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。

附註： Android 14 針對健康狀態和遠端訊息用途導入前景服務類型。系統也會針對短期服務、特殊用途和系統豁免保留新的類型。

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) 以上版本為目標版本的應用程式，Android 14 會在呼叫 BluetoothAdapter getProfileConnectionState() 方法時強制執行 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

針對指定 14 以上版本為目標的應用程式，TileService#startActivityAndCollapse(Intent) 已遭淘汰，現在呼叫時會擲回例外狀況。如果您的應用程式從資訊方塊啟動活動，請使用 TileService#startActivityAndCollapse(PendingIntent)。

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

For apps targeting Android 14 (API level 34) or higher, Android restricts apps from sending implicit intents to internal app components in the following ways:

• Implicit intents are only delivered to exported components. Apps must either use an explicit intent to deliver to unexported components, or mark the component as exported.
• If an app creates a mutable pending intent with an intent that doesn't specify a component or package, the system throws an exception.

These changes prevent malicious apps from intercepting implicit intents that are intended for use by an app's internal components.

For example, here is an intent filter that could be declared in your app's manifest file:

<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>

If your app tried to launch this activity using an implicit intent, an ActivityNotFoundException exception would be thrown:

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"));

To launch the non-exported activity, your app should use an explicit intent instead:

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

以 Android 14（API 级别 34）或更高版本为目标平台并使用上下文注册的接收器的应用和服务必须指定以下标志，以指明接收器是否应导出到设备上的所有其他应用：RECEIVER_EXPORTED 或 RECEIVER_NOT_EXPORTED。此要求有助于利用 Android 13 中引入的这些接收器的功能，来保护应用免受安全漏洞的影响。

仅接收系统广播的接收器的例外情况

如果您的应用仅通过 Context#registerReceiver 方法（例如 Context#registerReceiver()）针对系统广播注册接收器，那么它在注册接收器时不应指定标志。

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:

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);

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

針對指定 Android 14 (API 級別 34) 以上版本的應用程式，Android 會透過下列方式避免 Zip Path Traversal 安全漏洞：如果 ZIP 檔案的項目名稱包含「..」或以「/」開頭，則 ZipFile(String) 和 ZipInputStream.getNextEntry() 會擲回 ZipException。

應用程式可透過呼叫 dalvik.system.ZipPathValidator.clearCallback()，選擇不採用此驗證。

每次 MediaProjection 擷取工作階段都必須取得使用者同意

如果應用程式指定的是 Android 14 (API 級別 34) 以上版本，則 MediaProjection#createVirtualDisplay 會在下列任一情況下擲回 SecurityException：

• 應用程式會快取從 MediaProjectionManager#createScreenCaptureIntent 傳回的 Intent，並多次將其傳遞至 MediaProjectionManager#getMediaProjection。
• 應用程式會在同一個 MediaProjection 例項上多次叫用 MediaProjection#createVirtualDisplay。

應用程式必須在每次擷取工作階段前，要求使用者同意。單一擷取工作階段是對 MediaProjection#createVirtualDisplay 的單一叫用，且每個 MediaProjection 例項只能使用一次。

處理設定變更

如果應用程式需要叫用 MediaProjection#createVirtualDisplay 來處理設定變更 (例如螢幕方向或螢幕大小變更)，您可以按照下列步驟更新現有 MediaProjection 例項的 VirtualDisplay：

1. 使用新的寬度和高度呼叫 VirtualDisplay#resize。
2. 提供新的 Surface，並將新的寬度和高度傳遞給 VirtualDisplay#setSurface。

註冊回呼

應用程式應註冊回呼，以便處理使用者未同意繼續擷取影像的情況。如要這麼做，請實作 Callback#onStop，並讓應用程式釋出任何相關資源 (例如 VirtualDisplay 和 Surface)。

如果應用程式未註冊此回呼，MediaProjection#createVirtualDisplay 在應用程式叫用時會擲回 IllegalStateException。

更新非 SDK 限制

基於與 Android 開發人員合作及最新的內部測試，Android 14 包含更新後的受限制非 SDK 介面清單。在限制非 SDK 介面之前，我們盡可能確保公開替代方案的可得性。

如果您的應用程式並不是以 Android 14 為目標版本，則此處所述的某些變更可能不會立即對您造成影響。雖然您目前可以使用某些非 SDK 介面 (視應用程式的目標 API 級別而定)，但使用任何非 SDK 方法或欄位時，均可能面臨應用程式故障的高度風險。

如果不確定應用程式是否使用非 SDK 介面，可對應用程式進行測試以便確認。如果您的應用程式仰賴非 SDK 介面，則建議您開始規劃遷移至 SDK 替代方案。我們瞭解有些應用程式可使用非 SDK 介面運作。如果您除了為應用程式中的某個功能使用非 SDK 介面外，已別無他法，則應要求新的公用 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」。