTraffic 屬性設為 true
  • 使用網路設定檔

如果應用程式的最低 API 級別為 24 以上，您可以使用網路設定檔，不必設定 usesCleartextTraffic。

限制隱含 URI 授權

目前，如果應用程式啟動的意圖含有動作 Send、SendMultiple 或 ImageCapture 的 URI，系統會自動授予目標應用程式讀取和寫入 URI 的權限。我們計畫在 Android 18 中變更這項行為。因此，建議應用程式明確授予相關 URI 權限，而非依賴系統授予權限。

每個應用程式的 Keystore 限制

Apps should avoid creating excessive numbers of keys in Android Keystore, because it is a shared resource for all apps on the device. Beginning with Android 17, the system enforces a limit on the number of keys an app can own. The limit is 50,000 keys for non-system apps targeting Android 17 (API level 37) or higher, and 200,000 keys for all other apps. System apps have a limit of 200,000 keys, regardless of which API level they target.

If an app attempts to create keys beyond the limit, the creation fails with a KeyStoreException. The exception's message string contains information about the key limit. If the app calls getNumericErrorCode() on the exception, the return value depends on what API level the app targets:

  • Apps targeting Android 17 (API level 37) or higher: getNumericErrorCode() returns the new ERROR_TOO_MANY_KEYS value.
  • All other apps: getNumericErrorCode() returns ERROR_INCORRECT_USAGE.

使用者體驗和系統 UI

Android 17 包含下列變更，目的是為了打造更一致、直覺的使用者體驗。

裝置旋轉後自動恢復預設的 IME 版面空間

從 Android 17 開始，如果裝置設定變更 (例如旋轉) 並非由應用程式本身處理，系統就不會還原先前的輸入法編輯器瀏覽權限。

如果應用程式發生未處理的設定變更，且變更後需要顯示鍵盤，您必須明確提出要求。您可以透過下列方式提出要求：

  • 將 android:windowSoftInputMode 屬性設為 stateAlwaysVisible。
  • 在活動的 onCreate() 方法中，以程式輔助方式要求顯示螢幕鍵盤，或新增 onConfigurationChanged() 方法。

手動輸入

Android 17 包含下列異動項目，這些變更會影響應用程式與鍵盤和觸控板等人類輸入裝置的互動方式。

在指標擷取期間，觸控板預設會傳送相對事件

Beginning with Android 17, if an app requests pointer capture using View.requestPointerCapture() and the user uses a touchpad, the system recognizes pointer movement and scrolling gestures from the user's touches and reports them to the app in the same way as pointer and scroll wheel movements from a captured mouse. In most cases, this removes the need for apps that support captured mice to add special handling logic for touchpads. For more details, see the documentation for View.POINTER_CAPTURE_MODE_RELATIVE.

Previously, the system did not attempt to recognize gestures from the touchpad, and instead delivered the raw, absolute finger locations to the app in a similar format to touchscreen touches. If an app still requires this absolute data, it should call the new View.requestPointerCapture(int) method with View.POINTER_CAPTURE_MODE_ABSOLUTE instead.

媒體

Android 17 包含下列媒體行為變更。

背景音訊強化

從 Android 17 開始，音訊架構會強制限制背景音訊互動，包括音訊播放、音訊焦點要求和音量變更 API，確保這些變更是由使用者刻意啟動。

如果應用程式嘗試在無效的生命週期呼叫音訊 API，音訊播放和音量變更 API 會無聲無息地失敗，不會擲回例外狀況或提供失敗訊息。音訊焦點 API 失敗，結果代碼為 AUDIOFOCUS_REQUEST_FAILED。

如需更多資訊 (包括緩解策略)，請參閱「背景音訊強化」。

連線能力

Android 17 包含下列異動項目，可提升裝置連線能力。

藍牙配對遺失時自動重新配對

Android 17 introduces autonomous re-pairing, a system-level enhancement designed to automatically resolve Bluetooth bond loss.

Previously, if a bond was lost, users had to manually navigate to Settings to unpair and then re-pair the peripheral. This feature builds upon the security improvement of Android 16 by allowing the system to re-establish bonds in the background without requiring users to manually navigate to Settings to unpair and re-pair peripherals.

While most apps will not require code changes, developers should be aware of the following behavior changes in Bluetooth stack:

  • New pairing context: The ACTION_PAIRING_REQUEST now includes the EXTRA_PAIRING_CONTEXT extra which allows apps to distinguish between a standard pairing request and an autonomous system-initiated re-pairing attempt.
  • Conditional key updates: Existing security keys will only be replaced if the re-pairing is successful and new connection meets or exceeds the security level of the previous bond.
  • Modified intent timing: The ACTION_KEY_MISSING intent is now broadcast only if the autonomous re-pairing attempt fails. This reduces unnecessary error handling in the app if the system successfully recovers the bond in the background.
  • User notification: The system manages re-pairing via new UI notifications and dialogs. Users will be prompted to confirm the re-pairing attempt to ensure they are aware of the reconnection.

Peripheral device manufacturers and companion app developers should verify that hardware and app gracefully handle bond transitions. To test this behavior, simulate a remote bond loss using either of the following methods:

  • Manually remove the bond information from the peripheral device
  • Manually unpair the device in: Settings > Connected devices