行為變更：指定 Android 14 以上版本的應用程式

和先前版本一樣，Android 14 也包含可能會影響應用程式的行為變更。以下行為變更僅適用於指定 Android 14 (API 級別 34) 以上版本的應用程式。如果您的應用程式指定 Android 14 以上版本，建議您視情況修改應用程式，以支援這些行為。

此外，無論應用程式的 targetSdkVersion 為何，請務必查看對所有 Android 14 應用程式有影響的行為變更清單。

核心功能

必須提供前景服務類型

如果您的應用程式以 Android 14 (API 級別 34) 以上版本為目標，則必須為應用程式中的每個前景服務指定至少一個前景服務類型。您應選擇代表應用程式用途的前景服務類型。系統會預期具有特定類型的前景服務，以滿足特定用途。

如果應用程式的用途與上述任一類型無關，強烈建議您遷移邏輯，以便使用 WorkManager 或使用者啟動的資料移轉作業。

在 BluetoothAdapter 中強制執行 BLUETOOTH_CONNECT 權限

針對指定 Android 14 (API 級別 34) 以上版本的應用程式呼叫 BluetoothAdapter getProfileConnectionState() 方法，Android 14 會強制執行 BLUETOOTH_CONNECT 權限。

這個方法已要求 BLUETOOTH_CONNECT 權限，但未強制執行。請務必在應用程式的 AndroidManifest.xml 檔案中宣告 BLUETOOTH_CONNECT，如以下程式碼片段所示，並在呼叫 getProfileConnectionState 之前檢查使用者是否已授予權限。

<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />

OpenJDK 17 更新

Android 14 continues the work of refreshing Android's core libraries to align with the features in the latest OpenJDK LTS releases, including both library updates and Java 17 language support for app and platform developers.

A few of these changes can affect app compatibility:

  • Changes to regular expressions: Invalid group references are now disallowed to more closely follow the semantics of OpenJDK. You might see new cases where an IllegalArgumentException is thrown by the java.util.regex.Matcher class, so make sure to test your app for areas that use regular expressions. To enable or disable this change while testing, toggle the DISALLOW_INVALID_GROUP_REFERENCE flag using the compatibility framework tools.
  • UUID handling: The java.util.UUID.fromString() method now does more strict checks when validating the input argument, so you might see an IllegalArgumentException during deserialization. To enable or disable this change while testing, toggle the ENABLE_STRICT_VALIDATION flag using the compatibility framework tools.
  • ProGuard issues: In some cases, the addition of the java.lang.ClassValue class causes an issue if you try to shrink, obfuscate, and optimize your app using ProGuard. The problem originates with a Kotlin library that changes runtime behaviour based on whether Class.forName("java.lang.ClassValue") returns a class or not. If your app was developed against an older version of the runtime without the java.lang.ClassValue class available, then these optimizations might remove the computeValue method from classes derived from java.lang.ClassValue.

JobScheduler 會強化回呼和網路行為

Since its introduction, JobScheduler expects your app to return from onStartJob or onStopJob within a few seconds. Prior to Android 14, if a job runs too long, the job is stopped and fails silently. If your app targets Android 14 (API level 34) or higher and exceeds the granted time on the main thread, the app triggers an ANR with the error message "No response to onStartJob" or "No response to onStopJob".

This ANR may be a result of 2 scenarios: 1. There is work blocking the main thread, preventing the callbacks onStartJob or onStopJob from executing and completing within the expected time limit. 2. The developer is running blocking work within the JobScheduler callback onStartJob or onStopJob, preventing the callback from completing within the expected time limit.

To address #1, you will need to further debug what is blocking the main thread when the ANR occurs, you can do this using ApplicationExitInfo#getTraceInputStream() to get the tombstone trace when the ANR occurs. If you're able to manually reproduce the ANR, you can record a system trace and inspect the trace using either Android Studio or Perfetto to better understand what is running on the main thread when the ANR occurs. Note that this can happen when using JobScheduler API directly or using the androidx library WorkManager.

To address #2, consider migrating to WorkManager, which provides support for wrapping any processing in onStartJob or onStopJob in an asynchronous thread.

JobScheduler also introduces a requirement to declare the ACCESS_NETWORK_STATE permission if using setRequiredNetworkType or setRequiredNetwork constraint. If your app does not declare the ACCESS_NETWORK_STATE permission when scheduling the job and is targeting Android 14 or higher, it will result in a SecurityException.

啟動圖塊 API

For apps targeting 14 and higher, TileService#startActivityAndCollapse(Intent) is deprecated and now throws an exception when called. If your app launches activities from tiles, use TileService#startActivityAndCollapse(PendingIntent) instead.

隱私權

相片和影片的部分存取權

Android 14 推出「Selected Photos Access」功能，讓使用者可授予應用程式存取媒體庫中特定圖片和影片的權限，而非授予特定類型的所有媒體存取權。

只有在應用程式指定 Android 14 (API 級別 34) 以上版本為目標版本時，才能啟用這項異動。如果您尚未使用相片挑選工具，建議您在應用程式中導入這項工具，以便提供一致的圖片和影片選取體驗，同時提升使用者隱私權，且無須要求任何儲存空間權限。

如果您使用儲存空間權限維護自己的相片庫挑選器，且需要完全掌控實作方式，請調整實作方式，以便使用新的 READ_MEDIA_VISUAL_USER_SELECTED 權限。如果應用程式未使用新權限，系統會以相容模式執行應用程式。

使用者體驗

安全的全螢幕意圖通知

With Android 11 (API level 30), it was possible for any app to use Notification.Builder.setFullScreenIntent to send full-screen intents while the phone is locked. You could auto-grant this on app install by declaring USE_FULL_SCREEN_INTENT permission in the AndroidManifest.

Full-screen intent notifications are designed for extremely high-priority notifications demanding the user's immediate attention, such as an incoming phone call or alarm clock settings configured by the user. For apps targeting Android 14 (API level 34) or higher, apps that are allowed to use this permission are limited to those that provide calling and alarms only. The Google Play Store revokes default USE_FULL_SCREEN_INTENT permissions for any apps that don't fit this profile. The deadline for these policy changes is May 31, 2024.

This permission remains enabled for apps installed on the phone before the user updates to Android 14. Users can turn this permission on and off.

You can use the new API NotificationManager.canUseFullScreenIntent to check if your app has the permission; if not, your app can use the new intent ACTION_MANAGE_APP_USE_FULL_SCREEN_INTENT to launch the settings page where users can grant the permission.

安全性

隱含和待處理意圖的限制

針對以 Android 14 (API 級別 34) 以上版本為目標的應用程式，Android 會透過以下方式，限制應用程式傳送隱含意圖至內部應用程式元件：

  • 隱含意圖只會傳送至匯出的元件。應用程式必須使用明確意圖傳送至未匯出的元件，或將元件標示為已匯出。
  • 如果應用程式建立可變動的待處理意圖，且意圖未指定元件或套件，系統會擲回例外狀況。

這些異動可防止惡意應用程式攔截由應用程式內部元件使用的隱含意圖。

例如，以下是可在應用程式資訊清單檔案中宣告的意圖篩選器：

<activity
    android:name=".AppActivity"
    android:exported="false">
    <intent-filter>
        <action android:name="com.example.action.APP_ACTION" />
        <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>
</activity>

如果您的應用程式嘗試以隱含意圖啟動這個活動，系統會擲回 ActivityNotFoundException 例外狀況：

Kotlin

// Throws an ActivityNotFoundException exception when targeting Android 14.
context.startActivity(Intent("com.example.action.APP_ACTION"))

Java

// Throws an ActivityNotFoundException exception when targeting Android 14.
context.startActivity(new Intent("com.example.action.APP_ACTION"));

若要啟動非匯出活動，應用程式應改用明確意圖：

Kotlin

// This makes the intent explicit.
val explicitIntent =
        Intent("com.example.action.APP_ACTION")
explicitIntent.apply {
    package = context.packageName
}
context.startActivity(explicitIntent)

Java

// This makes the intent explicit.
Intent explicitIntent =
        new Intent("com.example.action.APP_ACTION")
explicitIntent.setPackage(context.getPackageName());
context.startActivity(explicitIntent);

已註冊執行階段的廣播接收器必須指定匯出行為

應用程式和服務若以 Android 14 (API 級別 34) 以上版本為目標版本，並使用已註冊使用情境的接收器，必須利用 RECEIVER_EXPORTED 或 RECEIVER_NOT_EXPORTED 標記，指定應否將接收器匯出至裝置上其他所有應用程式。透過 Android 13 針對這些接收器引進的功能，上述要求有助於避免應用程式出現安全漏洞。

僅接收系統廣播訊息的接收器除外

如果應用程式僅透過 Context#registerReceiver 方法 (例如 Context#registerReceiver())，為系統廣播訊息註冊接收器，則註冊接收器時不應指定標記。

更安全的動態程式碼載入

如果您的應用程式指定 Android 14 (API 級別 34) 以上版本，且使用動態程式碼 載入 (DCL) 後，所有動態載入的檔案都必須標示為唯讀。 否則，系統會擲回例外狀況。我們建議應用程式避免 動態載入程式碼 因為這麼做將會大幅提升應用程式的效能 將遭駭。

如果您必須動態載入程式碼，請使用以下方法來設定 動態載入的檔案 (例如 DEX、JAR 或 APK 檔案) 盡快處於唯讀狀態 會在檔案開啟和寫入任何內容前執行：

Kotlin

val jar = File("DYNAMICALLY_LOADED_FILE.jar")
val os = FileOutputStream(jar)
os.use {
    // Set the file to read-only first to prevent race conditions
    jar.setReadOnly()
    // Then write the actual file content
}
val cl = PathClassLoader(jar, parentClassLoader)

Java

File jar = new File("DYNAMICALLY_LOADED_FILE.jar");
try (FileOutputStream os = new FileOutputStream(jar)) {
    // Set the file to read-only first to prevent race conditions
    jar.setReadOnly();
    // Then write the actual file content
} catch (IOException e) { ... }
PathClassLoader cl = new PathClassLoader(jar, parentClassLoader);

處理已存在的動態載入檔案

為避免現有的動態載入檔案擲回例外狀況，建議您先刪除並重新建立檔案，然後再嘗試在應用程式中動態載入這些檔案。重新建立檔案時，請按照上述指示，在寫入時將檔案標記為唯讀。此外，也可以 將現有檔案重新標示為唯讀 建議您先驗證檔案的完整性 (例如，使用 檢查檔案簽名是否符合信任的值)，協助您保護應用程式 不受惡意動作的影響

從背景啟動活動的額外限制

对于以 Android 14（API 级别 34）或更高版本为目标平台的应用，系统会进一步限制允许应用在后台启动 activity 的时间：

这些更改扩大了一组现有限制条件的范围，目的是防止恶意应用滥用 API 以在后台启动干扰性活动，从而保护用户。

Zip Path Traversal

For apps targeting Android 14 (API level 34) or higher, Android prevents the Zip Path Traversal Vulnerability in the following way: ZipFile(String) and ZipInputStream.getNextEntry() throws a ZipException if zip file entry names contain ".." or start with "/".

Apps can opt-out from this validation by calling dalvik.system.ZipPathValidator.clearCallback().

For apps targeting Android 14 (API level 34) or higher, a SecurityException is thrown by MediaProjection#createVirtualDisplay in either of the following scenarios:

Your app must ask the user to give consent before each capture session. A single capture session is a single invocation on MediaProjection#createVirtualDisplay, and each MediaProjection instance must be used only once.

Handle configuration changes

If your app needs to invoke MediaProjection#createVirtualDisplay to handle configuration changes (such as the screen orientation or screen size changing), you can follow these steps to update the VirtualDisplay for the existing MediaProjection instance:

  1. Invoke VirtualDisplay#resize with the new width and height.
  2. Provide a new Surface with the new width and height to VirtualDisplay#setSurface.

Register a callback

Your app should register a callback to handle cases where the user doesn't grant consent to continue a capture session. To do this, implement Callback#onStop and have your app release any related resources (such as the VirtualDisplay and Surface).

If your app doesn't register this callback, MediaProjection#createVirtualDisplay throws an IllegalStateException when your app invokes it.

更新非 SDK 限制

Android 14 包含更新后的受限非 SDK 接口列表（基于与 Android 开发者之间的协作以及最新的内部测试）。在限制使用非 SDK 接口之前，我们会尽可能确保有可用的公开替代方案。

如果您的应用并非以 Android 14 为目标平台，其中一些变更可能不会立即对您产生影响。然而，虽然您目前仍可以使用一些非 SDK 接口（具体取决于应用的目标 API 级别），但只要您使用任何非 SDK 方法或字段，终归存在导致应用出问题的显著风险。

如果您不确定自己的应用是否使用了非 SDK 接口，则可以测试您的应用来进行确认。如果您的应用依赖于非 SDK 接口，您应该开始计划迁移到 SDK 替代方案。然而，我们知道某些应用具有使用非 SDK 接口的有效用例。如果您无法为应用中的某项功能找到使用非 SDK 接口的替代方案，应请求新的公共 API。

如要進一步瞭解此 Android 版本中的變更，請參閱「Android 14 的非 SDK 介面限制更新內容」。如要進一步瞭解非 SDK 介面的一般資訊，請參閱「非 SDK 介面的限制」。