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，請務必查看影響所有在 Android 14 上執行的應用程式行為變更清單。

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

Android 14 enforces the BLUETOOTH_CONNECT permission when calling the BluetoothAdapter getProfileConnectionState() method for apps targeting Android 14 (API level 34) or higher.

This method already required the BLUETOOTH_CONNECT permission, but it was not enforced. Make sure your app declares BLUETOOTH_CONNECT in your app's AndroidManifest.xml file as shown in the following snippet and check that a user has granted the permission before calling getProfileConnectionState.

<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

自推出以來，JobScheduler 就會在幾秒內，從 onStartJob 或 onStopJob 傳回應用程式。在 Android 14 以下版本 如果工作的執行時間過長，工作就會停止，且失敗並顯示通知。 如果應用程式指定 Android 14 (API 級別 34) 以上版本，且主執行緒的授權時間超過指定時間，應用程式就會觸發 ANR，並顯示「No response to onStartJob」或「No response to onStopJob」錯誤訊息。

這個 ANR 可能會發生在 2 種情況下： 1. 有工作會阻斷主執行緒，導致回呼 onStartJob 或 onStopJob 無法在預期的時間限制內執行及完成。2. 開發人員在 JobScheduler 回呼 onStartJob 或 onStopJob 中執行封鎖工作，導致回呼無法在預期的時間限制內完成。

如要解決 #1 問題，您需要進一步偵錯，解決主執行緒遭到阻斷的原因 您就可以使用 按下 ApplicationExitInfo#getTraceInputStream() 即可取得空值標記 以及追蹤 ANR 事件的時間點如果您可以手動重現 ANR，可以記錄系統追蹤記錄，並使用 Android Studio 或 Perfetto 檢查追蹤記錄，進一步瞭解發生 ANR 時主執行緒正在執行的作業。請注意，直接使用 JobScheduler API 時，可能會發生這種情況 或使用 androidx 程式庫 WorkManager

如要解決 #2 問題，請考慮遷移至 WorkManager， 支援包裝 onStartJob 或 onStopJob 中的任何處理程序 在非同步執行緒中運作

JobScheduler 也會引進一項規定，宣告 ACCESS_NETWORK_STATE 權限 (若使用 setRequiredNetworkType 或 setRequiredNetwork 限制條件。如果應用程式在安排工作時未宣告 ACCESS_NETWORK_STATE 權限，且指定 Android 14 以上版本，則會導致 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 introduces Selected Photos Access, which allows users to grant apps access to specific images and videos in their library, rather than granting access to all media of a given type.

This change is only enabled if your app targets Android 14 (API level 34) or higher. If you don't use the photo picker yet, we recommend implementing it in your app to provide a consistent experience for selecting images and videos that also enhances user privacy without having to request any storage permissions.

If you maintain your own gallery picker using storage permissions and need to maintain full control over your implementation, adapt your implementation to use the new READ_MEDIA_VISUAL_USER_SELECTED permission. If your app doesn't use the new permission, the system runs your app in a compatibility mode.

使用者體驗

安全的全螢幕意圖通知

在 Android 11 (API 級別 30) 版本中，任何應用程式可在手機鎖定時使用 Notification.Builder.setFullScreenIntent 傳送全螢幕意圖。您可以在 AndroidManifest 中宣告 USE_FULL_SCREEN_INTENT 權限，以便在安裝應用程式時自動授予這項權限。

全螢幕意圖通知是專為需要使用者立即處理的高度優先通知設計，例如：來電或使用者設定的鬧鐘。針對指定 Android 14 (API 級別 34) 以上版本為目標版本的應用程式，只有提供通話和鬧鐘功能的應用程式，才可以使用這項權限。凡不符合此設定檔的任何應用程式，Google Play 商店將撤銷預設的 USE_FULL_SCREEN_INTENT 權限。這些政策異動的期限為 2024 年 5 月 31 日。

在使用者更新至 Android 14 之前，這項權限在手機應用程式中仍會保持啟用狀態。使用者可選擇啟用或停用權限。

您可以使用新的 API NotificationManager.canUseFullScreenIntent 檢查應用程式是否具備此權限；如果沒有，您的應用程式可以使用新的意圖 ACTION_MANAGE_APP_USE_FULL_SCREEN_INTENT 啟動設定頁面，以供使用者授予權限。

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：

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

// 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：

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

// 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

Apps and services that target Android 14 (API level 34) or higher and use context-registered receivers are required to specify a flag to indicate whether or not the receiver should be exported to all other apps on the device: either RECEIVER_EXPORTED or RECEIVER_NOT_EXPORTED, respectively. This requirement helps protect apps from security vulnerabilities by leveraging the features for these receivers introduced in Android 13.

Exception for receivers that receive only system broadcasts

If your app is registering a receiver only for system broadcasts through Context#registerReceiver methods, such as Context#registerReceiver(), then it shouldn't specify a flag when registering the receiver.

更安全的動態程式碼載入

If your app targets Android 14 (API level 34) or higher and uses Dynamic Code Loading (DCL), all dynamically-loaded files must be marked as read-only. Otherwise, the system throws an exception. 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.

If you must dynamically load code, use the following approach to set the dynamically-loaded file (such as a DEX, JAR, or APK file) as read-only as soon as the file is opened and before any content is written:

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)

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);

Handle dynamically-loaded files that already exist

To prevent exceptions from being thrown for existing dynamically-loaded files, we recommend deleting and recreating the files before you try to dynamically load them again in your app. As you recreate the files, follow the preceding guidance for marking the files read-only at write time. Alternatively, you can re-label the existing files as read-only, but in this case, we strongly recommend that you verify the integrity of the files first (for example, by checking the file's signature against a trusted value), to help protect your app from malicious actions.

從背景啟動活動的額外限制

For apps targeting Android 14 (API level 34) or higher, the system further restricts when apps are allowed to start activities from the background:

• When an app sends a PendingIntent using PendingIntent#send() or similar methods, the app must opt in if it wants to grant its own background activity launch privileges to start the pending intent. To opt in, the app should pass an ActivityOptions bundle with setPendingIntentBackgroundActivityStartMode(MODE_BACKGROUND_ACTIVITY_START_ALLOWED).
• When a visible app binds a service of another app that's in the background using the bindService() method, the visible app must now opt in if it wants to grant its own background activity launch privileges to the bound service. To opt in, the app should include the BIND_ALLOW_ACTIVITY_STARTS flag when calling the bindService() method.

These changes expand the existing set of restrictions to protect users by preventing malicious apps from abusing APIs to start disruptive activities from the background.

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().

每次 MediaProjection 擷取工作階段都必須取得使用者同意

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 caches the Intent that is returned from MediaProjectionManager#createScreenCaptureIntent, and passes it multiple times to MediaProjectionManager#getMediaProjection.
• Your app invokes MediaProjection#createVirtualDisplay multiple times on the same MediaProjection instance.

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 includes updated lists of restricted non-SDK interfaces based on collaboration with Android developers and the latest internal testing. Whenever possible, we make sure that public alternatives are available before we restrict non-SDK interfaces.

If your app does not target Android 14, some of these changes might not immediately affect you. However, while you can currently use some non-SDK interfaces (depending on your app's target API level), using any non-SDK method or field always carries a high risk of breaking your app.

If you are unsure if your app uses non-SDK interfaces, you can test your app to find out. If your app relies on non-SDK interfaces, you should begin planning a migration to SDK alternatives. Nevertheless, we understand that some apps have valid use cases for using non-SDK interfaces. If you cannot find an alternative to using a non-SDK interface for a feature in your app, you should request a new public API.

To learn more about the changes in this release of Android, see Updates to non-SDK interface restrictions in Android 14. To learn more about non-SDK interfaces generally, see Restrictions on non-SDK interfaces.