行为变更：以 Android 14 或更高版本为目标平台的应用

与之前的版本一样，Android 14 包含一些行为变更，这些变更可能会影响您的应用。以下行为变更仅影响以 Android 14（API 级别 34）或更高版本为目标平台的应用。如果您的应用以 Android 14 或更高版本为目标平台，您应该修改自己的应用以适当地支持这些行为（如果适用）。

请务必查看对 Android 14 上运行的所有应用都有影响的行为变更列表（无论应用的 targetSdkVersion 如何）。

核心功能

前台服务类型是必填项

如果您的应用以 Android 14（API 级别 34）或更高版本为目标平台，则必须为应用中的每项前台服务指定至少一个前台服务类型。您应该选择一个能够代表应用用例的前台服务类型。系统需要特定类型的前台服务满足特定用例。

注意：Android 14 针对运行状况和远程消息传递用例引入了前台服务类型。系统还为简短服务、特殊用例和系统豁免保留新的类型。

如果应用中的用例与这些类型均不相关，强烈建议您迁移逻辑以使用 WorkManager 或用户发起的数据传输作业。

在 BluetoothAdapter 中强制执行 BLUETOOTH_CONNECT 权限

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 将继续更新 Android 的核心库，以与最新 OpenJDK LTS 版本中的功能保持一致，包括适合应用和平台开发者的库更新和 Java 17 语言支持。

以下变更可能会影响应用兼容性：

• 对正则表达式的更改：现在，为了更严格地遵循 OpenJDK 的语义，不允许无效的组引用。您可能会看到 java.util.regex.Matcher 类抛出 IllegalArgumentException 的新情况，因此请务必测试应用中使用正则表达式的情形。如需在测试期间启用或停用此变更，请使用兼容性框架工具切换 DISALLOW_INVALID_GROUP_REFERENCE 标志。
• UUID 处理：现在，验证输入参数时，java.util.UUID.fromString() 方法会执行更严格的检查，因此您可能会在反序列化期间看到 IllegalArgumentException。如需在测试期间启用或停用此变更，请使用兼容性框架工具切换 ENABLE_STRICT_VALIDATION 标志。
• ProGuard 问题：有时，在您尝试使用 ProGuard 缩减、混淆和优化应用时，添加 java.lang.ClassValue 类会导致问题。问题源自 Kotlin 库，该库会根据 Class.forName("java.lang.ClassValue") 是否会返回类更改运行时行为。如果您的应用是根据没有 java.lang.ClassValue 类的旧版运行时开发的，则这些优化可能会将 computeValue 方法从派生自 java.lang.ClassValue 的类中移除。

JobScheduler 强化了回调和网络行为

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.

Tiles 发布 API

对于以 Android 14 及更高版本为目标平台的应用， TileService#startActivityAndCollapse(Intent) 已弃用，现在会抛出 调用时抛出异常。如果您的应用从功能块启动 activity，请使用 TileService#startActivityAndCollapse(PendingIntent)。

隐私设置

拥有对照片和视频的部分访问权限

Android 14 引入了所选照片访问权限，可让用户授权应用访问其媒体库中的特定图片和视频，而不是授予对指定类型的所有媒体的访问权限。

仅当您的应用以 Android 14（API 级别 34）或更高版本为目标平台时，才会启用此变更。如果您还没有使用照片选择器，建议您在应用中实现该选择器，以便在选择图片和视频时提供一致的体验，同时还可以加强用户隐私保护，而无需请求任何存储权限。

如果您使用存储权限维护自己的图库选择器，并且需要完全控制您的实现，请调整您的实现，以使用新的 READ_MEDIA_VISUAL_USER_SELECTED 权限。如果您的应用不使用新权限，系统会在兼容模式下运行应用。

用户体验

安全的全屏 intent 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

对隐式 intent 和待处理 intent 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);

在运行时注册的广播接收器必须指定导出行为

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.

更安全的动态代码加载

如果您的应用以 Android 14（API 级别 34）或更高版本为目标平台，并且使用动态代码加载 (DCL) 功能，则必须将所有动态加载的文件标记为只读。否则，系统会抛出异常。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。

如果必须动态加载代码，请使用以下方法，在动态文件（例如 DEX、JAR 或 APK 文件）打开并写入任何内容之前立即将其设为只读：

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);

处理已存在的动态加载文件

为防止系统对现有动态加载的文件抛出异常，我们建议您先删除并重新创建文件，然后再尝试在应用中重新动态加载这些文件。重新创建文件时，请按照上述指南在写入时将文件标记为只读。或者，您可以将现有文件重新标记为只读，但在这种情况下，我们强烈建议您先验证文件的完整性（例如，对照可信值检查文件的签名）以保护应用免遭恶意操作的影响。

针对从后台启动 activity 的其他限制

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：

• 现在，当应用使用 PendingIntent#send() 或类似方法发送 PendingIntent 时，如果它想要授予自己的后台 activity 启动待处理 intent 的启动特权，则必须选择启用。如需选择启用，应用应通过 setPendingIntentBackgroundActivityStartMode(MODE_BACKGROUND_ACTIVITY_START_ALLOWED) 传递 ActivityOptions 软件包。
• 当可见应用绑定了另一个后台应用的服务时 bindService() 方法，可见应用现在必须 如果它想要将自己的后台活动 绑定服务。要选择启用，应用应包含 BIND_ALLOW_ACTIVITY_STARTS 标志，在调用 bindService() 方法。

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。

压缩路径遍历

对于以 Android 14（API 级别 34）或更高版本为目标平台的应用，Android 会通过以下方式防止 Zip 路径遍历漏洞：如果 zip 文件条目名称包含“..”或以“/”开头，则 ZipInputStream.getNextEntry() 会抛出 ZipException。ZipFile(String)

应用可以通过调用 dalvik.system.ZipPathValidator.clearCallback() 选择停用此验证。

每次 MediaProjection 捕获会话都需要征得用户同意

对于以 Android 14（API 级别 34）或更高版本为目标平台的应用，在以下任一情况下，MediaProjection#createVirtualDisplay 会抛出 SecurityException：

• 您的应用会缓存从 MediaProjectionManager#createScreenCaptureIntent 返回的 Intent，并将其多次传递给 MediaProjectionManager#getMediaProjection。
• 您的应用在同一 MediaProjection 实例上多次调用 MediaProjection#createVirtualDisplay。

您的应用必须在每次捕获会话之前征求用户同意。单次拍摄会话是指对 MediaProjection#createVirtualDisplay 的单次调用，且每个 MediaProjection 实例只能使用一次。

处理配置变更

如果您的应用需要调用 MediaProjection#createVirtualDisplay 来处理配置更改（例如屏幕方向或屏幕尺寸更改），您可以按照以下步骤更新现有 MediaProjection 实例的 VirtualDisplay：

1. 使用新的宽度和高度调用 VirtualDisplay#resize。
2. 为 VirtualDisplay#setSurface 提供具有新宽度和高度的新 Surface。

注册回调

您的应用应注册一个回调，以处理用户不同意继续拍摄会话的情况。为此，请实现 Callback#onStop 并让您的应用发布所有相关资源（例如 VirtualDisplay 和 Surface）。

如果您的应用未注册此回调，MediaProjection#createVirtualDisplay 会在应用调用此回调时抛出 IllegalStateException。

更新后的非 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.

如需详细了解此 Android 版本中的变更，请参阅 Android 14 中有关限制非 SDK 接口的更新。如需全面了解有关非 SDK 接口的详细信息，请参阅对非 SDK 接口的限制。